Options Méditerranéennes Série B n. 56 Water Saving in Mediterranean Agriculture & Future Research Needs WASAMED Project (EU contract ICA3-CT-2002-10013) Proceedings of the International Conference 14-17 February 2007 - Valenzano, (Italy) Vol. II Cover: A. Filippetti - “Il Prodigio dell’Acqua” Opinions, data and facts exposed in this number are under the responsibility of the authors and do not engage either CIHEAM or the Member-countries. Les opinions, les données et les faits exposés dans ce numéro sont sous la responsabilité des auteurs et n'engagent ni le CIHEAM, ni les pays membres. CIHEAM Centre International de Hautes Etudes Agronomiques Méditerranéennes Options méditerranéennes Directeur de la publication: Bertrand Hervieu Water Saving in Mediterranean Agriculture & Future Research Needs WASAMED Project (EU contract ICA3-CT-2002-10013) Proceedings of the International Conference 14-17 February 2007 - Valenzano, (Italy) Edited by: N. Lamaddalena, C. Bogliotti, M. Todorovic, A. Scardigno 2007 This volume of Options Méditerranéennes Series B has been formatted and paged up by the IAM Bari Editing Board La maquette et la mise en page de ce volume de Options Méditerranéennes Series B ont été réalisées à l'Atelier d'Edition de l'IAM Bari Copy number : 250 Printed by Ideaprint - Bari, Italy tel. +39 080 542 45 87 e-mail: [email protected] Water Saving in Mediterranean Agriculture & Future Research Needs WASAMED Project (EU contract ICA3-CT-2002-10013) Proceedings of the International Conference 14-17 February 2007 - Valenzano, (Italy) Edited by: N. Lamaddalena, C. Bogliotti, M. Todorovic, A. Scardigno Bari : CIHEAM (Centre International de Hautes Etudes Agronomiques Méditerranéennes) Vol. I, p. 451; Vol. II, p. 336; Vol. III, p. 351 Options Méditerranéennes, Série B : N. 56 ISSN : 1016-1228 ISBN : 2-85352-354-3 © CIHEAM, 2007 Reproduction partielle ou totale interdite sans l'autorisation d'«Options Méditerranéennes» Reproduction in whole or in part is not permitted without the consent of «Options Méditerranéennes» CONTENTS Page VOLUME I FOREWORD 27 INTRODUCTION 31 SESSION 1: Water Use Efficiency and Water Productivity 35 A QUANTITATIVE FRAMEWORK FOR THE SYSTEMATIC ANALYSIS OF POTENTIAL WATER SAVINGS IN AGRICULTURE T. C. Hsiao, P. Steduto and E. Fereres 37 ASSESSING THE SIMDualKc MODEL FOR IRRIGATION SCHEDULING SIMULATION IN MEDITERRANEAN ENVIRONMENTS J. Rolim, P. Godinho, B. Sequeira, P. Paredes and L.S. Pereira 49 LEMON EVAPOTRANSPIRATION AND YIELD UNDER WATER DEFICIT IN JORDAN VALLEY M. Shatanawi, J. Al-Bakri and A. A. Suleiman 63 WATER REQUIREMENTS OF INDIVIDUAL OLIVE TREES IN RELATION TO CANOPYAND ROOT DEVELOPMENT M. M. Masmoudi, C. Masmoudi-Charfi , I. Mahjoub and N. Ben Mechlia 73 PERFORMANCE OF ‘GOLDEN DELICIOUS’ APPLES GROWN IN A SEMI-ARID REGION UNDER PARTIAL ROOTZONE DRYING J. A. Zegbe, A. Serna and Á. G. Bravo 81 MEASUREMENTS OF SAP FLOW FOR APPLE TREES IN RELATION TO CLIMATIC AND WATERING CONDITIONS Z. Nasr and N. Ben Mechlia 91 7 Page REDUCING AGRICULTRUAL WATER DEMAND IN LIBYA THROUGH THE IMPROVEMENT OF THE WATER USE EFFICIENCY AND THE CROP WATER PRODUCTIVITY S. A. Alghariani 99 WATER PRODUCTIVITY ANALYSIS OF SOME IRRIGATED CROPS IN IRAN A. Montazar, and H. Rosari 109 SPATIAL SIMULATION OF WATER USE EFFICIENCY IN A MEDITERRANEAN ENVIRONMENT, M. Rinaldi and R. Ubaldo 121 IMPROVING WATER USE EFFICIENCY OF FIELD CROPS THROUGH REGULATED DEFICIT IRRIGATION K. Karaa, F. Karam and N.R Tarabey 143 DEFICIT IRRIGATION OF SUNFLOWER UNDER MEDITERRANEAN ENVIRONMENTAL CONDITIONS M. Todorovic, R. Albrizio and Lj. Zivotic 153 RELATIONSHIP OF WATER USE WITH BIOPHYSICAL AND YIELD PARAMETERS UNDER VARIOUS IRRIGATION LEVELS IN RAPESEED CULTIVARS B. Delkhosh 169 EFFICIENCE DE L’UTILISATION DE L’EAU CHEZ LE BLE ET L’ORGE SOUS DIFFERENTS REGIMES HYDRIQUES ET DE FERTILISATION AZOTEE, DANS DES CONDITIONS SUBHUMIDES DE TUNISIE H. J. Mellouli, M. Ben Naceur, M. El Felah, M. S. El Gharbi, M. Kaabia, H. Nahdi, G. A. Slafer and M. Karrou 179 CHART FOR MONITORING WHEAT IRRIGATION IN REAL TIME M. Jabloun and A. Sahli 8 191 Page PARTITIONING ENERGY FLUXES BETWEEN CANOPY AND SOIL SURFACE UNDER SPARSE MAIZE DURING WET AND DRY PERIODS T.A. Zeggaf , H. Anyoji, S. Takeuchi and T. Yano 201 PLANT - SOIL WATER DYNAMICS OF ALTERNATE FURROW AND REGULATED DEFICIT IRRIGATION FOR TWO LEGUME CROPS IN THE FERGANA VALLEY, UZBEKISTAN H. Webber, C. Madramootoo, M. Bourgault, M. Horst, G. Stulina and D. Smith 213 LEGUME PRODUCTION AND IRRIGATION STRATEGIES IN THE ARAL SEA BASIN:YIELD, YIELD COMPONENTS AND WATER RELATIONS OF COMMON BEAN (PHASEOLUS VULGARIS) AND GREEN GRAM (VIGNA RADIATA (L.) WILCZEK) M. Bourgault, C. A. Madramootoo, H. A. Webber, M. G. Horst, G. Stulina and D. L. Smith 223 IRRIGATION WATER SAVING VIA SCHEDULING IRRIGATION OF SNAP BEAN AND DIRECTION OF SOIL WATER MOVEMENT UNDER DRIP IRRIGATION SYSTEM, R.W. El Gendy, A.M. Gadalla, A. Hamdy, M. El Moniem and A. Fahmy 235 IRRIGATION SCHEDULING CALENDARS DEVELOPMENT AND VALIDATION UNDER ACTUAL FARMERS’ CONDITIONS IN ARID REGIONS OF TUNISIA K. Nagaz, M. M. Masmoudi and N. Ben Mechlia 249 EFFECT OF DRIP IRRIGATION REGIMES ON YIELD AND QUALITY OF FIELD GROWN BELL PEPPER S. Metin Sezen, A. Yazar and S. Eker 261 DEFICIT IRRIGATION SCHEDULING IN PROCESSING TOMATO G. Gatta, M.M. Giuliani, M. Monteleone, E. Nardella and A. De Caro 277 9 Page SESSION 2: Irrigation System Performance and Management 291 ASSESSING ADAPTIVE CAPACITY OF LARGE IRRIGATION DISTRICTS TOWARDS CLIMATE CHANGE AND SOCIAL CHANGE WITH IRRIGATION MANAGEMENT PERFORMANCE MODEL T. Nagano, K. Hoshikawa, S. Donma, T. Kume, S. Önder, B. Özekici, R.Kanber and T. Watanabe 293 HIDROGEST, A GIS FRAMEWORK FOR INTEGRATION OF DECISION SUPPORT TOOLS FOR IMPROVED WATER USE AND PARTICIPATORY MANAGEMENT IN PRESSURIZED ON-DEMAND IRRIGATION SYSTEMS P. Mateus, L- Correia and L. S. Pereira 303 DIAGNOSTIC ANALYSIS FOR THE REHABILITATION OF AN IRRIGATION SYSTEM IN THE STOLAC MUNICIPALITY (BOSNIA HERZEGOVINA) E. Bresci and T. Letterio 319 MEASUREMENT AND EVALUATION OF PERFORMANCE OF MANAGEMENT-OPERATION AND MAINTENANCE OF IRRIGATION SCHEMES IN BEFORE-AND-AFTER TURNOVER: A CASE STUDY AT GREAT MENDERES BASIN, TURKEY C. Koç, D. Akar and K. Özdemir 329 DESIGN OF REAL-TIME CONTROL ALGORITHM FOR ON-DEMAND OPERATION OF IRRIGATION CHANNELS G. M. El-Kassar, Kutija and P. E. O’Connell 341 MEASUREMENT AND IMPROVEMENT OF THE ENERGY EFFICIENCY AT PUMPING STATIONS M.A. Moreno-Hidalgo, P.A. Carrión , P. Planells , J.F. Ortega and J.M. Tarjuelo 353 11 Page ENERGY SAVING FOR A PUMPING STATION SERVING AN ONDEMAND IRRIGATION SYSTEM: A STUDY CASE, F. Barutçu, N.Lamaddalena and U. Fratino 367 WATER SAVING SCENARIOS FOR COTTON UNDER SURFACE IRRIGATION: ANALYSIS WITH THE DSS SADREG H. Darouich, J. M. Gonçalves and L. S. Pereira 381 DEPIVOT, A SOFTWARE TOOL FOR IMPROVED WATER USE WITH CENTER-PIVOT SPRINKLER SYSTEMS M. I. Valín and L. S. Pereira 397 ANALYSIS OF THE DRY SPELL FOR OPERATION DAM IN THE NORTH OF TUNISIA Mathlouthi Majid and Lebdi Fethi 407 MANAGEMENT OF SUB-SURFACE DRIP IRRIGATION SYSTEM AND WATER SAVING IN GREENHOUSE A. A. Abou Kheira and Amr H. El-Shafie 419 EFFICIENCY OF FURROW IRRIGATION ON SANDY SOIL AMENDED WITH BENTONITE IN ARID AND SEMI ARID REGION M. Benkhelifa, Y. Daoud, M. Belkhodja and D. Tessier 12 439 Page VOLUME II SESSION 3: Use of Non conventional Water Resources in Irrigated Agriculture 31 USE OF NON CONVENTIONAL WATER RESOURCES IN IRRIGATED AGRICULTURE F. El-Gamal 33 WATER SAVING POTENTIALITIES THROUGH THE USE OF SALINE WATER AND THE APPLICATION OF DEFICIT IRRIGATION A. Hamdy, N. Katerji, M. Mastrorilli and A. Dayyoub 45 IRRIGATION STRATEGIES FOR OPTIMAL USE OF SALINE WATER IN MEDITERRANEAN AGRICULTURE G. Crescimanno and P. Garofano 61 EFFECT OF SUPPLEMENTARY SALINE IRRIGATION ON YIELD AND STOMATAL CONDUCTANCE OF WHEAT UNDER THE MEDITERRANEAN CLIMATIC CONDITIONS A. Yazar, A. Hamdy, B. Gencel , M. S. Sezen and M. Koç 73 USE OF SALINE IRRIGATION WATER FOR PRODUCTION OF SOME LEGUMES AND TUBER PLANTS A. M. Gadalla A. Hamdy and Y. G. M. Galal 85 SEA WATER STRESS AFFECTS MITOCHONDRIAL PROLINE OXIDATION BUT NOT ALTERNATIVE OXIDASE ACTIVITY IN DURUM WHEAT GERMINATING SEEDLINGS M.N. Laus, Z. Flagella, D. Trono, M. Soccio, N. Di Fonzo and D. Pastore 99 SUBMERGED REVERSE OSMOSIS PLANT (SROP) D. N. Bapat 109 13 Page TREATED WASTEWATER SOURCES: ACTIONS TOWARDS SUSTAINABLE AND SAFELY USE IN THE NEAR EAST AND ACHIEVING FOOD SECURITY IN WATER-SCARCE POOR RURAL COMMUNITIES R. Choukr-Allah 115 PLANNING FOR WASTEWATER REUSE F. Fresa, F. Melli, A.F. Piccinni, V. Santandrea and V. Specchio 129 THE ROLE OF SMALL SCALE WASTEWATER TREATMENT IN THE DEVELOPMENT OF WATER RESOURCES IN WEST BANK OF PALESATINE M. Y. Sbeih 149 IRRIGATION OF VEGETABLES AND FLOWERS WITH TREATED WASTEWATER I. Papadopoulos, D. Chimonidou, P. Polycarpou and S. Savvides 163 RESPONSE OF DURUM WHEAT (Triticum durum Desf.) CULTIVAR ACSAD 1107 TO SEWAGE SLUDGE AMENDMENT UNDER SEMI ARID CLIMATE L. Tamrabet, H. Bouzerzour, M. Kribaa and M. Makhlouf 173 REUSE OF MEMBRANE FILTERED MUNICIPAL WASTEWATER FOR IRRIGATING VEGETABLE CROPS A. Lopez, A. Pollice, G. Laera, A. Lonigro, P. Rubino and R. Passino 181 USE OF SANDS OF THE DUNES LIKE BIOFILTER IN THE PURIFICATION OF WASTE WATER OF THE TOWN OF OUARGLA (ALGERIA) F. Ammour and M. Messahel 191 SALMONELLA TRANSPORT AND PERSISTENCE IN SOIL AND PLANT IRRIGATED WITH ARTIFICIALLY INOCULATED RECLAIMED WATER: CLIMATIC EFFECTS MP. Palacios, P. Lupiola, F. Fernandez-Vera V. Mendoza and MT.Tejedor 14 199 Page SESSION 4: Innovative Approaches and Tools for Water Saving 207 A GIS-BASED WATER RESOURCES INFORMATION SYSTEM: A REGIONAL DSS FOR IWRM K. Abu-Zeid and O. Elbadawy 209 USE OF THE GENETIC ALGORITHM FOR THE OPTIMAL OPERATION OF MULTI-RESERVOIRS ON DEMAND IRRIGATION SYSTEM O. Gharsallah, I. Nouiri, F. Lebdi and N. Lamaddalena 217 AVAILABILITY AND ACCURACY OF MEDITERRANEAN DATABASES RELEVANT TO AGRICULTURAL WATER USES J. Crimi, M. Khawlie, M. Awad, A. Sgobbi and C. Giupponi 229 THE NOSTRUM-DSS GUIDELINES FOR IMPROVED DEVELOPMENT AND ADOPTION OF DECISION SUPPORT SYSTEMS IN INTEGRATED WATER RESOURCES MANAGEMENT IN THE MEDITERRANEAN BASIN C. Giupponi, Y. Depietri, R. Camera, J. Crimi and A. Sgobbi 239 APPLICATION OF THE NETSYMOD APPROACH IN SUPPORT OF DECISIONS ABOUT IRRIGATION MANAGEMENT A. Fassio, C. Giupponi, A. Sgobbi and J. Mysiak 249 MODELS AND DECISION SUPPORT SYSTEMS FOR PARTICIPATORY DECISION MAKING IN INTEGRATED WATER RESOURCE MANAGEMENT A. Sgobbi and C. Giupponi 259 AGENT-BASED MODELLING AND SIMULATION IN THE IRRIGATION MANAGEMENT SECTOR: APPLICATIONS AND POTENTIAL Fani A.Tzima, Ioannis N. Athanasiadis and Pericles A. Mitkas 273 15 Page PILOTAGE DE L’IRRIGATION PAR LA METHODE DURAYONNEMENT GLOBAL H. Bellouch, A. Baroud, M. Taoura et B. Sirat 287 APPORT DES TECHNIQUES GEO-SPATIALES POUR LA CARACTÉRISATION DE LA QUALITE DES EAUX SOUS-TERRAINES DES OASIS DE LA VALLÉE DU DRAA - CAS DE LA NAPPE DE FEZOUATA H.D. Cherkaoui, R. Moussadek et H. Sahbi 293 A FRAMEWORK FOR IRRIGATION MANAGEMENT DURING DROUGHT: APPLICATION IN TWO CASE STUDIES IN THE TAGUS BASIN, SPAIN M. Moneo and A. Iglesias 305 WATER MANAGEMENT UNDER EXTREME WATER SCARCITY: SCENARIO ANALYSES FOR THE JORDAN RIVER BASIN, USING WEAP21 H. Hoff, C. Swartz, D. Yates and K. Tielborger 321 ROSE CULTIVATION IN CYPRUS UNDER TWO IRRIGATION REGIMES USING LOCAL SUBSTRATES D. Chimonidou, L. Vassiliou, P. Kerkides and M. Psyhoyiou 16 333 Page VOLUME III SESSION 5: Integrated Water Management: Institutional, Policy, Social, Economic and Environmental aspects 31 PROBLEMS AND SOLUTIONS FOR WATER USER ASSOCIATIONS IN THE GEDİZ BASIN S. Kiymaz, B. Ozekici and A. Hamdy 33 INTEGRATING STRATEGIES FOR AN EFFICIENT WATER MANAGEMENT UNDER UNCERTAINITY: EMPIRICAL EVIDENCE IN SPAIN I. Blanco Gutiérrez and C. Varela Ortega 45 IRRIGATION PRICING POLICY AIMED AT THE ENHANCEMENT OF WATER SAVING INNOVATION AT FARM LEVEL. A CASE STUDY G. Gatta, G. Giannoccaro, M. Monteleone, M. Prosperi and G. Zanni 65 DEVELOPMENT OF AN INCOME GENERATING AGRICULTURAL MANAGEMENT VIA IRRIGATION SYSTEM IMPROVEMENT IN LOWER SEYHAN PLAIN S. Donma and Z. Coşkun 83 OPTIMAL WATER PRODUCTIVITY OF IRRIGATION SYSTEMS IN A SEMI-ARID REGION A. Montazar, M.H. Nazari Far and E. Mardi 87 ASSESSMENT OF THE SOCIO-ECONOMIC AND AGRICULTURAL ASPECTS IN WATER RESOURCES USING GIS, A CASE STUDY FROM EGYPT K. Maherzi, A. Afify, M. A. Motaleb and A. Hamdy 99 EFFICIENCY GAINS FROM POTENTIAL WATER MARKET IN IRAN: SAVEH REGION CASE STUDY G. H. Kiani 113 17 Page WATER USE LICENSING VERSUS ELECTRICITY POLICY REFORM TO STOP SEAWATER INTRUSION S. Zekri 121 EVALUATION OF DIFFERENT TRADITIONAL WATER MANAGEMENT SYSTEMS IN SEMI-ARID REGIONS (CASE STUDY FROM IRAN) M.R. Ghanbarpour, E. Ahmadi and S. Gholami 133 CONTOUR RIDGE EFFICIENCY ON LAND EROSION, WATER-FILLING AND SILTING UP OF A HILL RESERVOIR IN A SEMI-ARID REGION IN TUNISIA N. Baccari, S. Nasri, Boussema M. Rached and J. M. Lamachère 141 SOIL PHYSICAL DEGRADATION OF RANGELANDS UNDER CONTINUOUS GRAZING AT THE ZACATECAS, MEXICO HIGHLANDS F. G. Echavarría, A. Serna, R. Bañuelos, M. J. Flores, R. Gutiérrez and H. Salinas 151 A METHODOLOGY TO RELATE GROUNDWATER SALINITY TO IRRIGATION DELIVERY SCHEDULES: A CASE STUDY IN SOUTHERN ITALY I. Oueslati, D. Zaccaria, M. Vurro and N. Lamaddalema 163 ASSESSMENT OF VULNERABLE ZONES TO NITRATE POLLUTION: A STUDY CASE IN THE APULIA REGION I.Oueslati, M. Vurro, V. Uricchio and N. Lamaddalena 181 ASSESSMENT OF ON-FARM WATER MANAGEMENT FOR SUSTAINABLE AGRICULTURAL DEVELOPMENT IN NILE DELTA W. H. El Hassan., F. El Gamal and Y. Kitamura 197 WATER RESOURCES IN SYRIA AND THEIR DEVELOMENT PROCEDURES A. Kaisi, Y. Mohammad and Y. Mahrouseh 18 209 Page AGRICULTURAL WATER SAVING IN GREECE A. Karamanos, N. Dercas, P. Londra and S. Aggelides 225 WATER RESOURCES OF ALGERIA AVAILABILITY AND NEEDS M. Messahel and MS. Benhafid 235 SUSTAINABILITY DIMENSIONS OF THE PRACTICAL EXPERIENCE IN WATER SAVING FOR AGRICULTURE IN PALESTINIAN AUTHORITY TERRITORIES B. Dudeen 243 AN ANALYSIS OF LOSSES AND GAINS IN INDUS RIVER SYSTEM OF PAKISTAN F. H. Kharal and S. Ali 253 19 Page SESSION 6 : Euro-Mediterranean cooperation 263 IDENTIFYING RESEARCH AND DEVELOPMENT TARGETS FOR THE MANAGEMENT OF LIMITED WATER RESOURCES IN THE MEDITERRANEAN: BACKGROUND AND BRIEF OUTLINE OF THE WASAMED CASE C. Bogliotti and M. Todorovic 265 IRRIQUAL: SUSTAINABLE ORCHARD IRRIGATION FOR IMPROVING FRUIT QUALITY AND SAFETY J.J. Alarcón and M. Pérez de Madrid 285 WATNITMED - MANAGEMENT IMPROVEMENTS OF WUE AND NUE OF MEDITERRANEAN STRATEGIC CROPS (WHEAT AND BARLEY) G. A. Slafer, M. Karrou, F. Karam, C. Thabet, H. J. Spiertz, R. Dahan, J. Foulkes, S. Nogues, P. Peltonen-Sainio, R. Albrizio, J. Y. Ayad and H. J. Mellouli 291 FARM LEVEL OPTIMAL WATER MANAGEMENT: ASSISTANT FOR IRRIGATION UNDER DEFICIT (FLOW-AID) J. Balendonck, C. Stanghellini and J. Hemming 301 AQUASTRESS: MITIGATION OF WATER STRESS THROUGH NEW APPROACHES TO INTEGRATING MANAGEMENT, TECHNICAL, ECONOMIC AND INSTITUTIONAL INSTRUMENTS - DEFINITION OF THE CASE STUDIES R. Passino, A. Battaglia, D. Assimacopoulos, S. Apostolaki and P. Katsiardi 313 PROMOTING GENDER MAINSTREAMING IN INTEGRATED WATER RESOURCES MANAGEMENT THROUGH INFORMATION COLLECTION AND DISSEMINATION. THE GEWAMED PROJECT, J. A. Sagardoy Alonso 325 21 Page ASSESSMENT OF THE ENVIRONMENTAL SUSTAINABILITY OF IRRIGATED AGRICULTURE IN A LARGE-SCALE SCHEME – A CASE STUDY D. Zaccaria, M. Inversi and N. Lamaddalena 337 DEFICIT IRRIGATION AS A MEANS OF REDUCING AGRICULTURAL WATER USE E. Fereres, M. Morales and M.A. Soriano 22 347 FOREWORD In the Southern Mediterranean, as well as in many other arid and semi-arid contexts, agriculture is one of the major economic driving forces contributing to more than 50% of the gross income of the region. Agriculture represents the main activity for a large part of the rural population and constitutes the tissue of social relationships. Nevertheless, due to unfavourable climatic conditions, agriculture is widely relied on irrigation and water withdrawal for agricultural use accounts for more than 80% of total freshwater abstraction. Most of the renewable water resources in water scarce regions, and particularly in the Mediterranean, are already fully exploited (or even overexploited in certain areas) and funds to build important infrastructures are shrinking. Past experience and initiatives have often proved the non-sustainability of agricultural water management based only on infrastructure-supply strategy. Hence, water demand management has been affirmed as the most appropriate long-term vision strategy to cope with the dynamics of supplydemand imbalance. Certainly, agriculture is the main sector in which water saving opportunities can be pursued and achieved since the agricultural water losses are estimated at more than 50% of sectorial water withdrawal. The contribution of agriculture to a more sustainable development is increasingly pursued at European level (through the integration of sustainability principles of Lisbon Process in both the EU Water Framework Directive and the Common Agricultural Policy) as a strategy that could be wisely developed across the Euro-Mediterranean region. In view of that, the European Commission has been very active in the promotion of relevant research initiatives in the water sector in third countries through the International Cooperation dimension of the RTD Framework Programme as well the launch of the EU Water Initiative specifically addressed to meet the Millennium Development Goals. Since the beginning of Nineties, the Mediterranean Agronomic Institute of Bari (IAMB), part of the International Centre for Advanced Mediterranean Agronomic Studies (CIHEAM), has been strengthened the networking activities of the relevant Mediterranean partners on i) Use of Non-conventional Water Resources in irrigation, ii) Eco-physiology and modelling for Water Use Efficiency, iii) Assessment and Improvement of Performances of Collective Irrigation Systems. In 1998, a fruitful collaboration between CIHEAM and the European Commission (DG-RELEX) has been intensified within the frame of the Regional Action Plan on “Regional co-operation in agricultural sector on training, promotion of research and communication of scientific and technical information in the context of economic transition”. This action has enabled funding to improve and expand the networking activities more towards onground implementation of research findings in many pilot areas in the Southern Mediterranean countries. Contemporarily, the Mediterranean Agronomic Institute of 23 Bari had carried out a 4-years long cooperation with the World Bank on the implementation of Participatory Irrigation Management in arid and semi-arid regions of Mediterranean and surrounding regions. Thematic Network on “WAter SAving in MEDiterranean agriculture” (WASAMED) represents a logical continuation of the previous initiatives and it is granted in 2003 by the International Scientific Cooperation of the Directorate General of Research, European Commission, within the frame of the 5th Framework Programme. WASAMED project (ICA3-CT2002-10013; http://wasamed.iamb.it) is coordinated by CIHEAM-Bari Institute and involves 42 partners from 16 countries including scientific institutions, decision and policy makers, researchers, end-users, Water User Associations (WUAs) and NGOs. The project lasts for four years seeking consensus on best options, goals and indicators for water saving in the region mainly through the exchange of knowledge, dissemination of information and realization of five Euro-Mediterranean Workshops and an International Conference at the end of the programme. This number of “Option Méditerranéennes” consists of three volumes and represents the proceedings of the final WASAMED event, International Conference on “Water Saving in Mediterranean Agriculture and Future Research Needs” carried out at IAMBari, in the period 14-17 February 2007. The Proceedings of this Conference intend to present and integrate reviews, advances and experiences on the different issues and aspects of agricultural water management and water saving while extending knowledge exchange from the Euro-Mediterranean region to other international contexts. In this regard, I believe the WASAMED Network has made every efforts to bring together all relevant local, regional and international key-actors and scientists to present and debate scientific contributions and to identify priorities in research and recommendations for relevant Mediterranean water policies through a multi-stakeholder discussion platform and a common vision document. Certainly, the best presumption for a successful discussion represents a sheer number of participants, more than 85 oral presentations, not only from the Mediterranean region but also from Central Asia Basin, Far East, and Central and North America, and numerous outstanding speakers. In view of that I truly deem that this meeting will contribute to the reinforcement of collaborative and cooperative relationships among the partners from the EuroMediterranean space, CIHEAM and European Union that would generate new initiatives to develop together in the region. In conclusion, I would like to express my sincere appreciations and gratitude to the European Commission INCO Program for its financial support and valuable work in following the progress of the project. Then, I would like to thank all WASAMED partners who have supported project coordination along the four years period and contributed to the successful implementation of the Conference. My deepest thanks go also to all the authors from 26 countries who have contributed to these three volumes and to the European Commission (General Directorate Research and General Directorate Agriculture), UN-Water, ICARDA, the Arab Water Council and the Apulia Regional Authorities for important keynote speeches. Finally, I would like to thank my colleagues 24 and staff of CIHEAM-IAMB for their help and support during the realization of the project and in the organisation of this event. I am sure they have made every efforts to create a comfortable and hospitable working environment at Bari Institute. I hope you will enjoy the Conference and your stay in Bari. Cosimo Lacirignola CIHEAM-IAMB Director 25 INTRODUCTION In the last decades, an increasing demand for fresh water resources has been posing a serious threat to environment and sustainable development in the arid and semi-arid countries world-wide and the competition for the use of such limited resources is growing dramatically among different sector. Water scarcity is more and more becoming one of the main restrictive factors of economic growth and social cohesion and a timely implementation of water policies and strategies that incorporate criteria of sustainability has become essential. This is particularly true for many Mediterranean areas where water shortage is among main constraints for agricultural development either under “rainfed” or “irrigated” conditions. Prospective of water saving in agriculture ranges from genetics to agronomic options, from engineering to economic and institutional solutions with a particular regard to the improvement of water use efficiency, better performance of irrigation systems, sustainable use of non-conventional waters, strengthening of the participatory management approach, adoption of appropriate economic tools and introduction of regular and standardized methods for monitoring and assessment of water resources availability, quality and consumption. The success of these options depends on the level of integration of technical, economic, institutional, environmental and cultural dimensions. In the Mediterranean, for example, water saving is still below expectations due to the lack of effective regional coordination, communication and dialogue among all the relevant stakeholders, and the difficulties to achieve a common-shared vision able to support the formulation of adequate national and regional water saving programmes and sustainable water policies. Regardless the type of water saving pathway, the most recent national and regional directives and on-field experiences have confirmed the integrated efforts in water saving, supported by national institutions and both regional and international organizations, as the best management strategy for sustainable development of agricultural sector. In this regard, the European Water Framework Directive is one of the most ambitious initiatives to achieve the sustainable use of local, regional and trans-basin waters through the integration of institutions, citizens and stakeholders in a participatory process of water governance. Moreover, in the last decade, the European Commission has promoted relevant research initiatives in the water sector in the Mediterranean region through the International Cooperation dimension of the RTD Framework Programme and, recently, launching the EU Water Initiative. In view of that, WASAMED project (WAter SAving in MEDiterranean agriculture) has been conceived and implemented with the main objective of establishing a platform for the effective Mediterranean dialogue on water saving in agriculture and contributing to a sustainable management of limited water resources in the Mediterranean Region. The 27 WASAMED Thematic Network, coordinated by CIHEAM-Bari Institute, accounts for a Mediterranean-wide country partnership based on 19 research institutions, 12 governmental agencies and institutions, 10 water user associations and 1 NGO from 16 countries: Algeria, Cyprus, Egypt, Germany, Greece, Italy, Jordan, Lebanon, Malta, Morocco, Palestine, Portugal, Spain, Syria, Tunisia, Turkey. In four years of the project, five International Workshops were carried out conveying more than 320 participants and resulting in more than 120 oral presentations. These Workshops have been organized respectively on: i) Participatory Water Saving Management and Water Culture (Sanliurfa, Turkey, December 2003); ii) Irrigation System Performance (Hammamet, Tunisia, June 2004); iii) Sustainable use of Nonconventional Water Resources (Cairo, Egypt, December 2004); iv) Water Use Efficiency and Water Productivity (Amman, Jordan, October 2005); v) Harmonization and Integration of water saving options (Malta, May 2006). The outputs of these events are synthesized in five technical-scientific proceedings including more than 60 country reviews and about 60 scientific keynote documents. Moreover, each workshop has included several technical working groups aimed at defining common criteria, goals and indicators of water saving in the Mediterranean agriculture. A total number of 15 working groups have been established throughout the five workshops, conveying a whole of about 150 participants from researcher institutions and universities, international organizations, governmental agencies and water user associations. The Conference on “Water saving in Mediterranean agriculture and future research needs” is the event completing the WASAMED activities. The Conference aims to bring together all relevant local and regional key-actors and scientists in order to discuss and identify the priorities in research to support national and regional strategies on water saving in the Mediterranean region. Accordingly, the Conference comprehends multi-stakeholder discussion platform as well as individual presentations of research findings, national reports and regional comparative studies on the following main themes: 28 state-of-the-art of research and on-ground implementation of water saving strategies and practices for improvement of: - Water Use Efficiency and Water Productivity, - Irrigation Systems Performance, - Use of Non-conventional Water Resources and - Participatory Irrigation Management and Cultural Heritage; integration and harmonization of water saving approaches at different scales, from field to irrigation district, watershed, national and regional basin: state-of-the-art and scaling up effects; socio-economic, environmental and institutional indicators for sustainable development of land and water resources and water saving in the Mediterranean region; policies and guidelines for conservation of land and water resources and sustainable water use at national and regional level and priority actions and innovative tools for water saving in the Mediterranean irrigated agriculture in spite of local and regional environmental conditions and expected socio-economic development and climatic changes. This number of “Option Méditerranéennes” consists of three volumes and includes 87 contributions presented in the Conference. These documents are grouped in six chapters – sessions (two in each volume). The first chapter is dedicated to the Water Use Efficiency and Water Productivity in agricultural sectors and consists of 21 contributions going from the country reviews to the results of experimental work related mainly to deficit irrigation strategies. The second chapter is committed with the Irrigation Systems Performance and Management and includes 12 papers related to both large scale and small scale irrigation systems. The use of Non-conventional Water Resources in Irrigated Agriculture is presented in the third chapter by means on both saline irrigation practices (7 papers) and application of treated wastewater (8 papers). Innovative approaches and tools for water saving are presented in fourth chapter by 12 papers that go from the application of recent information technologies and modelling and decision support tools to the on-ground experiments on rose cultivation by using local substrates in Cyprus. Fifth chapter is dedicated to Integrated Water Management considering both institutional, policy, social, economic and environmental aspects. This chapter consists of 19 contributions that covers a whole spectrum of themes: from participatory irrigation management to implementation of water pricing policies and mitigation of environmental problems. The last chapter is devoted to the EuroMediterranean cooperation and includes 8 papers, each of them representing one EU project actually going on in the Mediterranean region. We really hope this Conference, stimulating a constructive dialogue among scientists, relevant stakeholders and international organisations in ad-hoc discussion platforms, could represent a milestone in the establishment of an open and constructive dialogue among research, decision making and policy to strengthen a common EuroMediterranean as well International vision of agricultural water management and water saving in the region. WASAMED Coordination Team Nicola Lamaddalena (Project Coordinator) Claudio Bogliotti (Project Manager) Mladen Todorovic Alessandra Scardigno 29 SESSION 3: Use of Non-conventional Water Resources in Irrigated Agriculture USE OF NON CONVENTIONAL WATER RESOURCES IN IRRIGATED AGRICULTURE F. El-Gamal Director, Water Management Research Institute (NWRC), El-Kanater El-Khayria, Cairo, Egypt . Email : [email protected] SUMMARY Food security coupled with water scarcity is a cause of serious concern in almost all developing countries. The present over-use and degradation of water resources and growing competition of non-agricultural water users are expected to influence the cost and availability of water for food production. This situation is the root cause to spur special interest in non-conventional water use as an additional water source, particularly in the irrigated agriculture. However, the use of nonconventional water has a multidisciplinary nature with inter-linkage with environment, health, industry, agriculture, and water resource policy. In this regard, significant challenges still remain in the areas of technological, managerial and policy innovation and adaptation, human resources development, information transfer and social and environmental considerations. Sustainability and success of non conventional water uses depends on sound implementation and management. During the planning and management phases, the ecological, social and economic aspects should be considered in order to assure social and economic viability of any reuse activities. Further research is necessary to develop general guide lines, setting up a universal strategy and use systemic indicators for assessing, monitoring and evaluating the sustainability of nonconventional water reuse in the Mediterranean region. For sustainable and safe use of non conventional water, it is needed to provide the decision maker and the users with a concrete and very clear answer on how agriculture can make use of non conventional water resources in a way that is technically sound, economically viable and environmentally non- degrading. Key Words: Non conventional water, Drainage water , Water Scarcity , Waste water . INTRODUCTION Food security coupled with water security of many of the developing nations is a cause of serious concern. The natural resources base of land and fresh water per capita has been decreasing with the fast rate of rise of population. The increased demand of fresh water resources is a global concern, but for the Mediterranean region and particularly the arid and semi arid region, it becomes a serious challenge. Accelerated urbanization and industrialization in the Mediterranean are now opposing extreme pressure on the existing limited and vulnerable water resources. Meanwhile, agriculture activities are also geared to feed the ever-increasing population. These ambitious development activities tend to siphon off more and more water. Thus, water demand often exceeds reliable and exploitable water resources. Such existing imbalance between the limited water supply and the steadily increasing demand leads to serious conflicts over water and to the degradation of water quality in most of the countries of the region. Traditionally, the response to water shortage in the region has been addressed through developing more supplies. However, such traditional approach will be no longer adequate in the future. In the developing countries of the region agriculture sector is receiving the lion share of available water resources, about 80 percent. But the water use efficiency on the farm level is about 50 percent with losses around 50 percent. Such situation clearly emphasizes the central importance of demand management, particularly in the agriculture sector. Improving water use efficiency and increasing water productivity in the irrigation field means greater potentiality for water saving, this being the central issue to producing more food, fighting poverty, reducing competition for water and ensuring that there is enough water for the nature. Indeed, there is a high potentiality for water saving in the agricultural sector in the region. But, this will not be enough to overcome the prevailing water scarcity and to provide the increasing population with their food and fibre demands. 33 In the region, it is now a must to look for additional water resources that could be sustainable used in the agriculture sector. It is out of question that water availability for irrigation could be enhanced through the scientifically based use of non-conventional water. The uses of various types of non-conventional waters (urban waste waters, industrial waste waters, brackish waters / saline waters, and drainage waters) have been intensified in most countries in the region. However, even though its re-use and recycling can appear like a simple and appropriate technology, in reality it is a complex one. The use of non-conventional water has a multidisciplinary nature with inter-linkage with environment, health, industry, agriculture, and water resource policy. To attain full utilization of this vital water source, one has to find sound solutions to several obstacles still hampering the sustainable and safe use and recycle. In this regard, significant challenges still remain in the areas of technological, managerial and policy innovation and adaptation, human resources development, information transfer and social and environmental considerations. Achieving the goals needs the using of tools available today from the scientific, technological, legal, political and economic framework. This required concerted efforts supported by national institutions and both regional and international organizations TECHNICAL- TECHNOLOGICAL DEVELOPMENTS OF NON-CONVENTIONAL WATER USE Human use of fresh water has increased more than 35 times over the past three centuries. The st experts predict a severe shortage of fresh water in the 21 century. More than 230 million people living in some 26 countries, 11 of them in Africa and 9 in the near east will suffer from water scarcity 3 (less than 1000 m per person per year). In the Mediterranean region, particularly the southern and eastern countries, it is quite apparent that some of those countries are now already under severe water stress, and within the next twenty years, it is expected that most of the countries of the region will be under absolute water stress. The available water per capita per year will amount to few hundreds cubic meters (Fig. 1). 1200 Water Supply 1000 m 3/year / inh Egypt Morocco 800 600 Algeria Tunisia 400 200 0 Jordan Lybia 1985 1990 1995 2000 2005 2010 2015 2020 2025 Year Fig. 1. Available Fresh Water Per Capita per Year for some Arab countries For the Mediterranean countries, the non conventional water resources of varying quality including saline water, drainage water and waste water with varying qualities could play an effective role in mitigating water scarcity, particularly in the irrigation sectors. This is not only due to the opportunity they could provide to increase the irrigated area and food production, but, also to the fact that they are 34 a renewable resource and are subjected to continuous increments with time, besides being present in relatively big quantities as high as nearly 10 percent of the whole available freshwater in the region. However, the full use of this source for irrigation requires that certain measures be carefully considered to guarantee its save and sustainable use. The complex interaction of water, soil and crop in relation to water quality must be well understood. The technology and concepts of using and managing the non-conventional water in irrigation must be available and well developed for sustainable production on permanent economic basis. It requires the development of new scientific practices, new guidelines for use that cope with the prevailing local conditions and new strategies that facilitate its use on a relatively large scale. Aware of these complex inter-linkages, the sustainable use and achievements of maximum benefits of non conventional water resources, as a freshwater saving practice still require further development including planning, investigation, monitoring and management. Over the last five decades and more, many research scientists, organizations, institutions and authorities have advocated the concept of using saline water for irrigation to increase food production. Considerable amounts of such water are available in various countries of the regions, but, they are still marginally practiced in irrigation, although they could be successfully used to grow crops without long term hazardous consequences to crops or soils by applying improved management practice. Globally, there are around 43 countries, mostly from arid and semi arid regions, are using saline water for irrigation. The southern Mediterranean countries are practicing saline water in irrigation purely by necessity rather than by choice. There are successful examples in using non-conventional water in Irrigation in the Mediterranean regions: 3 In Egypt, about 5 thousand millions m of saline drainage water is used for irrigating about 405,000 ha of land, Table 1. About 75 percent of the drainage water discharged into the sea has a salinity of less than 3,000 mg/l. The policy of the Government of Egypt is to use drainage water directly for irrigation if its salinity is less than 700 mg/l; to mix it 1:1 with Nile water (180 to 250 mg/l) if the concentration is 700 to 1500 mg/l; or 1:2 or 1:3 with Nile water if its concentration is 1,500 to 3,000 mg/l; and to avoid reuse if the salinity of the drainage water exceeds 3,000 mg/l. The annual 3 average volume of available drainage water is about 14 thousand million m . The policy of the ministry of water resources and irrigation is to make full use of each drop of drainage water by the year 2017, Table 2. Some large scales projects are currently executed depending on the drainage water as the main source for irrigation. Table 1. Reuse of Drainage Water in the Nile Delta during 1995/2003 Year Eastern Delta Middle Delta Western Delta Total Reuse Q EC Q EC Q EC Q EC 1995_96 1745.9 1.89 1814.6 1.79 705.9 1.42 4266.3 1.77 1996_97 1843.2 1.94 1947.9 1.85 642.5 1.31 4433.6 1.81 1997_98 1736.3 1.66 1801.3 1.77 632.4 1.35 4170.1 1.66 1998_99 2126.9 1.48 2168.3 1.52 738.3 1.07 5033.5 1.43 1999_00 1661.8 1.64 1891.4 1.64 1183.6 1.97 4736.8 1.72 2000_01 1830.2 1.57 1958.8 1.76 1058.3 1.92 4847.3 1.72 2001_02 2026.5 1.74 2199.8 1.67 1062.8 1.76 5289.1 1.71 2002_03 2329.3 2.00 2082.4 1.90 875.6 1.76 5287.4 1.92 3 Q: Drainage water Discharge (million m / month) EC: Drainage water salinity (ds / m) 35 Table 2. Maximum Possible drainage water reuse in Nile Delta (million m3) Region Available Drainage Water Currently Reused Possible to be reused Eastern Delta 4083.65 2049.89 1519.02 Middle Delta 5849.14 2007.73 2881.06 Western Delta 3819.15 1123.56 2384.33 Total 13751.94 5181.18 6784.41 The techniques and technologies used in drainage practices are under continuous development on a well established research base. The development and verification of design drainage criteria for local conditions are always a concern with the progress of drainage projects to cover new areas. Pilot areas are designed and implemented for meeting specific changes in the hydrological, soil or cropping conditions. A dynamic monitoring programme to validate the accuracy of the used criteria is essential. A modern computerized data base was established to store all relevant collected data and information. The introduction of an integrated water management approach is the most reliable procedure for water resources management. Much research work has been and still being carried out to improve drainage implementation including testing and evaluation of new materials and machinery and the adoption of new techniques to cope with the local conditions. Equally, emphasis is given to determine the effects of the re-use of drainage water in irrigation on soils and their productivity for a range of crops. The environmental impacts are carefully monitored and investigated. Health and ecological measures are of concern. Social aspects, particularly those related to women as important users of water are progressively coming to the centre of attention. Egypt has a policy to use brackish and saline ground water with EC up to 4.5 ds/m and reuse of drainage ground water with EC 6ds/m with SAR values of 10 to 15 in blending or cyclic mode with good quality water. The reuse of treated waste water in Egypt started in 1915 in the eastern desert north east of Cairo. An area of 2500 acres is still under irrigation with waste water, which receives only primary treatment. With the scarcity of water resources, it is planned to irrigate 150 thousands acres with treated waste water. All urban waste water projects include facilities for treatment up to the tertiary level and allow reuse for irrigation. It is estimated that present amount of waste water from 3 major cities and urban area is about 5 billions m /year. Currently, detailed criteria for waste water reuse in agriculture are under review and preparation. Several pilot programs have started and under continuous monitoring for some refinements. In Morocco, there are approximately 7.7 millions hectare of arable lands, of which one million hectare is actually irrigated and the rest is under rain fed agriculture. However, poor soils physical conditions, soil salinity, water quality and water stress are considered major limitation for agriculture development. Rational use of irrigation water, by adopting adequate drip irrigation for high value cash crops and the use of supplemental irrigation is widely recommended to stabilize and to improve crop yield. However, with the scarcity of high quality water resources, the use of non- conventional water is not only a necessity, but also an inevitable option to alleviate the water crisis. The potential of waste water is shown in Fig.2. 900 Volume in Mm3 900 800 666 700 600 495 370 500 400 270 300 200 100 0 48 1960 129 1970 1980 1990 2000 2010 Year Fig. 2. The potential of waste water in Morocco 36 2020 In Agadir region, sand infiltration system is used to treat its waste water to be reused in agriculture and landscaping. This technology generates high nitrate concentration in the effluent. To face the salinity problem and to diminish its hazards negative effect on both soil productivity and crop production, an ample research programme was conducted to establish an appropriate land, water and crop management under saline irrigation practices. The contribution of the farmers in facing the salinity problem, through improving the local technologies, cannot be denied. The knowledge and the experience gained from the research work indicated that the cultivars, the growing media, the climatic conditions and the salt level of irrigation all affect the final yield. The experience of Morocco on the use of saline water as an irrigation source clearly indicates the high potentiality in its use if proper management is developed for specific crops under specific climatic and soil conditions. The learned lessons of this experience is that salinity problems could be faced and sustainable solution could be attained by improving the local technologies the farmers are using by introducing simple techniques such as stage of planting, selection of cultivars, application of organic manure, modified soil media. Such simple techniques can have a greater impact on the marketable yield and quality of the product. In Algeria, the possibilities of using drainage water with a relatively high salt concentration level (9 ds/m), SAR value (15.7) and PH of 8 were experimented for the development of salt lands in Biskard area, southeast of Algeria. The drainage water is an important source for the irrigation of palm 3 trees due to its presence in relatively high quantities exceeding 3 millions m / year. The experience demonstrated the successful use of drainage water in irrigation through an appropriate irrigation and leaching scheduling, the addition of soil amendments to avoid soil sodicity, the selection of the palm trees varieties as well as the irrigation method. The availability of substantial quantities of drainage water offers the best guarantee for increasing the irrigated area in south of Algeria. 3 3 In Tunisia, the water resources is about 4.5 billion m , of which 2.7 billion m of surface water and 3 1.8 billion m of ground water. It is expected that by year 2020, the domestic and industrial demand will increase and the available water for agriculture will decrease. In order to overcome this problem and provide the different sectors with their needs, management, conservation of existing water resources and development of non-conventional water source have been developed in the field of water planning and management. Water and soil salinity is a major constraint for Tunisian agriculture development. Salinity problems and saline irrigation practices and management have been intensively investigated since 1970. The experience gained helped in improving the agricultural productivity under saline environment and setting up the needed guide lines and management techniques to be practiced for save and sustainable use of saline water in irrigation. The saline Medjerda river water (annual average EC of 3.0 ds/m) has been used to irrigate date palm, sorghum, barley, alfalfa, rye grass and artichoke. The soils are calcareous (up to 35% CaCO3) heavy clays, which crack when dry. Waste water reuse is now an essential component of the Tunisian national water resources strategies and an integral part of overall environmental pollution control and water management strategy. The waste water reuse policy was launched at the beginning of the 1980. Of the 237 million 3 3 m of waste water discharged annually, 123 million m are treated in 52 treatment plants. Within the next ten years, this amount is expected to increase by 50%. The policy aims at extending waste water treatment to all urban areas. The reclaimed waste water is used for irrigation, tourist areas, to irrigate golf fields and hotel parks. Also, it is used in groundwater recharge and industry. In Greece, water resources are limited temporally and spatially. The total water consumption, in 3 1990, was 5500 millions m / year. It increases by more than 3 % annually. The major water use is irrigation with a percentage of 85 %, while domestic use is 11 % and industrial use is about 4 %. The continued increase of domestic and irrigation water demand can only be met through an integrated water management scheme that includes the use of all sources including non-conventional waters. Imbalance of water demand and water supply is often experienced, especially in the coastal and south eastern regions, due to temporal and spatial variations of the precipitation, the increased water demand during the summer months, and the difficulty of transporting water due to the mountainous terrain. 37 Today, there is 350 municipal waste treatment plants can serve about 65 % of the country population. By reusing the effluent of the existing plants, the reused water, particularly for irrigation of agricultural land, can be increased by 3.2% of the current total use of freshwater. Thus, the freshwater that is currently used for irrigation can be saved. This percentage will be substantially increased as the number of municipal waste treatment plants increase. In Cyprus, the water scarcity together with the high cost associated with collecting and using the limited surface rain water for irrigation, has become real constraints. Therefore, alternative water resources, innovation approaches and new technologies are sought to help solving the problem. Development of more efficient irrigation methods to save water by better utilization, irrigation with saline water and reclamation and use of treated municipal waste water, are promising alternative and innovative approaches. By irrigating with modern irrigation systems, crops are grown successfully and higher yield is obtained with more saline waters. Experimental data and experience gained suggested that with proper irrigation and fertilization management, some problems associated with salinity can be alleviated and occasionally overcome by recurring to crops that are semi- tolerant or tolerant to salinity. The municipal treated effluent is considered as integrated part of the water resources. It is assumed that 6% of the cultivated land could be irrigated with municipal treated effluent. In Jordan, irrigated agriculture consumes 70% of the water available, competing with the rapid growth of urban and industrial demand. Therefore, saline water is a highly valuable source of water for irrigation. A major challenge to agriculture is the optimal utilization of brackish water and treated waste water without causing adverse effects to the environment and at the same time reducing the amount of fresh water consumption for food production. It is expected that within the next twenty years, the proportion of non- conventional water will be more than 30% of the total available water resources. The amount of waste water reused in agriculture in the Jordan valley increased from 20 3 3 million m in 1990 to 42 million m in 2002. It was projected that the reuse of treated waste water will 3 reach 60 million m in 2002. Research findings regarding crop production indicated that for sweet corn, irrigation with saline water of less than 3.5 ds/m has not caused significant reduction in yield. The tolerance threshold of soil salinity for relative yield of union varies from 2.43 to 3.6 ds/m. The drainage water is used for irrigating garlic and onion with careful management. Brackish water with salinities ranging between 3-11 ds/m is used in the southern Jordan valley. The experience gained indicated that yield production will differ from to another according to crop salt tolerance degree. A limiting factor for using brackish water in irrigation is the salt accumulation in the soil. Therefore, available fresh water for leaching is required. Another solution is the alternation irrigation, fresh water is used during the sensitive germination and emergence stages until the crop stand is established, then, irrigation is practiced with saline water. In Syria, non-conventional water resources are restricted to wastewater (drainage water, wastewater). Agricultural sector is the largest consumer of conventional and non-conventional water 3 resources. Wastewater amount is about1.2 billion m /year and drainage water is about 1.536 billion 3 m /year. About 29.2% of wastewater is treated, 34.6% is used without treatment, and 36.2% is lost by discharge to water bodies and valleys. There is a need for establishing treatment plants at small community level with population (5000 – 10000) to make use of water randomly lost and contaminating the environment. There is a lack of crucial local criteria for wastewater use in agriculture. The existing criteria are merely indicators and preliminary guidelines that can be developed through research activities. There is a number of environmental, health and economic problems as a result of improper and irrational use of wastewater are already exist. The essential pre-requisites for the development of safe nonconventional water use lie in the development of institutional and legislative aspects together with training, information and others. There is a need to implement some pilot projects for the optimal utilization of conventional water and giving top priority to the most critical and urgent issues. Also, Supporting scientific and research centers and institutions for conducting integrated and applied water research and studies is required, since these centers and institutions are an integral part of the institutional structures responsible for water resource development and utilization. Training of technical and scientific staff and giving special consideration to skill upgrading, performance promotion and capacity improvement. 38 In Lebanon, the total available water resources is about 2000 millions m3. The total need, in 2020, 3 is estimated as 2450 millions m . This imbalance will force the country to search for new nonconventional water resources. Waste water is the only suitable source for additional water due to economic constraint. A master plan for secondary waste water treatment is already elaborated for all Lebanon and Funded at 70.47 % of total Cost. Between 2005 and 2007, constructed plants are previewed to serve, until 2015, 88% of the total Lebanese population. The possible collected waste 3 water for treatment, in 2020 is about 250 millions m . In Turkey, The total available water resources are about 108.66 billion m3, (surface water is about 3 95 billion m and ground water potential is about 13.66 billion m3). The irrigable area is about 4.3 millions hectare (16.6 % of the total irrigable land). It is estimated that, only 8.5 millions hectare can be irrigated with the present water resources. When all irrigable lands are opened to irrigation, roughly 200 km3 more water is going to be required. Therefore, the solution was to apply the deficit irrigation programmes including supplemental irrigation and to manage the irrigation systems according to deficit irrigation approach and to find the new water resources. Unconventional water such as brackish water (treated waste water, drainage water), shallow ground water and saline water must be used in near future. 3 The estimated waste water, urban and industrial in 2001, is about 6.7 billions m . The collected water looks like to complete the little part of the deficiency of water resources. The diluted sea water seems to be the only way in future. Some experiments have been carried out using saline water for irrigation. The results from experiments showed that saline water decreases the yield and quality of all the plants. However, the data and information regarding the use of unconventional water in irrigation, for a lot of crops grown in the different region of Turkey, were obtained and the studies are being continued. SOCIOECONOMIC, ENVIRONMENTAL, INSTITUTIONAL AND POLITICAL ASPECTS FOR NONCONVENTIONAL WATER USE In most of the Mediterranean countries, the highest portion of the water resources is allocated to the agriculture, mainly being for irrigation. Non conventional water could relieve as a substitute for freshwater in irrigation. However, implementation of non-conventional water in irrigation is still a big challenge due to the complexity of the systems. Planning and management of agricultural reuse operations need to take into account the socio-economic, institutional, organizational, legal, regulatory, environmental and technical aspects. Reusing agricultural drainage water implies an increase of global irrigation efficiency, but also entails the degradation of the water quality, which affects the soil properties, reduces crop yield and pollutes the flows returned to the hydrological ecosystem. Also, Reuse of treated and untreated waste water in irrigation has a high positive potential to environmental relief and social and economic development. But, reusing waste water without good planning can cause soil quality problems in the long run, due to building up salinity and heavy metals. It also results in health risk due to the exposure of farmers, consumers and neighbouring communities to infectious diseases. Therefore, the various factors of risk must be converted into actions of attenuation and regulations associated to good practices. The code of good practices of reuse, all as standards of quality, must be developed and adapted to take into account the specific local conditions. Agriculture use of non conventional water is more easily accepted and implemented in water-short areas where irrigation is already practiced. However, skills development, appropriate institutions and strong extension services are required. Participatory bottom up approach is a cornerstone issue governing success and/or failure in any reuse irrigation project. Water user associations should be involved and associated in the planning and management process to ensure the success of the project. The farmers usually succeed in developing appropriate strategies to make the best use of the available water in order to maximize the agriculture production. Finally, sustainability and success of non conventional water uses depends on sound implementation and management. Poor planning and management might bring high health and environmental risks, and undesired economic and social results. During the planning and 39 management phases, the ecological, social and economic aspects should be considered in order to assure social and economic viability of any reuse activities. GAPS AND ACHIEVEMENTS Non conventional water is well recognized, in the Mediterranean region, as an alternative source of irrigation water. Many researchers and scientific institutions have intensively investigated the use of non conventional water in irrigation and the way to practice and manage it. The information, the experiences globally gained and the findings of research, all resulted in a notable development on the use of non conventional water for irrigation and demonstrated its high potentiality for use. In Italy, Bari institute and many other research institutes and universities are giving the non conventional water resources practices and management the priority in their research programmes. Bari institute has intensive research programme on the use of saline water for irrigation. The experience gained demonstrates that saline water can be used effectively for the production of selected crops under the right conditions. In Egypt, intensive research programme together with field experiments have been carried out for reusing agriculture drainage water. Monitoring and evaluation program are under continuous developments on a well- established research base. Guidelines for optimal use of drainage water and setting up strategies for reuse, under the Egyptian conditions have been delivered. In Morocco and Tunisia, intensive research programme for the use of treated waste water in irrigation. The finding of the program demonstrates the suitability of reuse of treated waste water in irrigation when appropriate practices are adopted. In fact, Important and useful research on the potentials and limitations and hazards of the use of non conventional water in irrigation were undertaken in relative isolation and no mechanism existed for coordinating the research work and to utilize effectively the research findings. There is no universal approach to achieve salinity control in irrigated agriculture; it varies from country to another. It depends on economic, climatic, social and hydro-geological conditions. The further research will have to give more attention in the following areas: Defining policy and strategy on the use of non conventional water in irrigation. To arrive at these policy and strategy, monitoring programs are required on both water quantities and qualities, as well as on soils properties; Integrated management of water of different qualities at farm level, irrigation system and drainage basins with the explicit goals of increasing agriculture productivity, achieving optimal efficiency of water use, preventing on- site and off- site degradation and pollution, and sustaining long term production potential of land and water resources; Developing and use of mathematical models to relate crop yield to irrigation management under saline conditions so that empirical models can be reliably applied under a wide variety of field conditions; The trade-off between provision of full drainage and drainage volume reduction; The incorporation of salinity into groundwater flow models to predict the development of not only water logging but also of soil water salinity. Regional agro-hydro-salinity models should be of immense value in planning appropriate water management strategies; Activating the role of policies and institutions in creating demand for technology to ensure the sustainability of irrigated agriculture in saline environment; Conducting a comprehensive and coordinated research on potentials and hazards of the use of non conventional water for irrigation; 40 Establishing working relationship on national, regional and international institutions dealing with the reuse of non conventional water through the formulation of networks; Conducting and fostering a comprehensive multi-disciplinary basic and applied research programme in coordinating fashion on the sustainable use of non conventional water in irrigation and related problems and obstacles; Providing facilities for research workers and improving the Institutional Capacity Building; Incorporation of environmental, Institutional, political and social and economic concerns. Further research is necessary to develop general guide lines, setting up a universal strategy and use systemic indicators for assessing, monitoring and evaluating the sustainability of nonconventional water reuse in the Mediterranean region. IDENTIFIED PRIORITIES Non conventional water is a potential source for additional water to be used in irrigation. But, in the long run, it could seriously affect the crop production; deteriorate the soil productivity and creating serious environmental problems and health risks. Therefore, during the reuse practices a monitoring program has to be apply, to identify areas with environmental and health risk as a result of low water quality. It is the first step towards identifying priority actions that will reduce the health risks. In some areas short term action may be required to change the practices mechanism, but always the longer term actions that will reduce the pollution and enhance the reuse potential are still required. The short term actions can be separated into pollution control actions and protection actions. Pollution control actions are measures to reduce the non conventional water in areas that are already polluted. Protection measures are measures to prevent vulnerable areas to be polluted in the future. In general, to enhance the reuse potential the various factors of risk must be converted to actions of attention in the following fields: Planning • • Strengthen the participation of the beneficiaries Monitoring the quality of non conventional water and reinforce existing regulation Economic Aspects • • Establish cost-beneficiate analysis Insure that reuse policy is profitable to the farmers Organizational Aspects • • Encourage cooperation between different institutions Establish services contacts between the manufacturing institution and local expertise institution Regulation Aspects • • Establish norms and standards for the reuse of non conventional water Limit the parameters to be monitored 41 Technical and agronomical Aspects • • • Encourage the drip irrigation system Optimize the recycling of the nutrient elements included in the water Develop a strategy for the storage of wastewater Sanitary Aspects • • • Develop analytical methods for monitoring persistent contaminants Improve research techniques for parasites and virus Develop a methodology and monitoring evaluation system of the impact of the reuse on the soil, crops and ground water. Awareness arising • • Establish awareness and education programs for farmers, engineers and technicians Develop handouts on different aspects of the reuse of non conventional water. RECOMMENDATIONS The continued increase of domestic and irrigation water demand can only be met through an integrated water management scheme that includes the use of all sources of water including nonconventional waters. Non conventional water such as (brackish water, treated waste water, drainage water, shallow ground water and saline water) is a potential source in several countries and there is a wide experience in the Mediterranean region for using it in irrigation as fresh water saving practices. The complex interaction of water, soil, plant, and climate condition, in relation to water quality should be considered when using non conventional water in irrigation. Water management strategies should establish when using non conventional water to minimize the negative impact on environment and soil productivities. The management strategy should include efficient use of water (not excessive), sustainable and save use of water, suitable irrigation system and suitable crop (salt tolerant level matches the salinity level). Efficient water use would minimize drainage volume and rising water tables which is an environmental problem Monitoring and evaluation programme should be carried out for water quantities and qualities, as well as soil’s salinity. Socio- economic, institutional, political, ecological, health and environmental aspects are to be taken into consideration by decision- makers when considering using non conventional water resources for irrigation. Cost recovery is an essential requisite to ensure the economic sustainability of the use of nonconventional resource. Supporting scientific and research centres and institutions for conducting integrated and applied water research and studies since these centres and institutions are an integral part of the institutional structures responsible for water resource development and utilization Encouraging the establishment of networks between scientific and research centres on using non conventional water. Farmer’s participation in the planning and management is a key for the safe use of non conventional water in irrigation. Involvement of the farmers in the exercise will close the knowledge gap between farmers and researchers. 42 Further research is needed on integrated water, crop and land resources management to safely and sustainable use of non conventional water. Use of mathematical Models should be encouraged to predict long term salinity impact on soil, plants and the environment. REFERENCE Abdel- Azim, R. And Allam, M.N. (2004). Agricultural drainage water reuse in Egypt: Strategic issues and mitigation measures, Non conventional water use workshop, Cairo, Egypt. Abu Zeid, M. A., (1997). Egypt’s Water Policy for the 21st Century, IXth World Water Congress of IWRA – special session on water management under scarcity conditions– the Egyptian Experience, pp. 1-7, IWRA, Montreal, Canada. Choukr- Allah, R. (2004). Wastewater Treatment and Reuse in Morocco: Situation and Perspectives, Non conventional water use workshop, Cairo, Egypt. Duqqa, M., Shatanawi, M.R. and Mazahrih, N., 2004. Reclaimed Wastewater Treatment and Reuse in Jordan: Policy and Practices, Non conventional water use workshop, Cairo, Egypt. Gunther, D. and Ozerol, G. (2004). The Role of Socio-economic Indicators for the assessment of Wastewater Reuse in the Mediterranean Region, Non conventional water use workshop, Cairo, Egypt. Hamdy, A., (2004). Evidence of the Potential Use of Saline Water in Irrigation as Fresh Water Saving Practice. Non conventional water use workshop, Cairo, Egypt. Hamdy, A., (2004). Non conventional water resources practices and management, Non conventional water use workshop, Cairo, Egypt. Hamdy, A., (2004). Saline irrigation management for a sustainable use, Non conventional water use workshop, Cairo, Egypt. Kaisi, M. Yasse and Y. Mahrouseh, (2004). Syrian Arab Republic Country Report, Non conventional water use workshop, Cairo, Egypt. Kanber, R., Unlu, M. 2004. Unconventional Irrigation Water Use in Turkey, Non conventional water use workshop, Cairo, Egypt. Karaa, K., Karam, F. and Tarabey, N., (2004). Wastewater Treatment and Reuse in Lebanon: Key Policies and Future Scenarios, Non conventional water use workshop, Cairo, Egypt. Karamanos, A., Aggelides, S. and Londra, P., (2004). Non-conventional Water use in Greece, Non conventional water use workshop, Cairo, Egypt. Mostafa, H., El Gamal, F. and Shalby, A. (2004). Reuse of Low Quality Water in Egypt, Non conventional water use workshop, Cairo, Egypt. Quarto, A. and Meroz,Y. (2004). Socio-economic Evaluation of Reuse Project and Pricing Policies for Wastewater, Non conventional water use workshop, Cairo, Egypt. 43 WATER SAVING POTENTIALITIES THROUGH THE USE OF SALINE WATER AND THE APPLICATION OF DEFICIT IRRIGATION * * ** *** **** A. Hamdy , N. Katerji , M. Mastrorilli and A. Dayyoub Professor Emeritus, CIHEAM-Mediterranean Agronomic Institute of Bari, Italy E.mail: [email protected] ** INRA, Station de Bioclimatologie, Thiverval-Grignon, France *** Istituto Sperimentale Agronomico, Bari, Italy **** Meditarranean Agronomic Institute of Bari, 70010 Valenzano (BA), Italy SUMMARY- This work was conducted in the greenhouse of the Mediterranean Agronomic Institute of Bari, aiming to have further information characterizing the response of different durum wheat varieties to saline irrigation practices (5 and 10ds/m) using different irrigation regimes (100%, 60% and 40% of Etc). The presented data indicate clearly that the resistance to salt stress, as well as water stress varies greatly due to the variation in the studied wheat varieties. The findings show also that the vegetative growth and the grain yield production can tolerate salinity up to 5ds/m, which could be raised up to 10ds/m resulting in only 10% losses in the grain production. As a result, the apparent losses in the yield production under deficit irrigation using the saline water is fundamentally attributed to the water stress conditions. However, deficit irrigation with an appropriate Etc percentage and irrigation salinity level, is a win-win game as it provides good fresh water saving, acceptable yield production besides maintaining the soil salinity relatively low. INTRODUCTION In the arid and semi arid countries of the Mediterranean, the limited natural resources (land and water) in addition to the increase of population at a relatively high rate averaging to nearly 3 to 3.5% annually are putting immense difficulties for most of those developing countries to achieve water security, food security and environmental sustainability. In spite of the major effects and the intensive programs carried out in those countries to improve the water productivity and water use efficiency in all water sectors particularly in the irrigation one, many countries are still far a way from achieving the goal of food security and water security (Hamdy and Katerji, 2006). One of the approaches to be highly recommended is the use of the non-conventional water resources (saline brackish water and treated municipal waste water) as an additional water resources for irrigation to overcome the big gap in the cereals production (wheat, barley, maize), which are the fundamental crops having an important role on food security, fighting the poverty and alleviating hunger and mal nutrition. Indeed 60% of cereals are produced under rain-fed agriculture conditions. This production is relatively low; representing nearly 20% of the one could be produced where irrigation is practiced due to the prevailing drought conditions at the critical growth stages (flowering and seed formation). Under such conditions there is a high potentiality to improve cereal production through supplemental irrigation at the critical growth stage with water having relatively high salt concentration level as most cereals can tolerate an Eci value lying between 6 ds/m and up to 8 ds/m. Aware of the importance of the subject for most of arid and semi arid countries in the MENA and the Mediterranean region, an ample research program started 5 years ago between CIHEAM-IAMBari, ICARDA, INRA France and Agricultural university of Wageningen Holland where a part was directed to leguminous crops and other to the cereal crops in order to identify and distinguish between the different crop behaviors concerning their salt tolerance degree, in order to select the appropriate varieties with a higher salt resistance as a recommended varieties in the region. 45 The studies included in the research program were carried out in drainable Lysimeters and under controlled conditions in the IAM-Bari greenhouse, and covered the Leguminous crops, Beans, Check bees, Lentils and the cereals Barely, Durum Wheat and Bread Wheat. The work presented in this study is a continuation of the research program, but the new in this research that it is not limited to elucidate just the impact of salinity, but also the effect of drought and water stress on the different plant growth stages and the yield. The work presented in this paper is a part of this ample research program which has been carried out by the Mediterranean Agronomic Institute of Bari with INRA France and ICARDA, where, several varieties of durum wheat supplied by ICARDA will be under investigation with the main objectives of Investigating new ways of using the saline water for wheat production under arid and semi-arid conditions focusing on the salt tolerance degree of the durum wheat varieties, also to elucidate the behavior of the wheat growing parameters and the production under variable water stress and salt stress conditions. MATERIAL AND METHODS The experiment was conducted in the greenhouse of the Mediterranean Agronomic Institute in Valenzano, Bari (eastern south coast of Italy), during the year 2005-2006. The greenhouse where the experiment was conducted is covered with fiberglass sheet and is equipped with aeration and heating systems, thermostatically controlled to keep the temperature constantly around 20°C. The experimental trail included two major parts: ¾ The first, where soils were kept during the whole cropping period at field capacity. At each irrigation the volume of water applied corresponds to the depleted water due to evapotranspiration. ¾ The second, where the plants were subjected to deficit irrigation receiving at each irrigation a volume of water equal to 60% and 40% respectively of the water lost due to evapotranspiration. Following variables were studied: • • • Durum wheat: three varieties under investigation (Table 1). Three salinity levels for irrigation water: fresh water of EC 1ds/m (control treatment) and two salinity levels 5ds/m and 10ds/m. Three irrigation regimes: ¾ 100% of evapotranspiration (Trial A) ¾ 60% of evapotranspiration (Trial B). ¾ 40% of evapotranspiration (Trial B). Table 1. Agronomic characteristics of the investigated cultivars tested in the green house. Symbol Name Origin Some agronomical characters V1 CHAM -1 CIMITICARDA High yielding, good performance under higher rainfall and supplementary irrigation V2 HAURANI Syria Landrace V3 HUGLA ICARDA Showing salt tolerance Source: ICARDA, plant breeding sector. 46 Table 2. Chemical analysis of irrigation water Soluble anions (meq/l) Soluble cations (meq/l) EC (ds/m) pH F.W 7.35 3.70 1.20 6.80 7.20 2.80 1.57 0.13 0.70 5.00 7.52 3.25 21.30 15.20 7.10 11.30 21.70 1.16 6.85 10.00 7.41 3.60 46.80 27.11 7.40 22.40 45.71 2 11.84 - HCO3 -- CL- SO4 Ca++ Mg++ Na+ K+ SAR The set-up consists of 162 lysimeter, made of polyvinyl chloride (PVC) with a volume of 0.07m3 (diameters of 0.40m and depth of 0.60m). The bottom of the tube was sealed with plastic tent 0.2 mesh in diameter and placed at the bottom of lysimeter 5 cm of coarse gravel for maintaining the proper drainage. At the upper part of the lysimeter depth of about 10-cm was left empty for the accommodation of irrigation water. Three porous cup tubes were located at different depth (15,30 and 45 cm) for soil water sampling by suction. Each lysimeter was placed inside a plastic container to collect the drainage water. The lysimeter dimensions and its technical specification are illustrated in Fig.1. Porous cups Diameter 40 cm 15cm Length 60 cm 30cm 45cm Reservoir Drainage Fig. 1. Scheme of Lysimeter with Porous cups and drainage reservoir Surface irrigation system was used before sowing; the volume of the water needed to bring the contained soil in the lysimeter to field capacity was calculated using the irrigation indicator lysimeter line. After sowing each lysimeter was irrigated with a constant volume of water previously calculated. To ensure a good germination percentage and healthy well developed seedling both stages were performed using fresh water. Irrigation with saline water started at the end of seedling establishment stage where seedling thinning took place. Irrigation was practiced when 30% of the available water was depleted due to evapotranspiration; this was calculated by the aid of a class A pan installed inside the green house. To calculate the volume of water to be applied at each irrigation to compensate the water losses due to the evapotranspiration, one replicate of each treatment “the irrigation guide line “at the irrigation time was watered, and the excess drained water accumulated in the bottom the plastic container was 47 collected and measured. Differences between the applied water and that sucked from the plastic container gave the amount of evapotranspiration corresponding to water amount to be applied at each irrigation practice for the rest of application. Such technique was followed for both fresh water (control treatment) and the saline irrigation treatment (5 and 10ds/m). The volume of water calculated under each investigated salinity level was added in full to the 100% irrigation trial, where as for the deficit irrigation trials only 60% and 40% of the volume was applied After complete maturity of wheat the plants were harvested and divided into four main parts (roots, shoots and grains). The plant components were oven dried at 70ºC for 48 hours and the oven dry weight were recorded for each replicate in the investigated treatment. Immediately after harvesting, representative soil samples were taken from the upper layer (0-15 cm), from the intermediate layer (15-30 cm) and from the bottom layer (30-45 cm). All soil samples were analyzed for their salt content. RESULTS AND DISCUSSION Water saving potentiality under deficit irrigation and irrigation with saline water One of the major constraints, most arid and semi arid countries particularly those of the Mediterranean are now facing for achieving food security and agricultural development, is the chronic shortage in the available water resources. The increase in population at a relatively high rate, the very rapid urbanization on one hand, and the economical industrial development on the other hand, all are now raising up further problems beside the complex one, already are existing. The policies of most of those countries in achieving both water and food security in their countries is mainly directed towards improving the management and use of water in agricultural sector which consumes more than 80% of the available water resources, but with a relatively high water losses and very poor water use efficiency not exceeding the 50%. Politically and technically, it is now well recognized that the key in solving the water problems lies in the agricultural sector through improving crop water productivity, avoiding water losses and increasing the irrigation water use efficiency. However, this to be achieved necessitates the implementation of effective programs for water saving in the agricultural sector. Indeed, there are several approaches for water saving in this sector, among them the deficit irrigation practices and the use of the non conventional water resources, the saline one as an alternative water source for irrigation. The question is what is the potentiality of water saving in the agricultural sector using such approaches? The volumes of water applied during the whole cropping period under the different irrigation regimes using water of different salinity levels in both A and B trials are presented in Table 3. 48 49 V1 V2 V3 Avg. V1 V2 V3 Avg. V1 V2 V3 Avg. FW FW SW (m3/ha) (m3/ha) Tot. 3991.0 0.0 3991.0 4344.8 0.0 4344.8 4247.9 0.0 4247.9 4194.6 0.0 4194.6 Trial B - 60% irrigation FW FW SW (m3/ha) (m3/ha) Tot. 2593.2 0.0 2593.2 2868.2 0.0 2868.2 2587.0 0.0 2587.0 2682.8 0.0 2682.8 Trial B - 40% irrigation FW FW SW (m3/ha) (m3/ha) Tot. 2451.9 0.0 2451.9 2157.5 0.0 2157.5 2144.5 0.0 2144.5 2251.3 0.0 2251.3 ET (m3/ha) Tot. 2288.8 2080.5 2091.6 2153.7 5 ds/m SW (m3/ha) 1397.9 1189.5 1200.6 1262.7 FW (m3/ha) 891.0 891.0 891.0 891.0 FW (m3/ha) 891.0 891.0 891.0 891.0 SW% 0.6 0.6 0.6 0.6 FW (m3/ha) 891.0 891.0 891.0 891.0 FW (m3/ha) 891.0 891.0 891.0 891.0 Tot. 2414.3 2793.5 2483.9 2563.9 5 ds/m SW (m3/ha) 1523.3 1902.5 1592.9 1672.9 FW (m3/ha) 891.0 891.0 891.0 891.0 SW% 0.6 0.7 0.6 0.7 FW (m3/ha) 891.0 891.0 891.0 891.0 Trial A - 100% irrigation Irrigation salinity level 5 ds/m SW (m3/ha) Tot. SW% 2809.2 3700.2 0.8 3250.8 4141.8 0.8 3153.8 4044.8 0.8 3071.3 3962.3 0.8 10 ds/m SW (m3/ha) 1326.2 1119.4 1048 1164.5 10 ds/m SW (m3/ha) 1497.6 1692 1472.9 1554.2 10 ds/m SW (m3/ha) 2596.2 3143.1 2840 2859.7 Table 3. Water volumes m3/ha and saline water as percentages of total water applied during the cropping period Tot. 2217.2 2010.4 1939.0 2055.5 Tot. 2388.6 2583.0 2363.9 2445.2 Tot. 3487.2 4034.1 3731.0 3750.7 SW% 0.6 0.6 0.5 0.6 SW% 0.6 0.7 0.6 0.6 SW% 0.7 0.8 0.8 0.8 Under the A-Trial, the 100% irrigation with fresh water showed volumes of water 6% and 11% greater than the ones under the 5 ds/m and the 10 ds/m salinity levels respectively. Here, we would like to keep in mind that under saline irrigation treatments of the ECi 5 and 10 ds/m in both A and B trials, the volume of applied water is not totally saline water, as a portion of it was practiced with fresh water during the germination and the seedling establishment to assure high germination percentage and healthy seedlings. The volume of fresh water with respect to the total volume applied varied with the variation of the irrigation regime and accounted to 20, 30 and 40% of the total volume under 100, 60 and 40% irrigation treatments respectively. Regarding the deficit irrigation treatments, the data shows clearly that for the fresh water and irrigation with only 60% of the crop evapotranspiration demands resulted in nearly 36% water saving, whereas, under the 40% irrigation treatment, actually around 46% was the saving in the applied water. In this regard, the data also declares that the irrigation with the saline water instead of the fresh one, starting from the end of the seedling stage till the full maturity, we can have enormous saving in the fresh water amounting to nearly 80% under the 100% irrigation treatment. The deficit irrigation and the irrigation with saline water is a win win game: such approach, besides reducing the volume of water applied by 40 and 60% of that under 100% irrigation, which has its beneficial effect in reducing the accumulated salts in the active root zone, and consequently diminishing the leaching requirements. Furthermore, as it substitutes the fresh water for irrigation, it provides from 60% up to 70% saving in fresh water. Such data evidently indicates that through deficit irrigation and irrigation with saline water, there is a high potentiality of fresh water saving in the irrigated agriculture. However, the crucial question: what is the impact of both approaches on the cereals production and particularly the wheat? The answer to this question can be provided by analyzing the status of the grains yield of the investigated varieties under both approaches previously mentioned either individually and/or in combination (Fig.2) and (Table 4). Water Saving & Losses in the Yield 60 fw 5 ds/m% 50 10 ds/m% 40 Water saving Lost Yield 30 (% ) 20 10 0 60% 40% water saving 60% 40% lost yield Irrigation Regime Fig. 2. Water saving and the losses in the yield related to deficit irrigation 50 51 V1 V2 V3 Avg. V1 V2 V3 Avg. V1 V2 V3 Avg 0.0 0.0 0.0 0.0 SW (m3/ha) 0.0 0.0 0.0 0.0 SW (m3/ha) 2451.9 2157.5 2144.5 2251.3 FW (m3/ha) FW 0.0 0.0 0.0 0.0 SW (m3/ha) Trial B - 40% irrigation 2593.2 2868.2 2587.0 2682.8 FW (m3/ha) FW Trial B - 60% irrigation 3991.0 4344.8 4247.9 4194.6 FW (m3/ha) FW Irrigation salinity level Trial A - 100% irrigation ET (m3/ha) 2451.9 2157.5 2144.5 2251.3 Tot. 2593.2 2868.2 2587.0 2682.8 Tot. 3991.0 4344.8 4247.9 4194.6 Tot. 3.6 2.9 3.3 3.3 Yield (ton/ha) Yield (ton/ha) 4.3 3.7 4.2 4.1 5.4 5.5 6.3 5.7 Yield (ton/ha) 891 891 891 891.0 FW (m3/ha) 5ds/m FW (m3/ha) 891 891 891 891.0 5ds/m 891 891 891 891.0 FW (m3/ha) 5ds/m 1397.8 1189.5 1200.6 1262.7 SW (m3/ha) 1523.3 1902.5 1592.9 1672.9 SW (m3/ha) 2809.2 3250.8 3153.8 3071.3 SW (m3/ha) 2288.8 2080.5 2091.6 2153.7 Tot. 2414.3 2793.5 2483.9 2563.9 Tot. 3700.2 4141.8 4044.8 3962.3 Tot. 3.7 3.2 3.7 3.6 Yield (ton/ha) Yield (ton/ha) 4.3 4.0 4.5 4.2 5.1 5.7 6.3 5.7 Yield (ton/ha) Table 4. Water volumes m3/ha and grain yield ton/ha under investigated irrigation treatments 891 891 891 891.0 FW (m3/ha) 10ds/m 891 891 891 891.0 FW (m3/ha) 10ds/m 891 891 891 891.0 FW (m3/ha) 10ds/m 1326.2 1119.4 1048.0 1164.5 SW (m3/ha) 1497.6 1692.0 1472.9 1554.2 SW (m3/ha) 2596.2 3143.1 2840.0 2859.7 SW (m3/ha) 2217.2 2010.4 1939.0 2055.5 Tot. 2388.6 2583.0 2363.9 2445.2 Tot. 3487.2 4034.1 3731.0 3750.7 Tot. 3.6 3.2 3.7 3.5 Yield (ton/ha) Yield (ton/ha) 4.4 4.2 5.0 4.5 4.9 5.5 5.7 5.4 Yield (ton/ha) The presented data indicate that there is a high potentiality of using saline water for irrigation, even with relatively high salinity level up to 10 ds/m substituting the fresh water. Under the 100% irrigation treatment, the use of saline water leads to around 80% saving in the fresh water besides the advantage of having a yield production even with the relatively high salinity level (10 ds/m) of an average 5.4 tons/ha which is more or less equal to the one obtained under the fresh water irrigation treatment with only differences 0.3 ton/ha between both irrigation with fresh water and the 100% saline one. However, the disadvantage could be related to the increase in the accumulated salts in the active root zone exceeding the salinity level which the wheat could tolerate, and thereby leaching should be practiced with fresh water to avoid the deterioration in the soil productivity. However, under such situation, leaching is normally carried using nearly 15% leaching fraction, which indeed represents a small portion of fresh water already saved (Van Hoorn et al., 1993; Katerji et al., 2005). To avoid such raise up in salinity level in the active root zone, as a promising solution is to stop irrigation with saline water, and to irrigate and leach with fresh water particularly at the sensitive growth stages (flowering and seed filling). As shown in Table 4, the use of the 5 ds/m saline water besides saving 80% of the fresh water showed a grain yield identical to the one where fresh water was practiced. However, we shall be still faced with a relatively raise up in the salinity level in the active root zone, but with relatively lower values not exceeding the 5 ds/m and such accumulated salts to be leached will require small fresh water volumes. To use saline water successfully for cereals production, the case of wheat, and to avoid losses in the yield production, it is of paramount importance having a high germination percentage and a well developed healthy seedlings. Equally the salinity of the irrigation water should be decided in view of the salt tolerance degree of the growing crop and particularly the sensitive growth stages, and therefore the selection of the crop variety should be carefully considered (Hamdy, 1990a,b; Hamdy et al.,1993 and Hamdy, 1994). ). What we want to add here is that sustainable use of saline water for irrigation implies not only avoiding losses in the yield production but, equally, keeping the soil at high productivity without any deterioration, and that is the reason behind having a good quality water source, the fresh water, beside the saline one to be used at the sensitive growth stages and to satisfy the leaching requirements (Hamdy, 1996). Returning again to analysis (Table 4), the data concerning the yield production under deficit irrigation treatments using fresh water, the presented data indicates that the 60% irrigation treatment provided 36% fresh water saving besides giving a yield corresponding to 72% of that obtained under the 100% irrigation with an average 28% yield losses. Following the same trend under the sever deficit irrigation the 40% irrigation treatment, the saving 3 in the fresh water amounted to 1943 m /ha which is nearly 50% the volume applied under the 100% irrigation treatment, but, in the mean time the losses in the grain yield were substantially high, nearly 42% of that under full irrigation treatment. Such data indicates clearly that under deficit irrigation, the lower is the volume of applied water, the greater will be the fresh water saving, and the higher will be the losses in the yield production. Now to decide which irrigation regime we have to follow, we have to put on balance the fresh water saving on the right side, and the yield production on the other side. Indeed, to take the decision is not any easy one, as it is fundamentally depending on the availability of the fresh water resources, and the surrounding water problems, the prevailing socio economic conditions, the water allocation policies, as well as the food security achievements. All those factors, either separately, or combined together, play an important role on the decision to be taken which will greatly vary from one country to the other in view of the existing conditions. 52 Some countries will favor deficit irrigation practices, but only at 60% irrigation level accepting the 30% losses in grain production, and having around 40% saving in the fresh water to be allocated to other sectorial water uses suffering water shortages, and or to increase the irrigated area. Other countries, those characterized with acute shortages in available water resources could accept higher water saving and greater losses in the grain yield provided by the severe deficit irrigation, the 40% treatment and to use such saved water in other sectors of a relatively high return than the agriculture, like industry and tourism, and by satisfying the needs of wheat through foreign markets. Other countries, which have major interest in not only saving more water from the agricultural sector, but, in the mean time to have a high level of cereals production. Such countries can implement the deficit irrigation approach but through irrigation with 80% volumes of water which is the intermediate level between the 100% and the 60% irrigation regimes. Returning again to Table 3, where deficit irrigation was practiced using saline water of different salinity levels, the presented data concerning the water saving indicates that through such approach nearly 40% and 50% of the fresh water are saved under the 60% and 40% irrigation treatments respectively. On the other hand, concerning the grain yield production under the 60% irrigation treatments showed values of an average equal or slightly higher than that where 100% irrigation was practiced. However, under this deficit irrigation level, the yield was subjected to some losses of an average nearly 20% lower than that obtained under the 100% irrigation regime. Taking into consideration the salinity level of the irrigation water, it could be seen clearly that: for both ECi-values of 5 ds/m and 10 ds/m, no significant differences occurred, neither in fresh water saving percentages, nor in the grain yield production. Accordingly, the 60% deficit irrigation with the 5 ds/m salinity level is the one to be recommended, as it has several advantages as compared with the other irrigation treatments in providing a high water saving percentage in the fresh water, a convenient yield production corresponding to 80% of that under full irrigation, beside, having an active root zone with a lower ECi-value than that expected under the 100% irrigation treatment as well as the one with the high salinity level, the 10 ds/m. Regarding the 40% irrigation regime with saline water (Table 3), the data shows that under both investigated salinity levels, the 5 and the 10 ds/m, the fresh water saving as well as the yield production were more or less having the same values. However, under deficit irrigation treatment, the 40% in spite of its advantage in providing more water saving than the 60% treatment, yet, the grain yield was subjected to further losses nearly with values 20% lower with respect to the 60% irrigation treatment. The other point which should be carefully considered is the degree of salt accumulation in the active root zone and which will require under the 40% irrigation more fresh water for leaching as it is expected. That salts will be accumulated in excess in the active root zone with respect to the 60% irrigation treatment, particularly when irrigation is practiced with a higher ECI-values exceeding the 5 ds/m. Such data again gives the evidence that among the investigated irrigation treatments the 60% irrigation with saline water of an ECi-value 5 ds/m is the one to be recommended as it satisfies our major objective in achieving a good fresh water saving, convenient wheat production, and keeping the soil at high productivity through appropriate leaching management using a relatively low leaching fraction. Average EC-values (ds/m) in the active root zoon (0-45cm) at the critical growth stages At the critical growth stages, water samples representing the soil solution in circulation were sucked after each irrigation from the different soil layers by the aid of a vacuum pump, through the porous cups inserted at the depths 7.5, 22.5 and 37.5 cm. (Fig. 1). Average EC values in the different soil layers for the A trials under the two salinity levels (5 and 10ds/m) for the investigated varieties are given in Table 5. 53 Table 5. Salt accumulation and its distribution under 100% successive irrigation practices during the cropping period of the investigated wheat varieties EC ds/m Salinity level FW No. of irrigation Wheat growing stage Soil layer depth 0-15 15-30 30-45 avg. 1st Germination & seedling 0.87 0.85 0.87 0.86 2nd Early vegetative growth 0.87 0.88 1.00 0.92 3rd Full vegetative growth 0.84 0.74 0.73 0.77 4th Flowering 1.20 0.93 0.93 1.02 5th Seed filling & maturity 1.12 0.95 0.94 1.00 EC ds/m Salinity level 5ds/m No. of irrigation Wheat growing stage Soil layer depth 0-15 15-30 30-45 avg. 1st Germination & seedling 0.87 0.85 0.87 0.86 2nd Early vegetative growth 1.54 1.47 1.10 1.37 3rd Full vegetative growth 5.55 4.76 3.49 4.60 4th Flowering 7.57 7.57 7.81 7.65 5th Seed filling & maturity 8.82 8.12 8.85 8.59 EC ds/m Salinity level 10ds/m 54 No. of irrigation Wheat growing stage Soil layer depth 0-15 15-30 30-45 avg. 1st Germination & seedling 0.87 0.85 0.87 0.86 2nd Early vegetative growth 3.20 2.37 1.17 2.24 3rd Full vegetative growth 10.81 9.70 6.63 9.05 4th Flowering 13.73 13.41 14.14 13.76 5th Seed filling & maturity 16.21 15.85 17.80 16.62 It is worthy to repeat again that both the germination and seedling establishment stages were developed using only fresh water for irrigation. The end of the seedling stage i.e. the early vegetative growth 36 days from sowing started the irrigation with the saline water of 5 and 10 ds/m. Regarding the 100% fresh water irrigation treatment, it could be observed that for the investigated varieties successive irrigation with fresh water did not result in any increase in the salinity level of the whole soil profile as well as in the salt distribution within the different soil layers. Under the 100% irrigation with saline water of an ECi equals to 5 ds/m (Table 5.), the represented data indicates that there is a gradual increments in the accumulated salts in the different soil layers with increasing the number of irrigations. In the early vegetative growth, the EC for the whole soil profile under the investigated wheat varieties showed an average value around 1.36 ds/m which is very near to the one where irrigation was practiced with fresh water. However, at the end of the vegetative growth and the start of the flowering stage where the leaf area reached its maximum value there was a notable increase in the EC, being with an average value 4.15 ds/m, nearly three times greater than the one measured after the previous irrigation. It is well recognized that for the cereal crops, in our case the wheat, both flowering and seed filling stages are very sensitive ones to salinity. Regarding the data obtained, it could be concluded that irrigation with saline water up to 5 ds/m could be used safely, hence, the successive irrigation with such salinity level up to the flowering stage, the most sensitive one, the accumulated salts were of an average value around 4 ds/m which is at a level still below the one which the investigated wheat varieties could tolerate. Concerning the soil salinity management, in view of soil salinity data obtained, the leaching of accumulated salts frequently with each irrigation is not recommended. Leaching should be practiced at the end of the cropping period after harvesting, hence, as shown in (Table 5.), at the wheat ripening period, the accumulated salts were of an average value around 7.63 ds/m which is exceeding the threshold value which the investigated wheat varieties could tolerate. Doubling the irrigation salinity level up to 10 ds/m another picture appeared (Table 5.). As a general trend the salts were accumulated at the different soil depths as well as within the whole soil profile with values more or less the double of the ones recorded under the 5 ds/m irrigation treatment. In our study, irrigation with 10 ds/m saline water, the flowering stage, accumulated salts were of an EC-value around 9 ds/m which is relatively a high value exceeding the one that wheat could tolerate. The presence of accumulated salts with relatively high EC–value at this sensitive stage requires immediate leaching of the accumulated salts to avoid the negative salinity impact on the next sensitive growth stage i.e. the seed filling stage. Such data indicate that the degree of accumulated salts in the active root zone will differ according to the variation in the salinity level of irrigation water. In this regard, monitoring and following up the soil EC–values during the cropping period particularly at the critical growth stages is of paramount importance to decide on when to leach and what should be the leaching fraction. Soil salinity after wheat harvesting After harvesting, the soil samples packed in the lysimeter were divided into the following soil layer depths: (0-15 cm) the upper layer, (15-30 cm) the intermediate layer and (30-45 cm) the bottom layer. EC of the above mentioned investigated layers was determined using the saturation paste technique (Table 6). 55 Table 6. Electrical conductivity (ds/m) of the different soil layers measured in the soil saturation paste after harvest Electrical conductivity (ds/m) of different soil layers Wheat varieties Treatment V1 V2 Soil layer (ds/m) Trial A (100% irr. treatment) 0 - 15 0.94 1.02 15 - 30 0.80 0.80 FW 30 - 45 0.90 0.71 Avg. 0.88 0.84 0 - 15 6.59 6.36 15 - 30 3.59 4.95 5 ds/m 30 - 45 3.81 4.47 Avg. 4.66 5.26 0 - 15 9.95 11.09 15 - 30 6.48 9.00 10 ds/m 30 - 45 7.17 9.55 Avg. 7.86 9.88 Trial B (60% irr. treatment) 0 - 15 1.15 1.04 15 - 30 0.90 0.74 FW 30 - 45 0.92 0.81 Avg. 0.99 0.86 0 - 15 5.58 5.34 15 - 30 3.58 4.53 5 ds/m 30 - 45 3.60 4.24 Avg. 4.25 4.70 0 - 15 7.97 10.41 15 - 30 6.34 9.61 10 ds/m 30 - 45 6.90 7.69 Avg. 7.07 9.24 Trial B (40% irr. treatment) 0 - 15 1.19 0.80 15 - 30 0.77 0.78 FW 30 - 45 0.90 0.80 Avg. 0.95 0.79 0 - 15 3.86 3.37 15 - 30 3.10 3.58 5 ds/m 30 - 45 3.39 3.44 Avg. 3.45 3.46 0 - 15 8.89 8.37 15 - 30 6.68 7.01 10 ds/m 30 - 45 6.36 7.86 Avg. 7.31 7.74 V3 Avg. 0.94 0.75 0.80 0.83 5.51 4.66 4.66 4.94 7.74 7.28 8.31 7.78 0.97 0.79 0.80 0.85 6.15 4.40 4.31 4.95 9.59 7.59 8.34 8.51 1.09 0.71 0.89 0.89 4.54 3.21 3.07 3.60 10.16 6.30 6.37 7.61 1.09 0.78 0.87 0.92 5.15 3.77 3.63 4.19 9.51 7.42 6.98 7.97 0.85 0.79 0.81 0.82 2.98 2.87 2.91 2.92 7.45 7.31 7.60 7.45 0.95 0.78 0.84 0.85 3.40 3.18 3.25 3.28 8.24 7.00 7.27 7.50 As shown in Table 6, keeping the salt concentration level of the irrigation water constant and changing the wheat varieties, the degree of salt accumulation in the different soil layers as well as the average salt concentration level within the whole soil profile were more or less of similar values, with only slight difference between the investigated varieties. On the other hand, considering the degree of salt accumulation within the whole soil profile as well as in the different soil layers, the data shows that there was a gradual increase in the salinity concentration with the gradual increments of the ECi values. Considering the average electrical conductivity values within the whole soil profile, it is noticed that under the 100% successive irrigation with saline water of 5 ds/m from seedling stage till maturity brought the accumulated salts in the whole soil profile to an average Ec-value of 4.95 ds/m. Doubling the Eci from 5 to 10 ds/m resulted in a 72% increase in the accumulated salts with an average value of 8.51 ds/m. 56 Under trial A, considering the active root zone where the wheat roots penetrate is of depth lying between 30 and 45 cm it can be observed that under successive irrigation with the low salinity level 5 ds/m, the accumulated salts in the active root zone up to 45 cm reached after harvesting an average Ec-value around 5 ds/m which the crop wheat with its investigated varieties could tolerate (Hamdy,1999). This clearly explains the reason behind having a grain yield production under the 5 ds/m irrigation treatment more or less equal to the one obtained under irrigation with fresh water. This again confirm, that for the investigated wheat varieties, irrigation with saline water up to 5 ds/m can be used safely without having any significant losses in the grain yield. In this regard and concerning saline irrigation management, it could be wisely said that it is not necessary to leach the accumulated salts at the previous sensitive growth stage (flowering and seed filling), hence, the accumulated salts at both stages will be of an Ec-value substantially lower than the ones at the harvest time and therefore, it is recommended that leaching be carried out at the end of the cropping period after the yield harvest. This is not the case, where irrigation was practiced with water of salinity level 10 ds/m. The accumulated salts in the active root zone (0-45 cm) were of an average value 8.5 ds/m which is relatively higher than the one that wheat sensitive growth stages can tolerate. To avoid the negative impact of salts being accumulated in excess in the active root zone on the grain production, it is advisable that leaching to be carried out before reaching such relatively high soil salinity levels particularly at the sensitive growth stages. Concerning the salt distribution and accumulation in the different soil layers, the presented data (Table 6.)indicates that for the investigated Eci-values including the fresh water, there is a general trend characterizing the salt accumulation with the different soil depths, showing the higher Eci-value at the upper layer (0-15 cm), followed by the bottom one (30-45 cm), while the intermediate layer (15-30 cm) was the lowest in its accumulated salts. The intermediate soil layer being with an Ecivalue lower than in the ones of both upper and bottom layer could be explained on the ground that the intermediate layer is subjected to two processes both leading to the removal of salts from this layer: The first, during the irrigation and the downward water movement leaching salts from this layer to the bottom one, the second, during the drying and the upward movement of water by capillary rise carrying with it the salts to upper surface layer. Regarding the Trial-b (Table 6), where deficit irrigation was practiced, the presented data indicates that under both investigated Eci, the accumulated salts as well as its distribution in the different soil layers followed a trend identical to the one under the A-Trial. However, as presented in Fig. 3. The distribution of salts in the soil layers FW 9 5 ds/m 8 10 ds/m ECi (ds/m) 7 6 5 4 3 2 1 0 100% 60% 40% Irrigation treatments Fig. 3. The distribution of salts in the different soil layers at the end of the cropping period 57 Under deficit irrigation (Trial-B), the accumulated salts with the whole soil profile as well as in the different soil layers, were of lower values than the ones measured under the 100% irrigation treatments. Under the 60% irrigation treatment with the 5 ds/m saline water, the soil profile was of an Eci-value 4.19 ds/m with nearly 15% reduction in the accumulated salts observed under the 100% irrigation treatment. This was also the case with the relatively high salinity level 10 ds/m, where the accumulated salts were of values nearly 10 % lower than the ones corresponding to the 100% irrigation treatment. Under sever water stress, the 40% irrigation treatment, the accumulated salts were found with an average values lower than the ones related to the 60% irrigation treatment and corresponded to 66% and 88% of the Eci-values obtained under the 100% irrigation for the 5 and 10 ds/m irrigation salinity level respectively. CONCLUSIONS In view of the presented data and results obtained, we can come up to some important conclusions, among them the following to be highlighted: Irrigation with saline water up to 5 ds/m could be used safely, hence, the successive irrigation with such salinity level up to the flowering stage, the most sensitive one, the accumulated salts were of an average value around 4 ds/m which is at a level still below the threshold value which the investigated wheat varieties could tolerate. For wheat varieties under investigation, irrigation salinity level could be raised up to 10ds/m resulting in only around 10% losses in the grain yield production. The presented data show that the higher is the salinity level of irrigation water; the lower will be the consumptive water use, and the greater will be the biomass and the grain water use efficiencies. This also holds true under deficit irrigation using saline water. The smaller is the volume of water applied and the higher is its salinity level; the better will be the improvement in both biomass and grain water use efficiencies. Among the investigated irrigation treatments the 60% irrigation with saline water of an ECivalue 5 ds/m is the one to be recommended as it satisfies our major objective in achieving a good fresh water saving, convenient wheat production, as well as keeping the soil at a relatively low salinity level could be easily leached by precipitation and or by relatively small fresh water volumes and thereby bringing the soil again to its original productivity level. REFERENCES Bernstein, L. and François, L.E. (1973). Comparison of drip, furrow and sprinkler irrigation, Soil Sci 115:73-86. François, L.F. (1981). Alfalfa management under saline condition with zero leaching. Agronomy Journal, 73-1042.1946. Hamdy, A. (1990a). Management practices under saline water irrigation. Symp. On Scheduling of irrigation for vegetable crops under field condition. Acta Horticulture, vol. 2, N° 278. Hamdy, A. (1990b). Crop management under saline irrigation practices. In: Water, soil and crop management relating to the use of saline water. A. Kandiah (ed.) FAO,AGL/MISC/16/90, 108-116. Hamdy, A. (1990c). Saline irrigation practices: leaching management. Proceedings of The Water and Wastewater. Conference, 24-27 April, 1990. Barcelona, Spain. Hamdy, A. and Nassar, A. (1991). Saline irrigation practices and management: modes of water application and leaching (in press). Hamdy A. and Lacirignola, C. (1993). An overview of water resources in the Mediterranean countries. Cahiers Options Méditerranéennes, Vol. I, n°1: Water resources development and management in Mediterranean countries. Pp. 1.1-1.32. Hamdy, A., Abdel-Dayem, S. and Abu-Zeid, M. (1993). Saline water management for optimum crop production. Agricultural water management 24:189-203. Hamdy, A. (1994). Use and management of saline water for irrigation towards sustainable development. In: Sustainability of irrigated agriculture. (eds) Pereira L. 58 Hamdy, A. (1996). Saline irrigation: assessment and management techniques. In: Choukr-Allah, R.; Malcom, L.V.; Hamdy A. (eds). Halophytes and Biosaline Agriculture. Dekker, New York, pp. 147-181. Hamdy, A. (1999). Saline irrigation assessment and management for a sustainable use. Proceedings: special session on: Non-conventional resources management and practices.UWRM Sub-network. Annual meeting. IAV Hassan II, Rabat, Morocco, 28 October, 1999. pp. 3-69. Hamdy, A. and Katerji, N. (2006). Water crisis in the Arab World. Analysis and Solutions. CIHEAM/MAIB publication, pp. 60. Van Hoorn, J.W.; Katerji, N.; Hamdy, A. and Mastrorilli, M. (1993). Effect of saline water on soil salinity and on water stress, growth and yield of wheat and potatoes. Agr. Water Management 23, 247-255. Katerji, N.; Van Hoorn, J.W.; Hamdy, A.; Mastrorilli, M.; Nachit, M.M. and Oweis, T. (2005). Salt tolerance analysis of chick-pea, fababean and drum wheat varieties. II Durum Wheal. Agric. Water Management 72, 192-207. 59 IRRIGATION STRATEGIES FOR OPTIMAL USE OF SALINE WATER IN MEDITERRANEAN AGRICULTURE G. Crescimanno and P. Garofalo Università di Palermo, Dipartimento ITAF – Sezione Idraulica, Viale delle Scienze, 13 90128 Palermo, ITALY. [email protected] SUMMARY – In this paper management strategies optimizing irrigation, and also reducing the risk of secondary salinization, were explored for seven Sicilian soil profiles by using the SWAP model. Two viable options addressing constraints of limited water availability were simulated for the seven soil profiles. These options were (i) different irrigation scheduling, i.e. irrigation with a fixed amount of water but different number of irrigations, and (ii) cyclic strategies, i.e. alternating two irrigation waters having different salinity. Analysis of three different irrigation scheduling evidenced that making a limited number of irrigations (two in our case), using larger application volumes, determined a lower risk of salinization. With reference to the role of cracks in the process of salt-leaching, the simulations performed indicated that water stored in cracks promoted leaching of the accumulated solutes, and that neglecting the presence of cracks led to overestimating salinization. Cyclic strategy proved to be the best management option to be suggested to reduce the risk of salinization. Findings concerning the role of cracks in the process of salt-leaching suggested that, under field conditions, application of a leaching solution was more efficient if the soil presented a considerable degree of cracking. Key words: Salinization, Cracking, Irrigation, Management scenarios RESUME – Dans ce papier on a exploré des différentes options de gestion de l'irrigation qui peuvent aider à réduire le risque de salinisation en appliquant le model SWAP à sept profiles de sol en Sicile. On a exploré (i) trois différentes calendrier d'irrigation et (ii) l'alternance de deux eaux d'irrigation ayant une différente salinité. Les résultants ont démontré que la meilleure gestion se peut réaliser en faisant deux irrigations seulement. En plus, les résultas ont démontré l'importance que les fissures du sol peuvent avoir dans la lixiviation des sals accumulés dans le sol, en indiquant qu'il faut tenir en compte les fissures dans la prévision de la salinisation du sol. L'alternance de deux eaux de différente salinité se démontre être la pratique la plus efficace pour prévenir la salinisation du sol. En plus, l'application d'une solution lixiviante se démontre plus efficace si la même est fait quand le sol présente une considérable percentage de fissures. Mots-clés: Salinisation, Fissures, Irrigation, scénarios de gestion INTRODUCTION In Mediterranean regions, irrigation with saline/sodic waters, often a consequence of intensive agricultural systems, is one of the main causes of secondary salinization, resulting in soil degradation. Although accurate worldwide data are not available, vast areas of irrigated land are increasingly threatened by salinization and/or sodication. Sustainable land management practices are urgently needed to preserve the production potential of agricultural land while safeguarding environmental quality. According to one of the various definitions given by FAO (1993), sustainable land management combines “ technologies, policies and activities aimed at integrating socio-economic principles with environmental concern so as to protect the potential of natural resources and prevent degradation of soil and water quality”. In Sicily, the increasing scarcity of good quality waters coupled with intensive use of soil under semi-arid to arid climatic conditions results in irrigation with saline waters. Salinization is closely associated with the process of desertification, defined as “land degradation in arid, semi-arid and dry 61 sub-humid areas resulting from climatic variations and human activities”, with the term “land” including soil, water resources, crops and natural vegetation (UNEP, 1991). Without appropriate management, irrigated agriculture can be detrimental to the environment and endanger sustainability. Therefore, the goal of modern irrigation is to develop methods allowing to save water and to improve both the water and the salt distribution within the root zone, also preserving maintenance of good structural conditions. According to one of the various definitions given by FAO (1993), sustainable land management combines “technologies, policies and activities aimed at integrating socio-economic principles with environmental concern so as to protect the potential of natural resources and prevent degradation of soil and water quality”. van Dam et al. (1997) developed a model describing water and solute transport in the vadose zone, taking into account soil shrinkage and cracking. This model, named SWAP93, provides as output the water content (and matrix potential), as well as the concentration of the soil solution, C, from which the electrical conductivity of the saturated extract (ECsat) can be also calculated (Rhoades, 1996). Crescimanno and Garofalo (2005) tested the applicability of SWAP for prediction of water content (θ) and electrical conductivity of the saturated extract (ECsat) in a Sicilian clay soil having a high shrink-swell potential and susceptibility to cracking. Using θ measurements collected from seven profiles located in a Sicilian vineyard, they found that using the parameter estimation method based on multi-step outflow experiments, and representing the soil hydraulic properties by the Brutsaert retention equation, coupled with the hydraulic conductivity model proposed by Gardner (B-G model), it was possible to obtain an accurate prediction of θ. In this paper management strategies optimizing irrigation, and also reducing the risk of secondary salinization, will be explored for some Sicilian soil profiles by using the SWAP model. Options addressing constraints of limited water availability were simulated. These options were (i) different irrigation scheduling, i.e irrigation with a fixed amount of water but different number of irrigations, and (ii) cyclic strategies, i.e. alternating two irrigation waters having different salinity. MATERIALS AND METHODS Soil shrinkage and hydraulic characteristics Data collection was carried out in a 25 by 25 m field located in Sicily (37° 40’ 55” N; 12° 38’ 50” E) where irrigation with saline waters is performed on grapes by a sprinkler system, which allows high application rates at the soil surface. Irrigation water is taken from the Trinità artificial reservoir. The electrical conductivity of irrigation water, ECw, is about 2.1 dS/m. However, when rainfall is particularly low, and water stored in this reservoir is not enough to cover irrigation needs, water from wells is used for irrigation, with ECw values up to about 6.2 dS/m. Seven soil profiles (Baglio1-Baglio7) were considered in this field. The soil shrinkage curve was determined by measuring vertical and horizontal shrinkage on undisturbed soil cores (diameter d=8.5 cm, height H=11.5 cm) (Crescimanno and Provenzano, 1999). The shrinkage characteristic was expressed by the model proposed by Kim (Crescimanno and Garofalo, 2005).Bulk density (ρb) was determined from the shrinkage curve and used to calculate the volumetric water content, θ, which therefore accounted for a variable soil volume. The coefficient of linear extensibility, COLE (Grossman et al., 1968), indicating the shrink-swell potential (Parker et al., 1977), was also calculated. Parameter estimation was carried out according to Crescimanno and Garofalo (2005), representing the soil hydraulic functions by: 62 - the equation proposed by Brutsaert (B) (1966), for the water retention curve: [ θ − θr n' = Θ = 1 + α ′h θs − θr ] −1 (1) - coupled with the model proposed by Gardner (1958) (G) for the hydraulic conductivity function k(h): k (h ) = k sat 1 + βh (2) λ where h (cm) is the pressure head, θs is the volumetric water content at saturation, θr is the residual water content, k is the unsaturated hydraulic conductivity (cm/h), ksat is the saturated hydraulic conductivity (cm/h), α’, n’, β and λ are empirical parameters. The soil physical and chemical properties, together with the soil shrink-swell potential, were reported in Table 1. The soil hydraulic parameters were reported in Table 2. % ____ Shrinkswell potential § h=-333 cm to oven-dry ESP # Sand Silt _____ COLE ‡ ECsat ¶ cm Clay Depth Classification † Horizon Table 1. Classification, physical and chemical properties, COLE and shrink-swell potential of the considered soils. dS/m % Baglio1 Typic Chromoxerert Ap 0-30 35 28 37 0.052 Medium 2.38 3.5 Baglio1 Typic Chromoxerert A1 30-60 33 23 44 0.049 Medium 3.56 5.2 Baglio2 Typic Chromoxerert Ap 0-30 36 24 40 0.065 High 1.83 3.8 Baglio2 Typic Chromoxerert A1 30-60 30 24 46 0.069 High 2.52 5.0 Baglio3 Typic Chromoxerert Ap 0-30 34 27 39 0.103 Very high 1.75 3.8 Baglio3 Typic Chromoxerert A1 30-60 34 21 45 0.083 High 2.35 4.8 Baglio4 Typic Chromoxerert Ap 0-30 32 28 40 0.054 Medium 1.80 3.4 Baglio4 Typic Chromoxerert A1 30-60 33 23 44 0.062 High 2.47 5.1 Baglio 5 Typic Chromoxerert Ap 0-30 35 28 37 0.132 Very high 2.17 3.5 Baglio 5 Typic Chromoxerert A1 30-60 21 37 42 0.122 Very high 2.06 3.8 Baglio 6 Typic Chromoxerert Ap 0-30 42 29 29 0.113 Very high 1.93 3.4 Baglio 6 Typic Chromoxerert A1 30-60 44 23 33 0.101 Very high 2.59 3.5 Baglio 7 Typic Chromoxerert Ap 0-30 44 27 29 0.080 High 2.22 3.0 Baglio 7 Typic Chromoxerert A1 30-60 43 22 35 0.077 High 2.88 3.5 † Soil Survey Staff, 1992 ‡ COLE= coefficient of linear extensibility § Parker et al., 1977 ¶ ECsat = Electrical Conductivity of saturated soil extract # ESP = Exchangeable Sodium Percentage 63 Table 2. Hydraulic parameters determined according to the hydraulic conductivity equation proposed by Gardner coupled with the Brutsaert retention equation (B-G model). Hydraulic parameters Soil Baglio 1 Baglio 1 Baglio 2 Baglio 2 Baglio 3 Baglio 3 Baglio 4 Baglio 4 Baglio 5 Baglio 5 Baglio 6 Baglio 6 Baglio 7 Baglio 7 Horizon Ap A1 Ap A1 Ap A1 Ap A1 Ap A1 Ap A1 Ap A1 ksat † cm/h 4,70 0,30 1,49 0,05 4,05 0,29 2,67 0,11 0,78 0,03 0,24 0,01 1,74 0,02 θs ‡ 3 cm /cm 0,47 0,47 0,50 0,48 0,47 0,47 0,50 0,48 0,51 0,49 0,51 0,49 0,55 0,53 θr § 3 3 cm /cm 0,23 0,28 0,27 0,28 0,29 0,29 0,25 0,25 0,31 0,31 0,31 0,32 0,28 0,30 3 α' # -1 cm 0,002 0,017 0,038 0,025 0,024 0,009 0,040 0,032 0,0031 0,0081 0,0012 0,0118 0,0174 0,0730 n' # -1 cm 0,883 0,408 0,463 0,322 0,876 0,420 0,520 0,265 0,826 0,483 0,514 0,500 0,386 0,336 β# λ' # 0,079 1,486 2,049 0,333 0,470 2,659 0,068 1,174 0,130 0,313 2,89 1,13 1,03 0,134 2,917 1,650 2,270 3,081 4,065 2,704 4,209 1,321 3,275 1,626 1,295 1,045 1,98 2,48 † ksat = saturated hydraulic conductivity of the soil matrix, fixed at measured value ‡ θs = saturated volumetric water content at saturation, fixed at measured value § θr = residual water content # parameters of B-G model Management scenarios Climatic data (rain intensity, maximum and minimum temperature, rainfall height) recorded daily from 08/07/1998 to 31/12/2000 by a rain gauge located in the field were used as input in SWAP. Annual rainfall in 1998, 1999 and 2000 was 390 mm in average and the annual reference evapotranspiration in 1998, 1999 and 2000 was 1450 mm in average. Although an annual amount of irrigation water equal to 120 mm is supplied under normal conditions, due to the constraints of limited water availability, the annual irrigation amount supplied from 1998 to 2000 was very low, and equal to 66 mm in 1998, to 48 mm in 1999, and to 24 mm in 2000. The irrigation season in this vineyard usually ranges from mid June to mid September. A root distribution characterized by 60% roots in the 30-70 cm layer, and by 20% both in the 0-30 cm and in the 70-100 cm layers, was assumed (Crescimanno and Garofalo, 2005). Simulations were performed by using a bottom boundary condition of freely draining profile, and the B-G hydraulic parameters were used to simulate water transport. The following management scenarios were considered: 3 − Scenario 1 Irrigation scheduling. Irrigation with a fixed annual volume of 1120 m , and electrical -1 conductivity of irrigation water equal to 6.2 dS m (the most critical possible salinity value), but testing different options in terms of number of water applications, i.e.: 1a: eight water applications, which means weekly irrigation; 1b: four water applications, which means irrigation every two weeks; 1c: two water applications, which means a monthly water application. The 1c is the irrigation scheduling more often used in this irrigated area. To explore how cracks may affect the process of salt-accumulation and/or leaching, scenario 1c was repeated under the hypothesis of no shrinkage, which means no cracking and bypass flow. This scenario was indicated with 1c’. 3 − Scenario 2c – Cyclic strategy. Irrigation with a fixed annual volume of 1120 m , but alternating two waters of different salinity. The saline irrigation water is the one used in Scenario1, the less saline water, with ECw=2.1 dS m-1, which is the value measured during the winter season, is used when the crop is more sensitive to salinity according to the crop physiology. 64 A performance indicator (Smets et al., 1997) was used to evaluate the impact of management scenarios on salinization: ∆S = S f − S i (3) where Si and Sf (mg cm-2) represent the quantity of salts accumulated in the soil profile at the starting date and to the end of simulation, respectively. In order to compare the different scenarios in terms of crop transpiration, and of evaporation, the following ratios were calculated: RT=Tscen/T1c (4) RE=Escen/E1c (5) where Tscen (cm) and Escen (cm) were the actual crop transpiration and evaporation of the considered scenario, and T1c (cm) and E1c (cm) represent transpiration and evaporation obtained by scenario 1c, which is the commonly applied irrigation scheduling in the irrigated area. RESULTS AND DISCUSSION Irrigation scheduling (Scenario 1) Amount of salts accumulated in the soil profile, ∆ S, (mg/cm2) Decreasing ∆S values were obtained for the seven profiles passing from scenario 1a to scenarios 1b and 1c (Fig. 1). This result can be explained by the fact that reducing the number of irrigations, and increasing the amount of water applied, determined a higher application intensity (I). Since in all the three scenarios irrigation was performed in summer (starting date June 15), when cracks were open and the hydraulic conductivity (HC) of the soil matrix was low, bypass flow of water was prevalent. According to the SWAP, at increasing I, an increasing amount of water, and of dissolved salts, bypasses the upper layers, rapidly reaching the bottom layers. This is the reason why, when irrigation was performed according to scenario 1c, a higher percentage of water and salts bypassed the surface layers compared with scenarios 1b and 1c. 50 45 40 Scenario 1a Scenario 1b Scenario 1c 35 30 25 20 15 10 5 0 Baglio 1 Baglio 2 Baglio 3 Baglio 4 Baglio 5 Baglio 6 Baglio 7 Fig. 1. Amount of solutes accumulated, ∆S (g/cm2), in the seven soil profiles according to the three considered irrigation scheduling (Scenario 1) 65 Concerning relative transpiration, the highest RT values were associated with scenario 1c (Table 3). This was not only a consequence of the lower ∆S, but was also the consequence of water content distribution in the profile after irrigation (Fig. 2, Baglio1 profile). As can be seen in the figure, θ values higher than those obtained by the 1a and by the 1b scenarios were obtained by scenario 1c in the 5-60 cm layer, where the maximum percentage of roots was concentrated, one day after irrigation. This water distribution was the consequence of bypass flow, which promoted storage of water in the deepest layers. Consistently with this water distribution, the lowest evaporation was also obtained in scenario 1c, as demonstrated by the RE values (Table 4). 0,23 Volumetric w ater content, θ, (cm3/cm3) 0,28 0,33 0,38 0,43 0,48 0 -10 Depth (cm) -20 -30 -40 -50 -60 -70 Scenario1a) -80 Scenario1b) -90 Scenario1c) -100 Fig. 2. Water distribution along the soil profile one day after irrigation (Baglio1 profile) Table 3. Ratio (RT) between transpiration (T) obtained by scenarios 1a, 1b, 1c and 2c, and T obtained by scenario 1c. Baglio 1 0,88 0,98 1,00 1,06 Actual Transpiration (cm) 29,43 Baglio 2 0,75 0,90 1,00 1,04 44,51 Baglio 3 0,88 0,95 1,00 1,03 43,77 Baglio 4 0,87 0,98 1,00 1,02 43,62 Baglio 5 0,81 0,92 1,00 1,02 44,58 Baglio 6 0,81 0,89 1,00 1,02 28,85 Baglio 7 0,79 0,90 1,00 1,03 35,62 Scenario 1a 66 Scenario 1b Scenario 1c Scenario 2c Table 4. Ratio (RE) between evaporation (E) obtained by scenarios 1a, 1b, 1c and 2c, and E obtained by scenario 1c. Scenario 1a Scenario 1b Scenario 1c Scenario 2c Actual Evaporation (cm) Baglio 1 1,04 1,01 1,00 1,00 86,05 Baglio 2 1,19 1,08 1,00 0,99 57,55 Baglio 3 1,11 1,06 1,00 0,99 60,32 Baglio 4 1,08 1,05 1,00 0,99 65,23 Baglio 5 1,15 1,02 1,00 1,00 61,41 Baglio 6 1,07 1,04 1,00 0,99 84,07 Baglio 7 1,10 1,05 1,00 0,99 70,24 These results showed that under our conditions, reducing the number of irrigations, and increasing the irrigation amount at each application, proved to be the best strategy to prevent salinization, also enhancing crop transpiration. Cyclic strategies (Scenario 2c) With reference to alternating two waters of different salinity, expressed as ECw, (first water with lower salinity, then water with higher salinity) (Scenario 2c), the ∆S values obtained by Scenario 2c (Fig. 3) were significantly lower that those provided by Scenario 1c for all seven profiles. This indicated that, as expected, this strategy effectively prevented salinization (Rhoades, 1989; Crescimanno et al., 2002). Amount of salts accumulated in the soil profile, ∆S, (mg/cm2) 45 Scenario 1c 35 Scenario 2c 25 15 5 -5 Baglio 1 Baglio 2 Baglio 3 Baglio 4 Baglio 5 Baglio 6 Baglio 7 -15 Fig. 3. Amount of solutes accumulated in the soil profiles, ∆S (g/cm2), according to scenarios 1c and 2c. However, considerable differences were found between the different profiles in terms of ∆S (Fig. 3). Negative ∆S values, indicating salt-leaching, were obtained only for Baglio4 and Baglio2; negligible ∆S values, indicating no solute accumulation, for Baglio1; and positive and increasingly higher ∆S, indicating salt-accumulation, for Baglio7, Baglio3, Baglio5 and Baglio6 (in order of increasing ∆S). 67 Baglio7 Baglio6 Baglio5 Baglio4 Baglio3 Baglio2 Baglio1 Solute flux through bottom profile, CWQ, (g/cm2/d) The negative ∆S values found for Baglio4 and Baglio2 were certainly due to the highest CWQs (Fig. 4); the difference (diff2=∆S1c - ∆S2c) between the ∆S values obtained with scenarios 1c and 2c decreased from 30.40 mg cm-2 (Baglio4) to 26.90 mg cm-2 (Baglio 6), following the same order in which CWQ decreased. 0 -10 -20 -30 -40 -50 -60 -70 CWQcr -80 CWQm -90 -100 Fig. 4. Overall flux of solutes, CWQ (g/cm2), from the soil profiles in the 2c scenario 2,5 2,0 1,5 1,0 Scenario 1c 0,5 Scenario 2c Dec-00 Oct-00 Aug-00 Jun-00 Apr-00 Feb-00 Dec-99 Oct-99 Sep-99 Jul-99 May-99 Mar-99 Jan-99 Nov-98 Sep-98 0,0 Jul-98 Average ECsat in the soil profile (dS/m) 3,0 Fig. 5. Average electrical conductivity of the saturated extract, ECsat (dS/m), vs time (Baglio1 profile). Higher RT values corresponded to scenario 2c compared with those obtained by scenario 1c (Table 3). This result can be explained by the lower average values of ECsat in the soil profile (Fig. 5), which . determined a higher root water flux, Sa. The same RE values (Table 4) were found in scenarios 1c and 2c. The reasons for this are that RE was not influenced by salinity, and that scenarios 1c and 2c determined the same water distribution along the profile. 68 Cracking, salinization and salt-leaching (Scenario 1c’) To evaluate the influence of cracks on salinization, and to check the consequences of neglecting shrinkage and cracking on selection of irrigation strategies preventing salinization, scenario 1a was repeated with the assumption of no shrinkage and cracking, i.e. rigid soil (scenario 1c’). Amount of salts accumulated in the soil profile, ∆ S, (mg/cm2) The ∆S values obtained by scenario 1c’ (Fig. 6) were always higher than those obtained by scenario 1c, in which cracks were taken into account. Since the only difference between scenarios 1c and 1c’ was that in this latter scenario the soil was considered as non shrinking, with no cracks, the lower ∆S obtained by scenario 1c certainly depended on the fact that the cumulative water flow from the cracks into the matrix, CWF (cm) (Fig. 7), was taken into account. Significantly different CWFs were found for the different profiles, with the lowest value for Baglio3, and increasingly higher values for Baglio1, Baglio6, Baglio5; Baglio2 and Baglio7 (in the order of increasing CWF). A significantly higher CWF was found for Baglio4. It is interesting to notice that cracks differently affected the difference in ∆S between scenarios 1c and 1c’. For Baglio1 and Baglio3 this difference (diff1=∆S1c∆S1c’) was negligible; for the other profiles, the effect of the cracks was more pronounced, especially for Baglio2 (diff1= 8.0 mg cm-2), Baglio7 (diff1 = 8.2 mg cm-2) and Baglio4 (diff1=16.6 mg cm-2). The increasing order of diff1 corresponded to a decreasing order of CWF (Fig. 7). 50 Scenario 1c 40 Scenario 1c' 30 20 10 0 Baglio 1 Baglio 2 Baglio 3 Baglio 4 Baglio 5 Baglio 6 Baglio 7 Fig. 6. Amount of solutes accumulated in the soil profiles, ∆S (g/cm2), in scenarios 1c and 1c’ Comparing results of scenarios 1c and 1c’ on the different soil profiles suggested that if cracks and water storage in cracks were not taken into account, the risk of salinization was overestimated. The magnitude of this overestimation depended on the soil shrinkage behaviour, being greater at increasing shrinkage and cracking. For soils showing a considerable susceptibility to shrinkage and cracking, management strategies optimizing irrigation should therefore be obtained by physicallybased models taking into account a variable soil volume. 69 9 8 7 6 5 4 3 2 1 Baglio7 Baglio6 Baglio5 Baglio4 Baglio3 Baglio2 0 Baglio1 Cumulative water flow form cracks into matrix, CWF, (cm) 10 Fig. 7. Cumulative water flow from the cracks into the matrix, CWF (cm), obtained for the different profiles CONCLUSIONS Analysis of three different irrigation scheduling evidenced that the best scheduling was to make a limited number of irrigations (two in our case), using larger application volumes. This result was found to depend on the water distribution in the soil profile, which in turn depended on bypass flow of water, determined by the higher water application intensity involved in this scenario. As a consequence in our case, bypass flow was a mechanism determining a favorable water distribution. However, this result can be considered valid only for crops developing a deep root distribution. The best irrigation scheduling is therefore a function of soil type and crop characteristics, and the best option is to be found by simulations taking specific site conditions into account. Cyclic strategy proved to be the best management option to be suggested to reduce the risk of salinization (scenario 2c).With reference to the role of cracks in the process of salt-leaching (Scenario 1c’), the simulations performed indicated that water stored in cracks promoted leaching of the accumulated solutes, and that neglecting the presence of cracks led to overestimating salinization. This overestimation was significant for the soils having a considerable susceptibility to shrinkage and cracking. When irrigation is performed in cracking soils, simulation models taking into account cracks should therefore used to explore sustainable irrigation strategies. Acknowledgments Research supported by MURST (Rome, Italy), PRIN 2005:“Strategie e problematiche legate alla desalinizzazione di terreni argillosi con crepacciature”. REFERENCES Bouma, J. (1991). Influence of soil macro porosity on environmental quality. Advances in Agronomy, 46: 1-37. Bronswijk, J.J.B. (1988). 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Proc., 3: 31-42. 71 EFFECT OF SUPPLEMENTARY SALINE IRRIGATION ON YIELD AND STOMATAL CONDUCTANCE OF WHEAT UNDER THE MEDITERRANEAN CLIMATIC CONDITIONS * ** A. Yazar , A. Hamdy , B. Gencel *, M. S. Sezen *** and M. Koç **** * Irrigation and Agricultural Structures Department, Cukurova University, 01330 Adana-Turkey; ** Mediterranean Agronomic Institute, via Ceglie 9, 70010 Valenzano, Bari, Italy *** Soil and Water Research Institute, Water Management Research Unit, P.O.Box 23 33400 Tarsus, Turkey **** Field Crops Department, Cukurova University, 01330 Adana-Turkey SUMMARY- The response of wheat (Triticum aestivum L.) to different salinity levels of irrigation water under the Mediterranean climatic conditions was investigated in a field study at the experimental station of Cukurova University in Adana, Turkey during the 2001-2002 growing season. Saline waters with electrical conductivity values of 0.5 (canal water), 3.0, 6.0, 9.0, and 12.0 dS/m were used for irrigation of wheat. The average grain yields ranged from 5940 to 6484 kg /ha in different treatments. The effect of salinity levels of irrigation water used in the study on grain yields was not significantly 2 different (P<0.4057). Average dry-matter yields varied from 1506 to 1691 g/m from the different treatments at harvest time. However, treatments resulted in similar biomass yields (P<0.3664). Water 3 use efficiency (WUE) values from the treatments ranged from 1.29 to 1.44 kg/m . As the salinity level of irrigation water increased WUE values also increased slightly. Harvest index (HI) values from the different treatments varied from 0.38 to 0.42. However, there was no significant difference among the treatments. Generally soil salinity increased with salinity content of irrigation water used in the study. Soil salinity decreased almost linearly with increasing depth in the profile. There was no well-defined relationship between stomatal conductances of wheat leaves and irrigation water salinities under the study conditions. Thus, the results obtained provide a promising option for the use of poor quality water can be used for irrigation of wheat crop in the Mediterranean region without undue yield reduction and soil degradation since effective winter rainfalls leach the salts out of the root zone as long as an efficient drainage system is provided. Key words: Saline water, wheat yield, dry matter yield, water management, water use efficiency, stomatal conductance RESUME- La réponse et la conductance stomatale du blé (Triticum aestivum L.) aux différents niveaux de salinité de l’aux d’irrigation dans les conditions climatiques méditerranéennes a fait l’onjet d’une étude menée à la expérimentale de l’Université de Cukurova à Adana, Turquie pendant la saison 2001-2002. Des eaux salées ayant des valeurs de conductivité électrique de 0.5 (eau douce), 3.0, 6.0, 9.0, et 12.0 dS/m ont été utilisée pour l’irrigation de blé. Les rendements moyens en graines variaient de 5940 à 6484 kg/ha dans les différents traitements. L’analyse de la variance des données des rendements en graines a montré que l’effet des niveaux de salinité de l’eau d’irrigation utilisée dans l’étude sue les rendements en graines n’était pas significantivement différent.Les rendements moyens en matiére séeche variaient de 1154 à 1394 g/m2 dans les différents traitements à l’époque de la récolte. Toutefois, les traitements montraient presque les mêmes valuers des rendements en biomasse. Puisque le blé n’a été irrigué que deux fois pendant le cycle cultural et vu les pluies assez importantes reçues pendant le cycle, les sels apporté au sol avec l’eau d’irrigation sont restés à des niveaux acceptables et n’ont pas affecté le rendement en biomasses du blé. En général, la salinité du sol a augmenté avec la teneur en sel de l’eau d’irrigation utilisée dans l’étude. Donc, l’eau d’irrigation salée peut être utilisée pour l’irrigation de la culture de blé dans le région méditerranéennes du fait des pluies efficaces hivernales qui lessivent les sels de la zone racinaire, tant que l’on prévoit un système de drainage efficace. Mots clés: blé, salinité, l’eau salée, conductance stomatale 73 INTRODUCTION Supplies of good quality irrigation water are expected to decrease in the future because the development of new water supplies will not keep pace with the increasing water needs of industries and municipalities. Thus, irrigated agriculture faces the challange of using less water, in may cases of poorer quality, to provide food and fiber for an expanding population. Some of the these future water needs can be met by using available water supplies more efficiently, bu in may cases it will prove necessary to make increased use municipal waste waters and irrigation drainage waters. Limited supplies of fresh water are increasingly in demand for competing uses and create the need to use marginal quality water in agriculture. From the viewpoint of irrigation, the use of marginal quality waters require careful planning, more complex management practices and stringent monitoring procedures, than when good quality water is used (Oster, 1994; Beltran, 1999; Hamdy, 2002). When the availability of freshwater is limited, agriculture is likely to be forced to make increasing use of nonconventional waters, either brackish water or sewage effluents (Hamdy, 1999; Dinar et al., 1986). Saline water is a potential source for irrigation. Recent research developments on plant breeding and selection, soil crop and water management, irrigation and drainage technologies enhanced and facilitated the use of saline water for irrigating crops with minimum adverse effects on the soil productivity and environment (Shalhavet, 1994; Rhoades et al, 1992; Pereira, 1994). There is usually no single way to achieve safe use of saline water in irrigation. Many different approaches and practices can be combined into satisfactory saline water irrigation systems; the appropriate combination depends upon economic, climatic, social, as well as edaphic and hydrogeologic situations (Rhoades et al., 1992; Rhoades, 1999; Oster and Grattan, 2002; Bradford and Letey, 1993). Salinity of irrigated agricultural soils can be managed satisfactorily for salt-tolerant and moderately salt tolerant crops when using saline water for irrigation (Ayers and Westcot, 1985; Hamdy, 2002). Irrigation with saline water usually causes a progressive soil salinization, which is more or less severe according to salt supply, soil properties (whether clay or sandy), leaching caused by rainfall and applied irrigation technique. As the soil salinity rises, the osmotic potential soil water decreases resulting in reduced water availability and physiological diseases (Shannon et al., 1994). A careful selection of the crop and the variety most suited to a given environment is of paramount importance for obtaining high efficient production. In general, crops can tolerate salinity up to threshold level above which, the yields decrease approximately linearly as salt concentrations increase (Maas, 1986; Letey et al, 1985). Wheat (Triticum aestivum) is one of the most important cereal crops of the world to nourish the mankind. It is grown in wide range of climatic zone and mostly in irrigated conditions. In the arid and semi-arid areas, saline ground water is a common feature. Irrigation with saline water throughout the growth period of crops resulted in deterimental effect on growth and yield potential of the crops. Therefore, it will be of vital interest for scientist to try to overcome the salinity menace to predict the wheat crop growth development and yield potential with varying salinity of irrigation water on the basis of long term experimentation (Chauhan and Singh, 1993). Chauhan and Singh (1993) conducted a seven-year consecutive saline irrigation experiment in India and conclude that in light textured soils and semi arid climatic conditions, wheat can be grown upto ECiw-8 dS/m comparable to control (canal water). The saline irrigation at ECiw-12 and 16 dS/m reduced wheat yield by 21 and 37 per cent over control with negative significant correlation (r = -0.42). The reduction in yield mainly caused by poor germination and tillering, stunted growth and to some extent by low 1000 grain weight. Datta et al. (1998) carried out an experiment in Karnal (India) using five levels of saline irrigation treatments (ECiw = 0.5, 6, 9, 12, 18 and 27 dS/m) along with recommended agronomic and cultural practices. Optimum yield was obtained from the treatment irrigated with canal water as 5.9 t/ha, followed by 6 dS/m as 5.69 t/ha, and 9 dS/m as 5.39 t/ha. The treatment irrigated with saline water of 12 dS/m resulted in yield of 5 t/ha; 18 dS/m gave 4.51 t/ha. As the salinity level of irrigation water increased yield level decreased accordingly. 74 A research aimed at investigating the possibility of applying supplemental irrigation to wheat and barley during their sensitive phenophases of flowering and seed formation using brackish water with salinity levels generally considered too high for its use (EC of 3–9 dS/m) was conducted in a greenhouse at the Mediterranean Agronomic Institute in Bari, Italy. Results showed the possibility of securing high yields, with mean reductions of only 21% in barley and 25% in wheat compared to the fully, fresh-water irrigated control, through the application of limited amounts of brackish water. The sustainability of the practice is presumably high, due to the limited amounts of added salts, which can be easily leached out even by a modest precipitation (Hamdy et al., 2005). In the Mediterranean climate, rainfed cereal crops are planted in autumn and harvested in late spring, relying on the rains during this period for the conclusion of their cycle; the vagaries of rains, however, often put at risk the final harvest. Thus, supplemantal irrigation of wheat is widely practiced in the region to avoid water shortages. Reuse of drainage water for crop production is a common practice in downstream section of the Lower Seyhan Irrigation Project (LSP) area in the Mediterranean region of Turkey. Therefore, effective salinity control measures must be implemented for sustainable irrigated agriculture, which requires safe use of saline, low quality irrigation and drainage waters for crop production. Reuse of agricultural drainage water is either being practiced to save fresh water for other uses or as in the case of LSP, insufficient fresh water availability for the downstream users due to over use of canal water in the upstream section. Thus, farmers in the downstream section have no other choice but to use drainage water for irrigating their crops (Tekinel et al., 1989). Yazar and Yarpuzlu (1997) conducted a five-year study in the Lower Seyhan Irrigation Scheme in Turkey from 1991 to 1995 in order to evaluate the response of cotton and wheat grown in rotation on a clay soil to drainage water applications with four different leaching fractions (varying from 0.15 to 0.60) as well as salinity build-up in the soil profile. Effect of winter rainfall on salt balance of the soil profile was also investigated in this study. The results revealed that using drainage water with salinities varying from 1.26 to 6.26 dS/m for irrigation of wheat did not result in the salinity built up in the soil profile in the Lower Seyhan Project in Turkey. The main objectives of this study are to evaluate the yield production and yield loss in relation to the various salt concentration levels of irrigation water; to investigate the salinity build up in the soil profile under different irrigation programs; to determine the water use efficiency (WUE) under saline water conditions, which is a key parameter in water saving program. In addition, to study the effect of saline supplementary irrigation on leaf stomatal conductance of wheat in the esatern Mediterranean region of Turkey. MATERIALS AND METHODS Experimental site The field experiment was conducted at the Research Station of the Irrigation and Agricultural Structures Department of the Cukurova University in Adana, Turkey during 2001/2002 wheat growing season (November-June, 2002). Descriptions of some physical and chemical characteristics of the experimental soil are given in Tables 1 and 2, respectively. As shown in Table 1, the soil of the experimental site is classified as Mutlu soil series (Palexerollic Chromoxeret) with clay texture throughout the soil profile. Available water holding capacity of the soil is 256.2 mm in the 120 cm soil profile. Table 2 indicates that soil salinity at planting time is well below the salinity threshold level for reducing wheat yields of ECe=6.0 dS/m. Wheat is classified as medium tolerant to soil salinity (Maas, 1986). 75 Table 1. Description of the some physical characteristics of the experimental soil Soil Depth cm Particle Size Distribution (%) Soil Texture Field Capacity 3 3 (cm /cm ) Bulk Density 3 (g/cm ) Wilting Saturation Point 3 3 (cm /cm ) (cm3/cm3) Sand Silt Clay 0-5 28 21 51 C 42 23.8 51 1.19 5-15 28 21 51 C 42 23.8 51 1.19 15-30 28 21 51 C 42 23.8 51 1.19 30-60 28 19 53 C 45 23.2 54 1.16 60-90 28 18 54 C 44 21.8 55 1.15 90-120 27 19 54 C 42 18.8 50 1.25 Table 2. Description of the some chemical properties of the experimental soil Cations (me/l) Depth (cm) ECe (dS/m) pH CaCO3 (%) O.M.* (%) 0-10 0.335 6.95 5.92 10-20 0.310 6.63 20-40 0.353 40-60 ++ ++ + Anions (me/l) + - -2 - Ca Mg Na K HCO3 SO4 Cl 1.28 1.48 1.10 0.40 0.10 2.06 0.10 0.92 5.92 1.28 1.66 1.10 0.32 0.08 2.14 0.26 0.77 6.81 6.11 1.14 1.94 1.17 0.35 0.07 2.24 0.40 0.89 0.354 6.93 6.38 0.98 1.48 0.80 0.43 0.05 1.84 0.10 0.83 60-80 0.314 7.15 6.65 - 1.45 1.31 0.44 0.05 2.04 0.34 0.88 80-100 0.324 6.99 7.40 - 1.52 1.09 0.56 0.05 2.14 0.21 0.87 100-120 0.295 6.95 7.45 1.16 0.97 0.57 0.05 1.90 0.12 0.74 *OM:Organic matter Treatments and experimental desing Balatilla, a bread variety of wheat (Triticum aestivum L.) was planted on 24 November 2001 at a row spacing of 12.5 cm, and after plant establishment dikes were constructed around each plot since border irrigation was used due to close growing nature of wheat crop. Wheat grain yield was 2 determined by harvesting all plants in an area of 8 m in each plot. Fertilizer applications were based on soil analysis recommendations. All treatment plots received the same amount of total fertilizer. A compound fertilizer of 20-20-0 was applied at arate of 75 kg N and 75 kg P2O5 as pure matter per ha at planting. The rest of N fertilizer was applied on February 23, 2002 in the form of ammonium nitrate (26% N) during tillering at a rate of 75 kg N per ha. The saline water was prepared by mixing fresh water (0.5 dS/m) with sea water (54 dS/m) in order to obtain an average salinity level of 12 dS/m in a concerete pool with dimensions of 10m x 10 m x 2.5 m at the experimental site. Five salinity levels of irrigation water with ECiw of 3.0, 6.0, 9.0, and 12.0 dS/m (being various dilutions of stock solution in the pool with irrigation canal water) along with canal water (control) with salinity of 0.5 dS/m were tried in a completely randomised block design with three replications. In addition, a treatment was included in the study by applying a 10% leaching fraction to 12.0 dS/m treatments after flowering. Thus, a total of 6 treatments were studied. Namely, 0.5, 3.0, 6.0, 9.0, and 12.0 dS/m; and 12.0+10% leaching after flowering stage were condidered. Each experimental plot was 5 m long and 2.5 m wide. 76 Irrigation, soil water and salinity monitoring Gated pipes were used for applying water to plots. For mixing saline water and fresh water at specified salinity level, tanks were utilized at the head of each plot. Flow meters were utilized to determine the volume of water applied to each plot. The amount of water applied to each treatment plot was based on replenishing the soil water deficit within the 100 cm soil profile during the irrigation interval of 14 days to field capacity (Sezen and Yazar, 1996). Soil water in each experimental plot was measured with a neutron probe (CP Model 503DR Hydroprobe) as well as by gravimetric sampling at 0.20 m depth increments down to 1.00 m, every two-week and prior to each irrigation application. A calibration equation developed for the experimental site was used to calculate the soil water in the profile prior to irrigation. At planting, and at flowering stage all treatment plots were soil sampled at depth intervals of 0-10 cm, 10-20 cm, 20-40 cm, 40-60, 60-80, 80-100 cm using an auger. The electrical conductivity of the soil samples was measured on saturation extracts (ECe) with an EC meter. Water use (ET) of the wheat crop was calculated through the use of water balance equation: ET = I + P ± ∆S − D (1) where ET is evapotranspiration (mm), I irrigation (mm), P precipitation (mm), D deep percolation (i.e., drainage, mm), ∆S is change of soil water storage in a given time period (mm), ∆t (days) within the plant rooting zone. The amount of water above the field capacity is considered as deep percolation in this study. 3 2 Water use efficiency (kg/m ) was computed as the ratio of grain yield (kg/m ) to water use (m). Irrigation water use efficiency was determined as the ratio of grain yield for a particular treatment to the applied water for that treatment. Harvest index (HI) was obtained as the ratio of grain yield (kg/m2) 2 to aboveground biomass yield (kg/m ). Dry-matter, leaf area The phenological growth stages were observed weekly throughout the study. For this purpose, plants in 1.0 m long row section in each replicate for each treatment were randomly selected representing all the characteristics of its treatment. Occurrences of different growth stages were monitored on these plants. Plant height measurements were also carried out. The development of the above-ground portion of the crop was monitored by destructive sampling during the season. Plant samples consisted of all plants within 0.5 m of a row were taken at two-week intervals. Leaf area of the samples was measured with an optical leaf area meter. 2 Wheat plants were hand harvested in all treatment plots by cutting all plants in 8 m section of each plot on June 6, 2002. Then, using a tresher grains were separated from the strarw, and grain yields were determined. Stomatal conductance measurements Stomatal conductance measurements were carried out on five main treatments during the vegetative growth stage before and after irrigation. Diffusion porometry is based on measurement of the rate of water vapor loss from a leaf or portion of a leaf enclosed in a porometer chamber and the resistance is measured. Stomatal conductance is calculated as the inverse of the resistance measured (Beadle et al., 1986). The measurement is done with an automatic porometer (Li-Cor, Lincoln, NE, USA, Model Li-1600), that diffuses water vapor. From each treatment fully developed upper two leaves were taken for measurement. Measurements were carried out during noon time. The obtained values were calculated twice to reflect abaxial and adaxial leaf surfaces. MSTATC program (Michigan State University) was used to carry out statistical analysis. Treatment means were compared using Duncan’s Multiple Range Test (Steel and Torrie, 1980). 77 RESULTS AND DISCUSSION Rainfall and irrigation A total of 742 mm of rainfall received during the 2001-2002 wheat growing season was significantly higher than the long-term average annual rainfall of 630 mm. Table 3 summarizes the average monthly climate data compared to the long-term mean climatic data for the Lower Seyhan Plain, where the experiment was carried out. Except the rainfall, other climatic prameters during the growing season were typical those prevail in the Mediterranean region. Because of the above normal rainfall in December 2001 during the wheat growing season in the experimental area, wheat was irrigated twice. The first irrigation application was made on March 22, 2002 and 100 mm of water was applied to treatments with different salinity levels. Treatment of 12.0 dS/m+ 10% leaching fraction (LF) received 110 mm. The second irrigation was applied on May 7, 2002 and 80 mm of irrigation water with different salinity contents were applied to the treatment plots. Treatment of 12.0 dS/m+ 10% LF received 88 mm of irrigation water. Thus, a total of 180 mm of irrigation water with different salinity levels were applied to treatments except treatment 12dS/m+10% LF, which received 198 mm of irrigation water. Dry matter and grain yields The data pertaining to effect of varying saline irrigation on wheat crop growth and grain yields, dry matter yields, water use, water use efficiency, harvest index and 1000-grain weight values obtained from treatments irrigated with water with different salinity levels are presented in Table 4. As indicated in Table 4, the average grain yields ranged from 5940 to 6484 kg /ha in the different treatments. Table 3. Historical monthly mean and growing season climatic data of the experimental area Climatic Parameters Nov. Dec. Jan. Feb. Long-term average (1929-2000) 15.1 11.1 9.9 10.4 Average Temperature (°C) Rainfall (mm) 67.2 118.1 111.7 92.8 Relative Humidity (%) 63 66 66 66 Wind Speed (m/s) 1.6 1.9 2.2 2.2 47.0 47.3 56.1 Evaporation, Class A Pan (mm) 66.3 2001-2002 Growing Season 13.9 10.7 7.9 12.3 Average Temperature (°C) Rainfall (mm) 88.1 320.9 109.2 68.1 Relative Humidity (%) 67.4 78.2 66.1 64.7 Wind Speed (m/s) 1.6 1.8 2.1 2.3 36.1 58.9 64.0 Evaporation, Class A Pan (mm) 73.4 -2 -1 273.3 166.9 289.8 359.1 Solar Radiation (MJ m d ) March April May June 13.1 67.9 66 2.3 84.9 15.2 21.4 28.0 25.4 25.6 4.8 69 67 66 1.6 1.9 2.5 11 8.6 19 5.6 320.5 14.7 40.3 67.4 2.3 88.9 465.1 16.5 88.8 76.0 1.7 72.5 511.8 21.4 22.0 68.4 2.0 155.2 657.7 26.6 0.8 62.9 2.4 215.5 706.5 Variance analysis of the grain yield data showed that the effect of salinity levels of irrigation water used in the study on grain yields was not significantly different (Table 4). Therefore, treatments resulted in similar wheat grain yields in this experiment. This result is expected because wheat was irrigated twice during the growing season due to significant amount of rainfall received in the study area. Bernstein (1964), Bhumbla et al, (1964), Kanwar and Kanwar (1969) and Tripathi and Pal (1980) have reported the reduction in yield of wheat with high saline irrigations. Besides, grain yield, crop growth and yield attributes are found to vary with sensitivity for salinity. Chauhan and Singh (1993) reported a remarkable reduction in grain yield started above ECiw 8 dS/m in India. With ECiw 12 and 16 dS/m the grain yield lowered by 21 and 37% respectively. Reduction in grain yield per unit EC of water from 8 to 16 dS/m was about 4%. 78 Table 4. Grain and dry matter yield, water use and water use efficiency (WUE) data for the treatments Salinity of Irrigation Water (dS/m) 0.5 (FW) 3.0 6.0 9.0 12.0 12.0+(10%) Dry Matter Yield (kg/ha) 15063 15230 16210 16341 15216 16915 Grain Yield (kg/ha) Harvest Index (HI) 6176 5940 6484 6373 6391 6427 0.41 0.39 0.40 0.39 0.42 0.38 Seasonal Irrigation (mm) Water Use (mm) 180 180 180 180 180 198 480 461 496 462 452 445 WUE 3 (kg/m ) 1.286 1.288 1.307 1.379 1.414 1.444 1000 Grain Weight (g) 45.2 46.1 46.4 45.1 46.2 46.8 Average dry-matter yields varied from 1506 to 1691 g/m2 from the different treatments at harvest time. However, six different saline irrigation treatments resulted in similar biomass yields. Since wheat was irrigated only twice during the growing season, and significant amount of rainfall received during the wheat growing period, salts added to soil with irrigation remained at insignificant level and did not affect the biomass yield of wheat. Chauhan and Singh, (1993) reposted that drymatter yield declined only at ECiw12 and 16 dS/m by 18 and 33% respectively, as compared to canal water. Seasonal water use of wheat in the different treatments ranged from 445 to 496 mm. The amount of rainfall greater than soil water deficit in the soil profile was considered as deep percolation. Thus, considerable amount of deep percolation occurred in this particular year, and leached out significant amount of salts from the profile. Water use efficiency (WUE) values from the treatments ranged from 1.29 to 1.44 kg/m3. As the salinity level of irrigation water increased WUE values also increased slightly. However, the WUE values were not significantly different among the treatments studied. Zwart and Bastiaansen (2004) viewed the water use efficiency values for major crops and reported the range of WUE for wheat, 3 varying between 0.6–1.7 kg/m throughout the world. Dry-matter yields obtained from the different treatments varied from 15063 kg/ha in treatment irrigated with fresh water (0.5 dS/m), to 16915 kg/ha in treatment of 12.0 + (10%) dS/m. However, there was no significant difference in the dry-matter yield among the treatments. The evolution of leaf arae index (LAI) under different treatments with time is presented in Fig. 1. As shown in Figure 1, irrigation water salinity resulted in gradual reduction of LAI. The negative impacts of salinity on the LAI development started to appear after the flowering stage. The reduction in LAI ranged from 10.8 to 12.0% lower than the fresh water treatment. However, the differences in LAI values were not significant among the treatments. LAI 7 0.5 dS/m 6 3.0 dS/m 5 6.0 dS/m 4 12.0 dS/m 3 12+(10%) dS/m 9.0 dS/m 2 1 0 Jan 1 Feb. 26 March 20 Apr 16 mag 02 Date of Observation Fig. 1. Evolution of leaf area index (LAI) in different treatments 79 Harvest index (HI), defined as the ratio of grain yield to dry matter yield, values from the different treatments are given in Table 4. It shows that the harvest index values from the different treatments varied from 0.38 to 0.42. However, there was no significant difference among the treatments. Average 1000-grain weight values from the different salinity treatments ranged between 45.1 and 46.8 g. However, 1000-grain weight values obtained from the treatments were not significantly different. However, Chauhan and Singh (1993) stated that 1000 grain weight was started to decline from ECiw 2 dS/m onwards progressively but with very low degree. Soil salinity Soil salinity profiles resulting from the different salinity treatments are shown in Fig. 2. Soil salinity profiles were established at planting, at flowering, and at harvest for each treatment studied. As shown in the Fig. 2, soil salinity at planting varied from 0.27 dS/m in surface soil layers to 0.50 dS/m in deeper layers. However, soil salinity throughout the profile was very low in the experimental soil. Soil salinity increased slightly in the surface layer (ECe=0.35 dS/m) in the treatment irrigated with fresh water. Generally soil salinity increased with salinity content of irrigation water used in the study. Highest soil salinity was observed in the 0-10 cm soil layer in treatments irrigated with ECw of 12 dS/m and 12 dS/m+10% leaching as ECe=4.3 dS/m. Then soil salinity decreased almost linearly with increasing depth in the profile. Soil salinity in the 100-120 cm soil layer was 0.8 dS/m in these two most saline treatment plots. There was no significant difference in soil salinities between these two treatments. Soil salinity during the wheat growing period did not reach the threshold salinity level of 6.0 dS/m (Ayers and Westcot, 1985). EC, dS/m 0,0 1,0 2,0 3,0 4,0 5,0 0 Soil Depth, m 20 40 Planting Flow ering 60 0.5 dS/m 3 dS/m 80 6 dS/m 9 dS/m 100 12 dS/m 12+(10%) dS/m 120 Fig. 2. Soil salinity profiles at planting, flowering and harvest for the treatments The treatment irrigated with saline irrigation water of 9.0 dS/m resulted in soil salinity of 3.2 dS/m in the top layer (0-10 cm) and 2.2 dS/m in the 10-20 cm layer. Then soil salinity decreased with increasing depth. The lowest salinity in the soil profile was observed in the 100-120 cm soil layer with 0.6 dS/m. Soil salinity prior to the flowering growth stage was very similar in all treatments and were lower than 0.5 dS/m throughout the profile as indicated in Fig. 2. The treatment irrigated with saline irrigation water of 6.0 dS/m resulted in soil salinity of 2.1 dS/m in the top layer (0-10 cm) and 1.4 dS/m in the 10-20 cm layer. Then soil salinity decreased with increasing depth. The lowest salinity in the soil profile was observed in the 100-120 cm soil layer with 0.5 dS/m. The treatment irrigated with saline irrigation water of 3.0 dS/m resulted in soil salinity of 1.65 dS/m in the top layer (0-10 cm) and 1.1 dS/m in the 10-20 cm layer. Then soil salinity decreased with increasing depth. The lowest salinity in the soil profile was observed in the 100-120 cm soil layer with 0.4 dS/m. 80 Rainfalls received during the growing season especially prior to flowering stage leached out the salts from the profile in all treatments studied. Irrigation application after the flowering stage resulted in increased soil salinities in saline irrigation water treatments since the rainfall received after flowering stage was not sufficient to leach out salts from the profile. From the research findings, it can be conclude that saline irrigation water can be used for irrigation of wheat crop in the Mediterranean region since effective winter rainfalls leach the salts out of the root zone as long as an efficient drainage system is provided. Average pH values of the saturation extracts under different treatments at harvest remained between 7.0 and 8.0 in all plots. There were no significant difference among the treatments with respect to pH values of the saturation extracts. Thus, pH was not affected considerably by the saline irrigation water applications. Highest average sodium absoprtion ratio (SAR) value was determined in the top layer of soil as 9.74 in the treatment irrigated with water of 9.0 dS/m, followed by 12.0 dS/m treatment as 7.53 and 7.11 in the treatment irrigated with 12 dS/m +10% leaching. In general, SAR values increased with increasing salinity of irrigation water. However, SAR values observed in all treatments did not constitute a serious threat to wheat growth under the study conditions. Stomatal conductance, gs Stomata play a pivotal role in controling the balance between the water loss and carbon gain i.e. biomass production. Measurements of the size of the stomatal opening or of the resistance to CO2 and water vapor (H2O) transfer between the atmosphere and the internal tissue of the leaf imposed by the stomata are important in studies of biomass production. This is particularly the case in cropping situations where it is important to maximize water use efficiency (Beadle et al., 1986). Average stomatal conductances of wheat leaves measured in different dates under the different treatments are given in Figure 4. As indicated in Figure 4, stomatal conductance measurements were started on April 8 and continued until May 17, 2002. Stomatal conductance (upper+lower epidermis) values on April 8, was highest in 3.0 dS/m treatment followed by 12 dS/m+10% leaching treatment. -2 The lowest average stomatal conductance was observed in treatment of 9.0 dS/m as 382 mmol m s 1 . A total of 5 mm of rainfall recieved prior to measurements on the same day. On April 12, stomatal conductances were very similar in all treatments except in 12 dS/m+10% leaching, in which highest 2 value was measured as 839 mmol/m s. Stomatal conductance values decreased in all treatments on April 15. The highest stomatal conductance was measured in the treatment irrigated with fresh water, and the lowest was observed in treatment of 12.0 dS/m. On May 3, a total of 2 mm of rainfall was received before the measurements, stomatal conductances reached their highest values in most treatments except in the treatment of 3.0 dS/m. Highest stomatal conductance was measured in treatment irrigated with fresh water followed by 12dS/m+10% LF, and 12 dS/m treatments. On May 7, 80 mm of irrigation water of different salinity content was applied to treatment plots. Average stomatal conductance values slightly decreased on May 10 as compared to May 3 values. A total of 2 mm of rainfall was received on May 16. On May 17, slightly decreased on low salinity treatments, and slightly increased on higher salinity treatments. Zang et al. (1998) evaluated the diurnal variation of stomatal conductance in China with 600 mm annual rainfall, and stated that midday depression of gs were also evident in field grown wheat. Xue et al. (2004) explained the gs movement of field grown wheat in the United States as a feedforward response, which means that stomata sensed the air vapor pressure directly. Increased water loss through the stomata caused a water potential decline of the guard cell. In conclusion, there was no well-defined relationship between stomatal conductances and irrigation water salinities under the study conditions. 81 Stomatal Conductance (mmol m-2 s-1) 1200 1000 800 0,5 3 600 6 400 9 12 200 0 4-Apr 12+%10 9-Apr 14-Apr 19-Apr 24-Apr 29-Apr 4-May 9-May 14-May 19-May Date Fig. 3. Variation of average stomatal conductance values of wheat leaves under the different treatments CONCLUSIONS In the Mediterranean climate, rainfed cereal crops are planted in autumn and harvested in late spring, relying on the rains during this period for the conclusion of their cycle; the vagaries of rains, however, often put at risk the final harvest. The response of wheat (Triticum aestivum L.) to different salinity levels of irrigation water under the Mediterranean climatic conditions was investigated in a field study at the experimental station of Cukurova University in Adana, Turkey during the 2001-2002 growing season. Saline waters with electrical conductivity values of 0.5 (fresh water), 3.0, 6.0, 9.0, and 12.0 dS/m were used for irrigation of wheat. The research results revealed that the effects of salinity levels of irrigation water used in the study on grain yields as well as dry-matter yields were not significantly different. Since wheat was irrigated only twice during the growing season, and significant amount of rainfall received during the wheat growing period, salts added to soil with irrigation remained at a level that did not affect the biomass yield of wheat. Generally soil salinity increased with salinity content of irrigation water used in the study. Highest soil salinity was observed in the 0-10 cm soil layer in treatments irrigated with ECw of 12 dS/m and 12 dS/m+10% leaching as ECe=4.3 dS/m. Then soil salinity decreased almost linearly with increasing depth in the profile. 3 Water use efficiency (WUE) values from the treatments ranged from 1.29 to 1.44 kg/m . As the salinity level of irrigation water increased WUE values also increased slightly. However, the WUE values were not significantly different among the treatments studied. There was no well-defined relationship between stomatal conductances of wheat leaves and irrigation water salinities under the study conditions. Thus, saline irrigation water under the semi arid climatic conditions in the Mediterranean region can be used for irrigation of wheat crop up to ECw-12 dS/m comparable to control (canal water) because of effective winter rainfalls leach the salts out of the root zone as long as an efficient drainage system is provided. The sustainability of this practice is presumably high, due to the limited amounts of added salts, which can be easily leached out even by a modest precipitation. 82 REFERENCES Ayers, R.S., and Westcott, D.W. (1985). Water Quality for Agriculture. FAO Irrigation and Drainage Paper 29 Rev.1., Rome. Beadle, C.L., Ludlow, M.M., and Honeysett, J.L. (1986). 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Hamdy, A. (1996). Use of unconventional water resources as a fresh water saving practice. In Proc. th of 16 Congress on Irrigation and Drainage, ICID and CHIEAM-IAM-B. Cairo, Egypt. Hamdy, A., (1999). Saline irrigation assessment and management for sustainable use. In: Proceedings on Non-Conventional Water Resources Practices and Management and Annual Meeting UWRM Sub-Network Partners IAV Hassan II, Rabat, Morocco, 28 October 1999. Hamdy, A. (2002). A review paper on: Soil salinity, crop salt response and crop salt tolerance mechanisms. In Proceedings of Advances in Soil Salinity and Drainage Management to Save Water and Protect the Environment. October 15-27, 2002, Alger, Algeria. P. 3-72. Hamdy, A., Sardo V. and, Farrag Ghanem K.A., (2005). Saline water in supplemental irrigation of wheat and barley under rainfed agriculture. Agricultural Water Management (in pres). Kanwar, J.S., and B.S. Kanwar, (1969). Quality of irrigation waters. Trans. 9 Inter. Cong. Soil Sci. J., pp: 391-403. Khosla, B.K. and Gupta, R.K. (1997). Response of wheat to saline irrigation and drainage. Agric. Water Management 32(3):285-291. Maas E.E. (1986). Salt tolerance of plants. Applied Agricultural Research 1(1):12-26. Oster, J.D.(1994). Irrigation with poor quality water. Agricultural Water Management 25(3):293-297. Oster, J.D., Grattan, S.R. (2002). Drainage water reuse. Irrig. Drain. Syst. 16, 297–310. Pereira, L.S., (1994). Research needs for sustainable use of low quality water in agriculture. In: Proceedings of the VIII IWRA World Congress on Water Resources, Cairo, Egypt, 21–25 November 1994. Rhoades, J.D., (1999). Use of saline drainage water for irrigation. In: Skaggs, R.W., van Schilfgaarde, J. (Eds.), Agricultural Drainage. American Society of Agronomy (ASA)-Crop Science Society of America (CSSA)-Soil Science Society of America (SSSA), Madison, Wisconsin, USA, pp. 615– 657. Rhoades J.D., Kandiah, A., and Mashali, A.M. (1992). The use of saline water for crop production. FAO Irrigation and Drainage Paper No:48, Rome. Sato, T., Abdalla, O.S., Oweis, T.Y., Sakuratani, T., (2006). Effect of supplemental irrigation on leaf stomatal conductance of field grown wheat in Northern Syria. Agr. Water Management ??? Sezen, S.M. and Yazar, A. (1996). Determining wheat yied-water relations under Mediterranean climatic conditions. Turkish Journal of Agriculture and Forestry. 20:41-48. Shannon, M.C., Grieve, G.M., and François, L.E. (1994). Whole-plant response to salinity. In: PlantEnvironment Interactions (R.E. Wilkinson, ed.) New York: Marcel Dekker, Inc., p199-244. Steel, R.G.D., Torrie, J.H, 1980. Principles and Procedures of Statistics, Second ed. McGraw-Hill, New York. Tekinel, O., A. Yazar, B. Cevik, R. Kanber. (1989). Ex-post evaluation of the Lower Seyhan Project in Turkey. In Irrigation: Theory and Practice. Edited by J.R. Rydzewski and C.F. Ward. Pentec Press, London. Tripathi, B.R. and B. Pal, (1980). The quality of irrigation water and its effect on soil characteristics and on the performance of wheat, Paper No.8.2, International Symposium on Salt affected soils, held in Karnal, India. 83 Xue, Q., Weiss, A., Arkebauer, T. J., Baenziger, P.S., (2004). Influence of soil water status and atmospheric vapor pressure deficit on leaf gas exchange in field-grown winter wheat. Environ. Bot. 51: 167-179. Yazar, A., and A. Yarpuzlu, (1997). Wheat and cotton yield response to low-quality drainage water and different leaching fractions in the Mediterrranean region of Turkey. In: International Conference on “Water Management: Salinity and Pollution Control Towards Sustainable Irrigation in the Mediterranean Region, Valenzano, Bari, Italy, 22-26 Sept., Vol IV, pp 153-169. Zhang, J., Sui, X., Li, B., Su, B., Li, J., Zhou, D., (1998). An improved water use efficiency for winter wheat grown under reduced irrrigation. Field Crops Research 59: 91-98. Zwart, S.J., Bastiaanssen,W.G.M., (2004). Review of measured crop water productivity values for irrigated wheat, rice, cotton and maize. Agric. Water Management 69, 115-133. 84 USE OF SALINE IRRIGATION WATER FOR PRODUCTION OF SOME LEGUMES AND TUBER PLANTS ** A. Hamdy *, and Y. G. M. Galal ** * IAM-Bari, Italy ** Atomic Energy Authority, Nuclear Research Center, Soil and Water Research Department, Abou-Zaabl, 13759, EGYPT. A. M. Gadalla SUMMARY - Effect of irrigation water salinity on growth and production of some legumes, i.e. faba bean, chickpea, and lentil as well as tuber plants like sugar beet and potatoes was investigated in lysimeter system under green house controlled conditions using drip irrigation system. Chickpea was frequently affected by saline water. Number of pods was decreased gradually with increasing water salinity levels. High levels of salinity negatively affected shoot, root dry matter, seed yield and N accumulated in shoots and roots. A slight difference in seed N was noticed between fresh water and 9 dS/m treatments. Results showed that high levels of salinity negatively affected seed yield and N accumulated in tissue of faba bean. Similar trend was noticed with dry matter of lentil. While, shoot-N was increased at 6 and 9 dS/m. Both leguminous crops were mainly dependent on N2 fixation as an important source of nitrogen nutrition. Under adverse conditions of salinity, the plants gained some of their N requirements from the other two N sources (Ndff and Ndfs). Application of the suitable Rhizobium bacteria strains could be beneficial for both the plant growth and soil fertility via N2 fixation. Sugar percentage in sugar beet tubers was increased with increasing saline irrigation water under different nitrogen strategies. It was slightly increased when N applied at full dose than the splitting one. Addition 75% of water requirements also resulted in high percentage of sugar at all levels of saline irrigation water either N added full dose or splitting doses. Exposure of two varieties of potato to different water salinity levels indicated that total yield, on the base of fresh weight, of Spunta or Nicola tubers was slightly increased by increasing water salinity level up to 6 dS/m. In general, the overall means showed the superiority of Nicola variety over Spunta variety. Also, addition of organic compost in different rates has some significant effects on starch content in tubers. In this respect, gradual 2 increase of tuber starch with increasing salinity levels was noticed with addition of 2.6 kg/m organic matter. In general, Spunta variety showed some superiority in tuber starch over those of Nicola variety tuber. Key words: Drip irrigation, Legumes, N management, Organic amendment, Saline water, Tubers, Water regime, Yield INTRODUCTION Salinity is currently one of the most severe abiotic factors limiting agricultural production. In addition, water demand was increased due to increasing the population and improvement of living standards (Paranychianakisa and Chartzoulakis, 2004). In regions affected by water scarcity such as the Mediterranean basin, water supplies are already degraded, or subjected to degradation processes, which worsen the shortage of water (Chartzoulakis, et al., 2001; Attard, et al., 1996). Therefore, attention had been paid on reusing the low quality water resources in irrigation. In this respect, types of salinity, categories of salt-affected soils, water quality and water classification has been excellently reviewed by Aly (2004). At high substrate salinity, growth depression may originate from inhibited nutrient uptake, transport and utilization in the plant (Lauchli and Epstein, 1990). Legumes have the capacity to derive a considerable proportion of their nitrogen requirement from the atmosphere through symbiosis with Rhizobium. The amount of N2-fixed by legumes-rhizobia symbiosis is greatly influenced by many environmental factors such as temperature, water, soil pH, oxygen content or soil nutrient status (Kvien and Ham, 1985). Saline habitats are N-poor, therefore the N input is very important in these environments (Zahran, 1997). One of the sources of N input in saline soils is N2-fixation (Whitting and Morris, 1986). Higher rates of N2-fixation in saline environment compared to non-saline and 85 agricultural soils were reported (Wollenweber and Zechmeister-Boltenstern, 1989). The low oxygen tension in saline soils may favour the process of N2-fixation, but the diffusion of gases may be impaired at a higher density and water regime in saline soil, an effect that might reduce N2-fixation (Rice and Paul 1971). Sugar beets are salt resistance owing to osmotic adjustment. Physiological adjustments enable the plant in a saline environment to maintain the turgor potential at a similar level as under non-saline conditions. Moisture stress reduced the rate of sucrose concentration to a greater extent in the low-N plants than in the high-N plants (Loomis and Jr. Worker, 1963). Water stress several weeks before harvest of fall-planted beets reduced root yields but increased sucrose percentage. Limited moisture stress to increase sucrose concentration without reducing gross sugar yield can be a profitable practice. Nitrogen (N) management plays an important role in sugar beet production. However, in sugar beets, managing N for a high-yielding and high-quality crop can be difficult. Sugar beet growers can further improve the efficiency of N applications by applying N in multiple applications. Potato (Solanum tuberosum L.) is one of the most important vegetable crops in Egypt, which lie on the head of Egyptian exports menu and one of the national income resources. In the past, it was believed that potato could only be planted in loam soil cultivated, but recent studies showed that there is a possibility of potato production under sandy soil conditions, with high tubers quality (AbouHussein, 1995). Regarding salinity tolerance of potatoes grown in sandy soils, Gong et al. (1996) indicated that irrigating potato plants once a day with saline water reduced plant growth as compared with 3 or 6 irrigations a day. This context mainly focused on the effect of irrigation water salinity on growth and nutritional factors and physiological impacts that limiting the development of different leguminous and tuber crops. MATERIALS AND METHODS Different crops either leguminous, i.e. chickpea, faba bean and lentil or tubers such as sugar beet 3 or potatoes were cultivated under greenhouse conditions. PVC Lysemeter with volume 0.103 m (diameter 0.54 m and depth 0.45 m) was used. A clay textured soil with pH, 8.11; EC, 0.542 dS/m; OM, 2.67%; available water 9.7%, field capacity, 29.7% was used. Experimental layout Leguminous crops Chickpea seeds (Cicer aeritinum cv. Giza 1) were planted and treatments were randomly arranged in 16 containers, with additional batch of treatments were carried out with wheat plant (16 containers), used as a reference crop for quantifying the potential of N2-fixation through the application of isotopic dilution technique. Four salinity levels of irrigation water were used in the experiment namely 1.0 dS/m (freshwater as a control) and three levels of saline water 3, 6 and 9 dS/m. Peat-based inocula of Rhizobium leguminosarum biovar vicea, ICARDA 36 was used for inoculation of the tested crop. The 9 -1 15 15 inoculum has 8x10 cells g peat. N-labelled ammonium sulfate, ( NH4) 2 SO4 5 % atom excess, as -1 N-fertilizer was applied at rate of 20 kg N ha . Similarly, the seeds of faba bean (Vicia faba cv. Giza 388) and Lentil (Lens culinaris cv. Giza 15) were cultivated under the abovementioned 4 levels of saline water. 15N-labelled ammonium sulfate, 15 -1 ( NH4) 2 SO4 10 % atom excess, as N-fertilizer was applied at rate of 20 kg N ha . Wheat crop (Triticum aestivum L. Sakha 69) was used as a reference crop for quantifying N derived from air by the two leguminous crops. This reference crop was fertilized with 100 kg N as (15NH4) 2 SO4 (1% 15N a.e.). Peat-based inocula of Rhizobium leguminosarum biovar vicea, ARC 207 F (Faba bean) and 86 ARC 203 L (Lentil) were used for inoculation of the tested crops. The inoculum has 8 x 10-9 cells g-1 peat. Tuber crops • Sugar beet An experiment was conducted under greenhouse conditions. The set-up consists of 64 lysimeters (4 saline irrigation water treatments, 2 water regimes, i.e. W I=100% and W II=75% from field capacity, 2 nitrogen, i.e. NI=one dose and NII= split doses, and 4 replicates). Sugar Beet (Beta vulgaris L.), Variety GIADA, provided by the International Agronomic Mediterranean Institute, Valenzano, Bari – Italy, from KWS Company, was used as indicator plant. Four qualities of irrigation water were used in the experiment: 0.98 dS/m (Fresh water as a control), 15 and three saline irrigation water treatments 4, 8 and 12 dS/m. Labeled ( NH4) 2 SO4 (5 % a.e.) was -1 added to all lysimeters of Sugar Beet crop at rate of 150 kg N ha . Nitrogen fertilizer was divided into two treatments, the first applied as single dose, 112.5 Kg N/ha, while the second treatment is split into two equal doses of 56.25 Kg N/ha. • Potatoes The set-up consists of 90 Lysemeter (3 saline irrigation water treatments, 3 organic matter, 2 varieties of potatoes (Spunta and Nicola), and 5 replicates. The saline water was prepared by mixing fresh water (0.91dS/m) with seawater (46dS/m) at certain ratios. The electrical conductivity (EC) values of saline water were 0.91dS/m (fresh water control), 3 and 6 dS/m. Three rates of organic matter have been used, OM1, OM2 and OM3 with quantities of 0, 600 and 2 1200g equivalent to 0, 2.6 and 5.2 kg/m , respectively. The chemical analysis of organic matter is: Organic C, 35%; Organic N, 1,2 %; C/N ratio, 29; HA+FA, 8%; Zinc, 80 ppm; salinity, 20 dS/m. Potato (Solanum tuberosum), with two varieties (Spunta & Nicola), provided by the International Agronomic Mediterranean Institute, Valenzano, Bari – Italy, from HZPC Company was cultivated. The cultivated varieties were fertilized with nitrogen which applied at a rate of 200 kg N /ha as ordinary urea (NH2CONH2) and labeled urea (10% a.e.). All leguminous and tuber crops were also fertilized with the recommended doses of phosphorus and potassium fertilizers. The standard methods were used for soil and plant analyses according to Page et al., (1982). Isotope dilution concept was applied for quantification of different portions of nitrogen used by plants (Hardarson et al., 1991). Statistical analysis All data were subjected to ANOVA analysis followed by Duncan's multiple range test (DMRT) according to SAS software program (1987). RESULTS AND DISCUSSION Legume crops Chickpea Yield and growth components of chickpea as influenced by salt stress are listed in Table 1. It is clear that the number of pods decreased gradually with increasing salinity of irrigation water. Raising salinity level resulted in a relative reduction in the number of pods by 10 %, 24% and 31% for 3, 6 and 9 dS/m, respectively. Shoot and root dry matter yield showed a remarkable decrease with increasing salinity level up to 9 dS/m as compared to the fresh water control, but it doesn’t vary so much. Concerning the seed yield, the data show that the total seed yield sharply decreased with increasing 87 salinity levels. For instance, the relative reduction was by 67% caused by rising up to 3 dS/m. The highest reduction was noticed with the high EC unit of 9 dS/m, where 89% of the total seed yield of fresh water treatment was reduced. A similar trend, but to a lesser extent, was recorded with the weight of 100-seed yield. Summation of dry weight (total seed yield + shoot + root) of chickpea plants indicates a gradual reduction with gradual increase in water salinity, by about 36%, 45% and 56% for 3, 6 and 9 dS/m. From the above-mentioned results, we can conclude that the growth and yield components of chickpea plants were adversely affected by salinity stress. Table 1. Number of pods and dry weight of different parts of chickpea plants as affected by the salinity level of irrigation water Salinity (EC) No. Of pods Dry weight (g/Li) Shoot Root D.W. Sum. 24.2 a 147.2 a 50.0 a 379.2 - 59.8 b 21.4 a 142.8 a 41.8 ab 244.4 35.5 24 35.2 c 9.8 b 136.4 a 35.6 b 207.2 45.4 212 d 31 19.2 d 5.8 c 113.3 b 35.0 b 167.5 55.8 258.5 22 74.1 15.3 135.0 40.6 249.6 45.6 Seeds No./Li R.D. (%) Total 100 seed F.W 309 a - 182 a 3 dS/m 277 b 10 6 dS/m 236 c 9 dS/m Average R.D. (%) Means in the same column followed by the same letter are not significantly different at P ≥ 0.05. It is documented earlier (Singh and Saxena 1999) that salinity causes nutritional imbalances and restricts water availability to plants and causes physiological drought, adversely affecting seed yield. Saxena and Rewari (1992) found that the increases in salt concentration not only adversely affected the percentage germination of seeds of chickpea cultivars but also delayed their germination at lower levels of salinity, whereas at higher concentrations the percentage germination and radical length were reduced. The mean tolerance index (MTI) estimated for chickpea cultivars grown under EC of 2, 4, 6 and 8 dS/m (Field study, Dua, 1992) indicates that although the germination percentage in chickpea was not affected up to EC of 8 dS/m, sensitivity to salinity increased as the plants grew. Other authors have also reported that chickpea was less sensitive to salinity at germination than at later growth stages (Sharma et al., 1982). Considering seed yield, Dua (1992) verified that the adverse effect of salinity on seed yield/plant results mainly from a reduction in the number of pods/plant and the number of seeds/plant rather than in 100-seed weight. Thus, this indicated that plants were more sensitive to salinity at seed setting (flowering) than at the maturity stage. Faba bean As presented in Table 2, the salinity levels did not affect the number of pods of faba bean significantly. The data show a relative increase in the number of pods by 8% and 13% when saline water of 3 dS/m and 6 dS/m, respectively, was used. This result may give evidence that faba bean is somewhat tolerant to experimental salinity levels of water. At the higher level (EC 9 dS/m), the number of pods tended to decrease as compared to other salinity levels, but is still identical to that of the fresh water control. In other words, the production of pods is not affected by increasing salinity of irrigation water. In contrast, high EC units negatively affected the total and 100-seed yield. It means that high EC units affected faba bean. It seems also that faba bean plants is not affected by the lower level of salinity, whereas the seed yield was identical in fresh water and 3 dS/m. A similar trend was noticed with either shoot or root dry weight, indicating the inhibition of growth by increasing water salinity. The overall average of relative reduction of faba bean total dry weight (seeds + shoot + root) resulted in 15% and 22% reduction, as affected by 6 and 9 dS/m salinity, respectively. 88 Table 2. Number of pods and dry matter accumulated in different parts of faba bean plants irrigated with saline water No. of pods Salinity (EC) Dry weight (g/Li) D.W. Sum. R.D. (%) 44.2 a 317.8 - 183.5 a 38.2 a 320.6 + 0.88 77.0 151.0 bc 31.0 a 269.2 - 15.3 79.2 a 82.2 138.4 c 30.1 a 247.7 - 22.1 90.9 83.3 162.0 35.9 288.8 - 12.2 Seeds No./Li R.D. (%) Total 100 seed Shoot Root F.W 40 a - 98.4 a 87.4 175.2 ab 3 dS/m 43 a +8 98.9 a 86.4 6 dS/m 45 a + 13 87.2 a 9 dS/m 40 a - Average 42 7 Means in the same column followed by the same letter are not significantly different at P ≥ 0.05. In a greenhouse experiment, faba bean was found to be sensitive to the high level of NaCl (1000 ppm) were its dry weight of shoot and root was decreased (El-Fouly et al., 2001). Hajji et al., (2001) + explained that growth inhibition of bean was associated with excess accumulation of Na in leaves + ++ and attributed to depletion of K and Ca in this organ. This suggests that Cl in the medium inhibited the adsorption of essential nutrients. Thus, it appears that these elements were limiting for growth in + ++ the presence of NaCl because salinity probably inhibited the transport of K and Ca from roots to + shoots. In short, under saline conditions, growth is primarily limited by osmotic not by excessive Na accumulation. The results obtained in our study show that despite the particular/notable increase in the number of pods with increasing salinity level, the overall average of dry matter accumulation tended to decrease. This finding was confirmed by the reduction in life cycle long of faba bean plants with salinity level (Fig.1). 140 Faba bean Plant Hieght(cm) 120 100 Chickpea Lentil 80 60 40 20 0 20 40 60 80 100 20 40 60 80 100 20 40 60 80 100 Time period FW 3 6 9 Fig. 1. Changes in plants height with times as affected by salinity levels of irrigation water 89 Lentil Lentil is known to be sensitive or moderately tolerant to salt stress. The effect of EC units of irrigation water on growth components is reported in Table 3. Dry weight of pods revealed the sensitivity of lentil plants to salinity. The decline in pod dry weight was recorded even with the lowest salinity level (3 dS/m). The increase in salinity was followed by decreasing dry weight of pods by 21%, 41% and 54% for 3, 6 and 9 dS/m, respectively, as compared to the fresh water treatment. A similar trend was observed with shoot and root dry weight and seed yield of lentil plants. The summation of plant dry weight (shoot + root + seed) indicated a sharp decrease with increasing salinity up to 9 dS/m, by 32% from those recorded with fresh water treatment. Our results are in accordance with those reported by Yasin and Zahid (2000) who found that lentil crop was sensitive even at low level of salinity. Similarly, they found a linear decrease in shoot biomass, of 55% and 85%, respectively, at 4 and 8 dS/m salinity levels. Under greenhouse conditions, lentil dry weight was higher at 3.1 dS/m than at 4.3 and 6 dS/m salinity levels (IAEA, 1995). In a two-year field experiment conducted under Bangladesh conditions, lake water of an EC ranging from 1.5 to 4.5 dS/m was used for irrigation of lentil crop. The yield of lentil irrigated with lake saline water was found to be lower as compared to average national yield recorded under Bangladesh conditions (Rahman, IAEA 1995). Result of screening experiments of lentil conducted in greenhouse conditions showed that lentil varieties can with stand various levels of soil and/or water salinity from 0.63 to 6.0 dS/m (IAEA, 1995). Table 3. Effect of changes in EC units on pod weight, dry matter accumulation in different lentil parts W. Of pods Dry weight (g/Li) 100 seed Shoot Root D.W. Sum. R.D. (%) 51.5 a 3.0 a 68.0 a 26.6 b 146.1 - -20.8 38.0 b 2.6 b 67.9 a 33.6 a 139.5 -4.5 32 c -41.4 24.4 c 2.0 c 68.1 a 17.2 c 109.7 -24.9 9 dS/m 25 d -54.4 15.0 d 1.6 d 68.5 a 16.0 c 99.5 -31.9 Average 39 -38.9 32.2 2.3 68.1 23.4 123.7 -20.4 Salinity (EC) Seeds (g/Li) R.D. (%) Total F.W 54 a - 3 dS/m 43 b 6 dS/m Means in the same column followed by the same letter are not significantly different at P ≥ 0.05. Portions of Nitrogen Derived from Different N-sources Chickpea In this part of the present study, we aimed at applying the stable heavy isotope of nitrogen N-15 to distinguish the different sources of nitrogen derived to the chickpea plants and to estimate exactly how much N could be compensated by the different sources. In this respect, the portions of N derived from air, fertilizer and soil are presented in Table 4. 15 The obtained data showed a slight variation in N atom excess of chickpea straw with salinity 15 levels. A remarkable decrease in the percent of N atom excess was noticed in the case of chickpea 15 seeds as affected by gradient/gradual increase in salinity levels. These percentages of N a.e., were significantly lower than those recorded with wheat as a reference crop used for quantifying the biological nitrogen fixation (BNF) when applying the isotope dilution (A-value) technique. The calculation of the percentage and absolute values of N derived from chemical fertilizer added, showed slight increase with 3, 6 and 9 dS/m treatments, while they were notably higher than the fresh water control, when straw-N was considered. In contrast, seed-N derived from fertilizer tended to decrease with increasing water salinity levels. These results indicate that most of the fertilizer N yield was accumulated in straw of chickpea than seeds. Generally, the portion of N derived from fertilizer to either straw or seeds doesn’t exceed 12 % of the total N uptake. 90 The opposite was observed with the fraction of N derived from fixation, whereas more than 80% and 70% of the nitrogen accumulated by straw and seeds, respectively derived from air. Portion of N2-fixed in straw of chick-pea decreased with the level of 3 dS/m as compared to the fresh water control, then it tended to increase with both 6 and 9 dS/m treatments but is still lower than fresh water. Considering the N2-fixation by seeds, the data indicate stability of % Ndfa with increasing salinity, except the treatment of 6 dS/m where it decreased with respect to other treatments and even the control. Absolute figures of N fixation revealed that the relationship of Rhizobium leguminosarum – chickpea symbiosis is obviously affected by the adverse conditions of saline water used. In this respect, Saxena and Rewari (1992) explained that symbiotic performance in saline soil depends on the salt-tolerance of both the host and the micro-symbiont. We agree with this conclusion since our results indicated a good performance of chickpea, Rhizobium symbiosis, under salinity conditions given. The reduction in the quantities of N2-fixation with increasing salinity seems to be related to the reduction in plant growth (Kumar and Promila, 1983), disturbed metabolism, and imbalanced nutrient acquisition (Kawasaki, et al., 1983). Soil-N came to the next as a fraction of nitrogen demand. It increased with increasing water salinity levels. This fraction may compensate the reduced quantities of N2 derived from air under high level of salinity. In other terms, under adverse conditions, which may reduce the potential of N2 fixation, the plant turned to depend on other N fractions like the Ndf soil. From the above-mentioned data, it may be concluded that chick-pea plants were dependent on the different N sources in the following order: Ndfa > Ndfs > Ndff Also, it may be stated that the unsuitable abiotic conditions that inhibited Pfix could push the grown plant to profit from other N sources to avoid N-nutrition disorders. Table 4. Nitrogen derived from air (Ndfa), fertilizer (Ndff) and soil (Ndfs) in chickpea straw and seeds as affected by salinity conditions Treatment N a.e. Nitrogen sources Ndfa g/Li % g/Li Straw 0.17 2.53 82.1 0.28 1.49 62.8 0.35 2.09 70.5 0.31 1.87 72.24 Seeds 0.14 1.18 71.28 0.16 1.46 71.0 0.08 0.70 67.1 0.04 0.48 72.87 Reference crop Straw 0.82 0.52 0.86 1.09 Seeds 1.81 1.62 1.86 1.57 - Ndff 15 % F.W. 3 dS/m 6 dS/m 9 dS/m 0.581 0.590 0.596 0.598 5.62 11.8 11.92 11.96 F.W. 3 dS/m 6 dS/m 9 dS/m 0.431 0.402 0.386 0.310 8.62 8.04 7.72 6.20 F.W. 3 dS/m 6 dS/m 9 dS/m 0.695 0.699 0.772 0.791 69.5 69.9 77.2 79.1 F.W. 3 dS/m 6 dS/m 9 dS/m 0.682 0.657 0.605 0.597 68.2 65.7 60.5 59.7 Ndfs % g/Li 12.33 25.41 17.60 15.80 0.38 0.60 0.52 0.41 20.1 20.96 25.18 20.93 0.33 0.43 0.26 0.14 30.5 30.1 22.8 20.9 0.36 0.22 0.26 0.29 31.8 34.3 39.5 40.3 0.85 0.85 1.21 1.06 91 Faba bean The data of N derived from the different sources and taken up by faba bean straw and seeds, (Table 5) show a trend similar to that observed with chickpea plants-N derived from fertilizer was negatively affected by increasing salinity levels. % Ndff didn’t vary so much as in straw but drastically decreased in seeds at the highest (6 and 9 dS/m) levels of water salinity. In the same time, faba bean plants take up a reasonable amount of nitrogen from soil. This component was higher under low levels of salinity than under the highest ones. More Ndfs was found in seeds as compared to straw-N. Nitrogen derived from air (Ndfa) seems to be the main source of N utilized by both straw and seed organs. This source of N nutrition compensated about 70% and more than 80% of the N needed for faba bean demand. Also, N2-fixation by seeds was higher, to some extent, than by straw. This fraction reflects that faba bean was tolerant to levels of 3 and 6 dS/m when N2-fixed by seed was considered. Table 5. Nitrogen derived from air (Ndfa), fertilizer (Ndff) and soil (Ndfs) in faba bean straw and seeds as affected by salinity conditions Nitrogen sources Treatment Ndff 15 N a.e. % F.W. 3 dS/m 6 dS/m 9 dS/m 0.611 0.621 0.631 0.640 12.22 12.42 12.62 12.80 F.W. 3 dS/m 6 dS/m 9 dS/m 0.605 0.501 0.298 0.210 12.1 10.02 5.96 4.20 Ndfa g/Li Straw 0.45 0.49 0.33 0.41 Seeds 0.61 0.50 0.25 0.11 Ndfs % g/Li % g/Li 60.97 60.84 68.74 70.29 2.22 2.39 1.83 2.27 26.81 26.74 18.64 16.91 0.98 1.05 0.49 0.55 59.69 63.82 74.52 81.62 2.99 3.21 3.10 2.00 28.21 26.16 19.52 14.18 1.41 1.31 0.81 0.35 In this respect, Cordovilla et al. (1995) stated that the host tolerance appeared to be a major requisite for nodulation and N2 fixation of faba bean cultivars grown under salt stress. They also found that some cultivars have the ability to sustain nitrogen fixation under saline conditions (salt tolerant genotype). The absolute value of N2 fixed by faba bean seeds was higher than those recorded for chickpea plant suggesting the specific Rhizobium-host relationship. In conclusion, faba bean as well chickpea are mainly dependent on N derived from fixation for offering/meeting its nitrogen requirements. Nitrogen derived from soil came next and followed by nitrogen derived from fertilizer. 15 Also, from the obtained data of N analysis, it is clear that N2 fixation potential should take place (should be part of) in the program of integrated plant nutrition systems and soil fertility improvement especially under adverse conditions of salinity stress. Similarly, may I have the chance to advise the properly selection of both Rhizobium bacteria strains and the suitable host plant tolerant to salinity stress. Lentil The data in Table 6 present the effect of salt stress on nitrogen derived from fertilizer, air and soil and taken up by straw and seeds of lentil plants. The effect of water salinity on fertilizer-N derived to straw was unclear. In contrast, the decrease in the amount of N derived from fertilizer and assimilated by lentil seeds was noticeable. Our results, to some extent, are in agreement with those reported by Rahman (1995) who found that the percentage of N derived from fertilizer to lentil seeds does not exceed 12% under irrigation with normal water, but tended to decrease when lake saline water (10 dS/m) was applied. Soil-N derived to lentil plants ranged from 6% to 28% as affected by salinity levels. The highest percentage of soil-N was obtained with 3 dS/m and 6 dS/m for straw and seeds, respectively. It seems that lentil plants grown under salinity stress was more dependent on soil-N than fertilizer-N. 92 Concerning the N2-fixation by straw and seeds of lentil, the data show a negative response to gradient increase in water salinity, especially in seed-N. Seeds were mainly dependent on N derived from air since it accounted for 87% and tended to decrease with increasing salinity levels. The portion of N2 fixed obtained in the present study is in agreement with the value reported earlier by Rahman (1995). It is clear, that the improvement of lentil growth, in general, is attributable to fixation of atmospheric N2 by lentil due to the application of the appropriate Rhizobium strains. As mentioned above, we also advise the application of inoculation technology to improve both the soil fertility and plant growth especially under the adverse saline conditions. Table 6. Nitrogen derived from air (Ndfa), fertilizer (Ndff) and soil (Ndfs) in lentil straw and seeds as affected by salinity conditions Treatment Ndff 15 N a.e. % F.W. 3 dS/m 6 dS/m 9 dS/m 0.591 0.651 0.663 0.671 11.82 13.02 13.26 13.42 F.W. 3 dS/m 6 dS/m 9 dS/m 0.342 0.310 0.287 0.285 6.84 6.20 5.74 5.70 Nitrogen sources Ndfa g/Li % g/Li Straw 0.16 0.16 62.24 0.17 0.17 58.4 0.22 0.22 67.16 0.20 0.20 68.85 Seeds 0.16 0.16 87.47 0.11 0.11 77.62 0.05 0.05 75.52 0.03 0.03 73.06 Ndfs % g/Li 25.94 28.04 19.58 17.73 0.34 0.37 0.32 0.26 5.69 16.18 18.74 21.24 0.16 0.29 0.18 0.12 Sugar beet Sugar % and yield (kg/h) Sugar % and yield (kg/h) as affected by different water salinity, N as added at one time or splitting and irrigation water percent (100 or 75% of field capacity) were presented in Table 7. Generally, the data indicate that sugar % increased with increasing salinity levels of irrigation water under both NI and NII treatments. It seems that sugar% was higher in case of NI than NII under different salinity levels, when W I was concerned. Opposite direction was noticed with W II water treatment. Data recorded in Table 7 show that sugar yield (kg/ha) increased by increasing water salinity. The increment of sugar yield was (8.3 and 7.7%) under application of N as one time and irrigation by saline water (4 and 12 dS/m), respectively, comparing with FW, under W I treatment. While in case of NII the rate of increase was (13.2, 11.5 and 33.1 %) for (4, 8 and 12 dS/m), respectively compared to fresh water treatment. At the same time, irrigating sugar beet plants with 75% of water field capacity also lead to a remarkable increase in sugar yield either under NI or NII where the increment of sugar yield in case of NI was (24.7, 52 and 39%) for (4, 8 and 12 dS/m of water salinity), respectively comparing to FW treatment. The same trend was noticed in case of NII but to somewhat higher extent. Significant variation between treatments was presented in Table 8. Our results are in harmony with those obtained by El-Hawary (1990) who found a significant increase in sugar yield per plant due to nitrogen application. He added that, the N application at rate of 90 kg N/feddan after 40 days from sowing date (N3-treatment) gave the highest average of sugar yield per plant. These results might be attributed to the favorable effect of nitrogen on root volume and fresh weight of root / plant. Wiesler et al. (2002) reported that increasing fertilizer N rates reduce sucrose concentration and sugar yield. Although, we did not apply different doses of N fertilizer but only split the recommended dose, we believe that this technique has the advantage to save N-fertilizer and in the same time offers preferable conditions, in combination with water regime, to remarkable production of sugar. 93 Table 7. Effect of salinity levels, N doses and water percent on sugar yield (% and kg/ha) of sugar beet plants Salinity levels FW 4 dS/m 8 dS/m 12 dS/m Average WI (%) kg/ha NI NII 5886.1 5192.2 6375.3 5878.6 5788.1 5787.9 6340.2 6912.2 6097.4 5942.7 NII 14.0 16.3 17.8 20.4 17.1 NI 16.0 17.4 19.0 21.2 18.4 W II (%) NI 13.7 15.3 18.8 19.6 16.9 NII 15.7 18.2 20.5 23.3 19.4 kg/ha NI NII 4753.4 6366.0 5928.1 6745.1 7226.0 7604.4 6607.5 7717.2 6128.7 7108.2 Table 8. Summary of ANOVA –Significance of sources of variation and variance of error of studied characters for plant root Sources of variation Water treatments (W) Water salinity level (S) Nitrogen (N) Interaction W * S Interaction W * N Interaction N * S Interaction W * N * S Error D.F. 1 3 1 3 1 3 3 60 Sugar content Sugar yield % (t/ha) ns ** Ns Ns ** Ns ns 0.8166 * * ns * ** * ** 0.1348 Potatoes • Total yield of tuber on the base of fresh weight (t/ha) As presented in Table 9, the total yield of Spunta tubers was slightly increased by increasing water salinity level up to 6 dS/m. Similar trend was noticed when organic addition rate concerned. Nicola tubers showed similar trend as those of Spunta variety, but the increments affect by salinity and decrements caused by addition of organic matter were much remarkable than in case of Spunta variety. In general, the overall means showed the superiority of Nicola variety over Spunta variety. Table 9. Effect of water salinity and organic matter levels on total yields tuber fresh weight (t/ha) of Spunta and Nicola potatoes varieties. 94 Organic Matter Level 2 (kg/m ) F.W 0 2.6 5.2 Mean 40.0 41.4 39.8 40.4 0 2.6 5.2 Mean 47.6 44.8 42.4 44.9 Water salinity level (dS/m) 3 Spunta 42.2 41.8 40.7 41.6 Nicola 50.8 45.6 44.9 47.1 6 Mean 42.9 44.2 42.7 43.3 41.7 42.5 41.1 52.4 46.3 46.1 48.2 50.3 45.6 44.4 Concerning the yield and tuber size distribution, Porter et al. (1999) reported that, the yield increases in response to the amended treatments (green manure) may be due to increased availability and/or changes in soil bulk density, water stable aggregates or other soil physical properties. The soil amendment treatments increased soil nutrient concentrations and aggregation. Also supplemental irrigation increases tuber size during the drier growing season. Maintaining soil water after tuber initiation increased the percentage yield of tuber than 5.7cm in diameter. Soil amendment treatments (green manure) significantly increased tuber size. These results are sometimes on line with our results of tuber distribution. Iqbal et al. (1999) studied the yield response of potato to planned water stress; the results obtained showed that, the timing of water stress influenced the tuber yield. The stress imposed at ripening stage caused the lowest reduction in yield whereas that imposed at early development caused the greatest yield reduction followed by the tuber formation stage. • Starch content (g/100g FW) Increasing water salinity level up to 3 and 6 dS/m induced relative decrease in Spunta starch 2 under 0 organic matter by about 11.5 and 14.1%, respectively (Table 10). Addition of 2.6 kg/m 2 organic matter had decreased the tuber starch, except the treatment of 5.2 kg/m organic matter under 6 dS/m level where the starch was vigorously increased. Starch in Nicola tuber under noorganic amendment, was decreased with increasing salinity level up to 3 dS/m, and then increased 2 with increasing salinity to 6 dS/m. Similar trend was noticed with 5.2 kg/m organic matter level. 2 Gradual increase of tuber starch with increasing salinity levels was noticed with addition of 2.6 kg/m organic matter. In general, Spunta variety showed some superiority in tuber starch over those of Nicola variety tuber. Our results of starch are in agreement with those obtained by Silva et al. (2001). Starch level in two potatoes (S.tuberosum and S.curtilobum) was constant with salinity levels (0, 25, 50, 75 and 100 -1 mmoll NaCl). The starch levels in both varieties of potatoes (S.tuberosum and S.curtilobum) remained constant under all salt levels. Also, organic solutes such as soluble carbohydrates have + been suggested to play an important role as osmoprotectants counteracting the toxic effects of Na and Cl in the shoots under salt stress (Evers et al., 1997). Table 10. Effect of water salinity and organic matter levels on starch (g/100g FW) of Spunta and Nicola potatoes varieties Organic Matter Level (kg/m2) F.W 0 2.6 5.2 Mean 17.6 15.4 14.7 15.9 0 2.6 5.2 Mean 13.8 10.7 15.4 13.3 Water salinity level (dS/m) 3 6 Mean Spunta 14.9 14.3 15.6 15.4 13.9 14.9 13.6 16.0 14.8 14.6 14.7 Nicola 11.3 14.9 13.3 12.8 14.6 12.7 12.6 14.9 14.3 12.2 14.8 CONCLUSION Results obtained in this study confirm the reuse of low quality irrigation water mainly saline one, which may overcome the gab between water charge and requirements for agricultural practices. As shown above, the use of saline water in irrigation of some salt-tolerant plants may result in economical production of such economical legumes and/or tuber crops. 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(2001) Microtuberization of Andean Potato Species (Solanum spp.) as affected by salinity. Scientio Hort.89: 91-101. Singh, K.B. and Saxena, M.C. (1999) Chickpeas. The Tropical Agriculturalist services. Mac Millan and ICARDA, MacMillan Education Ltd. Whitting, G.I. and Morris, I.T. (1986) Soil Biol. Biochem. 18, 515-521. Wiesler, F; Baure, M.; Kamh, M., Engles, T. and Reusch, S. J. (2002) Plant Nut. Soil Sci. , 165, 93 – 99. Wollenweber, B. and Zechmeister-Boltenstern, S. (1989) Botanical Acta 102: 96-105. Yasin, M. and Ashraf Zahid, M. (2000) Genotypic behavior of lentil cultivars towards salinity. Book of Abstract on ispsa, April 10-12, 2000, Islamabad, Pakistan. Zahran, H.H. (1997) Biol. Fertil. Soils 25, 211-223. 97 SEA WATER STRESS AFFECTS MITOCHONDRIAL PROLINE OXIDATION BUT NOT ALTERNATIVE OXIDASE ACTIVITY IN DURUM WHEAT GERMINATING SEEDLINGS , , , M.N. Laus*, Z. Flagella* ** , D. Trono***, M. Soccio* ***, N. Di Fonzo*** and D. Pastore* ** *Dipartimento di Scienze Agroambientali, Chimica e Difesa Vegetale, Facoltà di Agraria, Università di Foggia, Via Napoli 25, 71100 Foggia, Italy **Centro di Ricerca Interdipartimentale BIOAGROMED, Via Napoli 52, 71100 Foggia, Italy ***Istituto Sperimentale per la Cerealicoltura – C.R.A., SS 16 Km 675, 71100 Foggia, Italy SUMMARY - Durum wheat (Triticum durum Desf.) is a species well adapted to the Mediterranean environments, where it often faces salt stress due to increasing soil salinity. Recently, the central role of mitochondria in the adaptation to environmental stresses at sub cellular level has emerged. The mitochondrial defence mechanisms may contribute to depict a durum wheat plant ideotype showing higher water use efficiency under water and/or salt stress and able to be irrigated with brackish water. In particular, two important mitochondrial mechanisms involved in resistance to environmental stresses are: (i) the inhibition of proline oxidation (that parallels accumulation of proline as an osmoprotectant in the cell); and (ii) the control exerted by Alternative Oxidise (AOX) of harmful reactive oxygen species generated under stress. Durum wheat mitochondria (DWM) from early seedlings were used to study these physiological mechanisms under salt stress. Seedlings were germinated both in distilled water and in two different diluted sea water solutions, leading to either moderate or severe damage to growth. To assess the contribution of the osmotic component of stress (water stress), a parallel investigation was performed by using hyperosmotic mannitol solutions. Comparison of proline and succinate oxidation by DWM showed that early inhibition of proline oxidation should be considered a mitochondrial adaptation to stress rather than a damage to oxidative properties, while, under our experimental conditions, no increase in AOX activity under stress was observed. In conclusion, early inhibition of proline oxidation may be a useful character enhancing tolerance to salt and water stress in durum wheat. Key words: Saline stress, water stress, durum wheat, mitochondria, proline, alternative oxidise. RESUME - Le blé dur (Triticum durum Desf.) est une espèce bien adaptée au milieu méditerranéen où il est souvent exposé au stress salin à cause d’une teneur en sel croissante dans le sol. Ces dernières années, le rôle central des mitochondries dans l’adaptation au stress environnemental au niveau subcellulaire s’est manifesté d’une manière de plus en plus évidente. Les mécanismes de défense des mitochondries pourraient contribuer à définir un idéotype de blé dur ayant une plus haute efficience d’utilisation de l’eau en conditions de stress hydrique et/ou saline et pouvant être irrigué à l’eau saumâtre. En particulier, deux principaux mécanismes contribuent à la résistance au stress environnemental: (i) l’inhibition d’oxydation de la proline (qui accompagne l’accumulation de la proline en tant qu’osmoprotecteur chez la cellule); et (ii) le contrôle, exercé par l’Oxydase Alternative (AOX), des espèces réactives délétères dérivées de l’oxygène qui sont engendrées en conditions de stress. Nous avons utilisé les mitochondries du blé dur (DWM) des jeunes plantes pour étudier ces mécanismes physiologiques en conditions de stress salin. La germination des jeunes plantes a eu lieu tant dans l’eau distillée qu’en deux différentes solutions diluées d’eau de mer, ce qui a provoqué un dégât de modéré à grave sur la croissance. Pour évaluer la contribution de la composante osmotique du stress, nous avons mené une expérience parallèle en utilisant les solutions de mannitol hyperosmotique. La comparaison de l’oxydation du succinate et de la proline par les DWM a montré que l’inhibition de l’oxydation de la proline devrait être considérée une adaptation mitochondriale au stress plutôt qu’un dégât aux propriétés oxydatives, tandis que dans nos conditions expérimentales nous n'avons observé aucune augmentation de l’activité d’AOX. En conclusion, l’inhibition d’oxydation de la proline pourrait être un caractère utile qui améliore la tolérance au stress hydrique et salin chez le blé dur. Mots clés: Stress salin, stress hydrique, blé dur, mitochondrie, proline, oxydase alternative. 99 INTRODUCTION The increase in salt content due to intrusion of sea water into aquifers leads to an increase of salinity of the agricultural soils, which reduces plant growth and crop productivity in many arid and semi-arid regions of the word (McKersie and Leshem, 1994). Uptake and compartmentation of ions, as well as the production of compatible solutes, i.e. osmotic adjustment, occurring under salt stress are linked to ATP consumption. In the light of this, the effect of salt stress on ATP production is expected to be crucial (for refs. see Flagella et al., 2006). The two sub cellular organelles devoted to massive ATP synthesis are chloroplasts and mitochondria, but the effect of salt and water stress has been deeply investigated only in chloroplasts; more recently, the central role of mitochondria in stress resistance has emerged (Pastore et al., 2007). In order to carry out a specific investigation on the effect on mitochondrial function of salt and water stress, we have chosen durum wheat early seedlings as a suitable experimental model system. In fact, mitochondrial ATP production plays an essential role in germinating seedlings and is very important for the establishment of the initial plant stand. Moreover, durum wheat is a species well adapted to the Mediterranean environments, where salt stress due to seawater intrusion into aquifers is an increasing problem (Rana and Katerji, 2000). This crop may experience salt stress when cultivated in rotation to a crop irrigated with salt water. In this case, the highest salinity level is faced during germination and seedling establishment rather than in the later developmental stages, where spring and winter rainfall prevents salt stress occurrence by leaching excess salt (Caliandro et al., 1991); therefore, salt stress occurs during the early phase of seedling growth, when mitochondrial ATP synthesis plays a key role. Recently, we have shown that durum wheat mitochondria (DWM) from young seedlings are an early target of salt stress; in particular, the inhibition of proline oxidation was found to precede damages to mitochondrial intactness and functionality (Flagella et al., 2006). This inhibition is consistent with proline accumulation in the cell as an osmoprotectant. Anyway, whether inhibition of proline oxidation in DWM may be considered a very early damage or an adaptative response is still uncertain. A second research line we developed in the recent years deals with DWM ability to counteract oxidative damage caused by environmental stresses. DWM possess three active energy dissipating systems, namely the plant mitochondrial potassium channel, PmitoKATP (Pastore et al., 1999a), the plant uncoupling protein, PUCP (Pastore et al., 2000) and the Alternative Oxidase, AOX (Pastore et al., 2001); all the three proteins are able to prevent high mitochondrial membrane potential (∆Ψ) generation and, as a consequence, they are able to dampen the production of harmful reactive oxygen species (ROS) by DWM. We have recently demonstrated that PmitoKATP and PUCP may control excess ROS production when young etiolated seedlings suffer salt and water stress (Trono et al., 2004), while, to date, no information about AOX activity under these conditions is available. In the present paper we have reinvestigated the inhibition of proline oxidation by comparing proline and succinate oxidation by DWM obtained from seedlings subjected to salt stress (applied using diluted sea water solutions) and water stress (applied using hyperosmotic mannitol solutions). Interestingly, to gain novel information, we studied both washed mitochondria (i.e. a crude mitochondrial fraction obtained via differential centrifugation) and purified mitochondria (i.e. the mitochondrial fraction obtained after passage of washed organelles throughout a Percoll gradient). In fact, in our opinion, the use of both washed and purified mitochondria may be advisable to obtain a more integrated interpretation of the inhibition of proline oxidation under stress. Furthermore, we checked AOX activity in DWM from sea water-stressed and water-stressed young seedlings. We suggest that the comprehension of the mechanisms acting at mitochondrial level to counteract salt and water stress may strongly contribute to depict an advanced durum wheat plant ideotype. The addition of novel proper metabolic and biochemical traits to classical useful morpho-physiological traits may make the new plant able to better grow and yield in semiarid areas also under moderate salt stress. MATERIALS AND METHODS All reagents were purchased from SIGMA Chemical Co. (St. Louis, MO). Synthetic seawater was obtained by dissolving a commercial sea salt (SPERA & Co, Margherita di Savoia, Italy) in distilled 100 water to obtain a solution containing 504 mM Na+, 10 mM K+, 54 mM Mg2+, 31 mM SO42-, 540 mM Clas evaluated by DIONEX DX 600 analysis (Flagella et al., 2006). Durum wheat (Triticum durum Desf. cv Ofanto) seeds used in this work were supplied by the Experimental Institute for Cereal Research of Foggia. Stress was induced by using different sea water dilutions (salt stress) or hyperosmotic mannitol solutions (water stress): (i) solutions having osmotic potential equal to -0.62 MPa (22% sea water, . -1 electrical conductivity (E.C.) equal to 12 dS m , or 0.25 M mannitol), which induce moderate stress; . -1 (ii) solutions having osmotic potential equal to -1.04 MPa (37% sea water, E.C. equal to 20 dS m , or 0.42 M mannitol), which induce severe stress (Francois and Maas, 1994; Trono et al., 2004; Flagella et al., 2006). Iso-osmotic concentration of salt and mannitol solutions were checked by a vapour pressure osmometer Roebling, type 13. Durum wheat seeds (300 g) were sown on a distilled water-saturated polyurethane foam sheet covered with a Whatman filter paper. Seeds were dark-grown for 48 h in a Heraeus HPS 1500 incubator at 25 °C and 85% relative humidity; then early seedlings (length of shoot about 0.3 cm) were used to obtain mitochondria. Stressed seedlings were germinated as described for control seedlings except that water was substituted with the sea water dilutions or mannitol solutions as above described. Stressed seedlings were harvested when they reached the same shoot length of the control (0.3 cm), after three and four days for the moderate and severe stress intensity, respectively. Etiolated early seedlings (about 50-60 g) were removed from seeds, then mitochondria were isolated according to Pastore et al. (1999b) with minor modifications. The grinding buffer was 0.3 M mannitol, 4 mM cysteine, 1 mM ethylenediaminetetraacetic acid (EDTA), 30 mM 3-(N-morpholino) propanesulfonic acid (MOPS) (pH 7.50), 0.1% (w/v) defatted bovine serum albumin (BSA), 0.6% (w/v) polyvinylpyrrolidone (PVP)-360; the washing buffer was 0.3 M mannitol, 1 mM EDTA, 10 mM MOPS (pH 7.40), 0.1% (w/v) defatted BSA. The fraction of washed mitochondria was further purified by isopycnic centrifugation in a self-generating density gradient, consisting of 0.3 M sucrose, 10 mM TrisHCl (pH 7.20) and 28% (v/v) Percoll (colloidal PVP-coated silica, Amersham Pharmacia Biotech), combined with a linear gradient of 0% (top) to 10% (bottom) PVP-40. Mitochondrial protein content was determined by the method of Lowry, using BSA as a standard. Oxygen uptake rate was measured at 25 °C with a GILSON Oxygraph model 5/6-servo Channel pH 5, equipped with a Clark-type electrode (5331 YSI, Yellow Spring, OH) in 1.5 mL of a medium consisting of 0.3 M mannitol, 5 mM MgCl2, 10 mM KCl, 0.1% (w/v) defatted BSA, and 10 mM sodium phosphate buffer (pH 7.20). As respiratory substrates, either 10 mM succinate or 20 mM proline were used. In the course of substrate oxidation, successive additions of limited amount of ADP were carried out in order to evaluate: (i) the respiratory control (RC) ratio, i.e. the ability of ADP to control the oxygen uptake rate expressed as a ratio between the rate measured in the presence of ADP (state 3) and the rate measured after ADP consumption (state 4); and (ii) the ADP/O ratio, i.e. the ratio between the nmol of phosphorylated ADP and the natom of oxygen consumed (see Flagella et al., 2006). AOX activity in succinate oxidising DWM was evaluated at 25 °C by using the above described oxygen uptake medium, as a ratio between cyanide insensitive (V+KCN) and cyanide sensitive (V-KCN) oxygen uptake rate, as reported in Fig. 2. The intactness of mitochondrial membranes was evaluated oxygraphically (outer membrane), on the basis of cytochrome c oxidase latency, and photometrically (inner membrane), on the basis of malate dehydrogenase latency (see Trono et al., 2004). ∆Ψ was monitored at 25 °C by measuring safranin O fluorescence changes at λex=520 nm and λem=570 nm, as reported in Flagella et al. (2006). The reaction mixture (2 mL) contained 0.3 M mannitol, 5 mM MgCl2, 0.1% (w/v) defatted BSA, 10 mM MOPS (pH 7.20), 2.5 µM safranin O and 0.1 -1 mg ⋅ mL DWM protein ([safranin O]/[DWM protein] ratio value of 25). 101 RESULTS AND DISCUSSION In order to gain some insight into plant bioenergetics under salt and water stress, experiments were carried out by using the moderate salt sensitive species durum wheat (Triticum durum Desf.). Seedlings were germinated in two different diluted sea water solutions, 22% and 37% sea water, leading to moderate and severe damage to seedling growth, respectively (Trono et al., 2004; Flagella et al., 2006). In order to assess the contribution of the osmotic component of the stress resulting in a water stress, a parallel investigation was performed on seedlings germinated in 0.25 and 0.42 M mannitol solutions, iso-osmotic with the two seawater solutions. As for the DWM isolation protocol, a paper concerning hyperosmotic stress-adapted potato cells shows that the isolation protocol giving better mitochondria needs the use of media showing an osmolarity close to the one of the cells, as evaluated by plasmolysis experiments (Fratianni et al., 2001). Unfortunately, the determination of tissue cell osmolarity from seedlings under our conditions is not a simple matter. Therefore, we isolated mitochondria from stressed seedlings by using the same media suitable for the control ones. In the light of this, due to the non-isotonic isolation media used, washed DWM from stressed seedlings may result in part artificially damaged by the isolation procedure; this could lead to an overestimation of the mitochondrial damages due to stress. On the other hand, the purification of these organelles leads to a selective recovery of a population of highly intact and fully functional mitochondria; therefore, purified mitochondria represent better organelles and may give underestimation of the stress-induced damages. To overcome these problems, here, we isolate both washed and purified DWM and compare the effects of the stress in both DWM populations. Intactness and functionality of DWM from stressed seedlings DWM were isolated from control and stressed seedlings. Since intact and coupled mitochondria are strictly required to carry out studies concerning mitochondrial metabolism, a series of experiments was performed by using both washed and purified DWM in order to ascertain structural and functional features, including the intactness of outer and inner membranes and ∆Ψ in the absence (state 1) and presence (state 4) of 5 mM succinate as oxidisable substrate. The results relative to purified DMW were already published (Trono et al., 2004), while data relative to washed DMW are reported in Table 1. Table 1. Intactness of membranes and ∆Ψ in washed DWM from control and stressed seedlings Membrane intactness (%) Control Sea water stress a Water stress Moderate % Severe % Moderate % Severe % Outer membrane 83±0.7b 68±3.3** 82 28±3.2*** 34 79±1.3* 95 67±1.5*** 81 Inner membrane 94±1.0 84±1.5*** 89 77±1.0*** 82 86±1.0** 91 83±1.5*** 88 ∆Ψ (mV) Control a Sea water stress Water stress Moderate % Severe % Moderate % ns Severe % State 4 ∆Ψ 205±3.6 194±5.2 95 187±5.2* 91 200±5.0ns 97 192±6.4ns State 1 ∆Ψ 202±3.4 140±3.8*** 69 100±3.0*** 49 170±8.0* 84 136±5.0*** 67 94 % of the control mean value ± SE (n=4) ns = not significant * P<0.05, ** P<0.01, *** P<0.001, P represents the probability level according to the Student’s t test relative to the comparison between each value with the corresponding control. b 102 A slight reduction of the membrane intactness was observed, which was more evident in sea water stress than under water stress and under severe more than under moderate stress; on the other hand, a remarkable stripping of outer membrane under severe sea water stress was observed. No important variations were observed in the ∆Ψ values in mitochondria oxidising succinate in state 4 comparing stressed and control conditions, thus confirming substantial intactness of inner membrane. Interestingly, in this set of experiments, DWM show high state 1 ∆Ψ due to endogenous substrates (Flagella et al., 2006); moreover, DWM from stressed seedlings showed lower ∆Ψ values in state 1 than control, thus suggesting progressive membrane permeability causing outflow of endogenous substrates in the course of isolation procedure as a result of increasing level of stress (Trono et al., 2004; Flagella et al., 2006). In the whole, in washed DWM, membrane intactness and ∆Ψ decreased with increasing strength stress and seawater caused more detrimental effects than parallel water stress. Comparison between the data from Trono et al. (2004) and the ones from Table 1 shows similar trends in purified and washed DWM; moreover, as expected, washed mitochondria have a lower degree of intactness than the purified ones. In any case, washed DWM from both control and stressed seedlings were obtained with a degree of functionality sufficient to explore their oxidative properties. Proline and succinate oxidation by DWM from stressed seedlings Since accumulation of free proline is known to play an important role in the cell osmotic adjustment, the effect of seawater stress and parallel water stress on proline oxidation by DWM was evaluated. In particular, by using both proline and succinate as respiratory substrates, comparison was made with respect to: (i) state 3 oxygen uptake rate (i.e. oxidation rate); (ii) coupling between oxidation and ATP synthesis (RC ratio); and (iii) phosphorylative efficiency (ADP/O ratio). Data relative to washed DWM are summarised in Table 2. Data relative to purified DWM were recently published (see Trono et al., 2004), but they are again reported between brackets in Table 2 to facilitate comparison between washed and purified DWM. Table 2. Proline- and succinate-dependent oxygen uptake rate in state 3, RC and ADP/O ratios in washed DWM under stress. The experimental conditions were as in “Materials and Methods”. Values concerning purified DWM from Trono et al. (2004) are reported between brackets. For the explanation of data reported in bold Proline-dependent O2 uptake Control Seawater stress Moderate % a vb 47±2.7 (180±10.6) 34±2.0** (91±2.4***) 72 (50) RC 1.6±0.08 (2.1±0.11) 1.2±0.01** ns (2.0±0.02 ) 75 (95) ADP/O 2.2±0.03 (2.5±0.04) 1.8±0.07** (1.9±0.08***) 82 (76) Water stress Severe % Severe % 39±1.05 (108±6.3**) 83 (60) 26±1.9*** (51±3.8***) 55 (28) 1.3±0.02* 1.0±0.03*** ndd d ns (1.0±0.03***) (nd ) (2.1±0.03 ) 81 (100) 1.0±0.01*** (1.0±0.01***) – (–) 86 (100) nd (nd) – (–) 19±1.1*** (31±1.8***) d nd d (nd ) % 40 (17) – (–) Moderate * 1.9±0.03*** (2.5±0.11ns) Succinate-dependent O2 uptake Control Sea water stress Water stress Moderate % Severe % 79 (88) 105±7.8*** (316±16.0**) 54 (62) c v 195±11.5 (510±30.0) 155±9.2* (450±15.0ns) RC 1.9±0.09 (2.3±0.10) 1.4±0.04** ns (2.3±0.04 ) ADP/O 1.8±0.03 (1.8±0.03) 1.6±0.04** ns (1.7±0.08 ) Moderate % ns 180±10.5 92 (540±31.6ns) (106) Severe % 128±7.5** (370±21.6**) 66 (72) d 1.6±0.05* 1.0±0.01*** 74 nd d (100) (1.0±0.01***) (nd ) (2.3±0.04ns) 84 (100) 1.3±0.08** (2.0±0.06*) 68 (87) 1.8±0.07ns (1.8±0.07ns) 100 (100) 1.5±0.04*** ns (1.8±0.05 ) 83 (100) 89 (94) d nd d (nd ) – (–) a % of the control -1 -1 state 3 oxygen uptake rate expressed as natom O2 ⋅ min ⋅ mg of protein c mean value ± SE (n=4) d not determinable in mitochondria having RC ratio equal to 1, i.e. uncoupled (Trono et al., 2004; Flagella et al., 2006) ns = not significant *P<0.05, ** P<0.01, *** P<0.001, P represents the probability level according to the Student’s t test relative to the comparison between each value with the corresponding control. b 103 The results of Table 2 show that both sea water stress and water stress lead to an inhibition of proline and succinate oxidation and a decrease of both coupling and phosphorylative efficiency. Consistently, we have recently reported a decrease of the rate of ATP synthesis under these conditions (Flagella et al., 2006). These results are in accordance with several literature reports (Stewart et al., 1977; Sells and Koeppe, 1981; Schmitt and Dizengremel, 1989). These effects were found to increase with increasing stress intensity; moreover, they were found to be more evident under sea water stress than under water stress, so confirming that under our experimental conditions the overall sea water damage is dependent on both a toxic and an osmotic component (Greenway and Munns, 1980). Interestingly, as previously found in water-stressed maize seedlings (Sells and Koeppe 1981) and other model systems (Boggess et al., 1978; Schmitt and Dizengremel, 1989), we show that the decline in proline oxidation rate under stress conditions was even more dramatic than for succinate. This sharp reduction leads to the hypothesis that the imposed stress conditions affect in a specific manner mitochondrial mechanisms responsible for proline oxidation. At this regard, by comparing washed and purified DWM with respect to the percentage values of Table 2 of both proline and succinate oxygen uptake rate under all stress conditions, an interesting finding is obtained: the inhibition of proline oxidation is more evident in purified than in washed DWM, while the inhibition of succinate oxidation is more marked in DWM washed fraction. In order to emphasise this finding, the percentage data reported in bold in the % columns of Table 2 are processed as shown in Fig. 1. Fig. 1. Opposite behaviour of proline and succinate oxidation by washed and purified DWM from stressed seedlings. The % data are the ones reported in bold in Table 2. The opposite effect of stresses on proline and succinate oxidation is well evident. This effect may be observed irrespective to the kind and intensity of the stress imposed. So, a more evident inhibition of succinate oxidation was observed in the washed fraction, which contains the more damaged organelles, than in the purified one, while the inhibition of proline oxidation is much higher in purified DWM, i.e. the highly intact and fully functional organelles. In the light of this, it is reasonable to suppose that the alterations found in succinate oxidation represent damages due to the stress imposed. On the contrary, the decrease in the proline oxidation rate should be considered an active mitochondrial adaptation to stress rather than a generic early damage 104 of the oxidative properties. Consistently, we have recently showed that inhibition of proline oxidation parallels proline accumulation in durum wheat seedlings (Flagella et al., 2006). Anyway, data reported in literature (Boggess et al., 1976; Voetberg and Sharp, 1991) show that the increase in the proline synthesis from glutamate rather than inhibition of oxidation represents the main factor resulting in proline accumulation in stressed plant tissues; this point will merit further investigation in durum wheat. AOX activity in DWM from stressed seedlings The AOX branches from the respiratory chain at the level of ubiquinone and it is known to be cyanide and antimycin insensitive. Since AOX bypasses the last two sites of energy conservation associated with the cytochrome pathway, it shows a non phophorylating and, as a consequence, an energy dissipating character (Vanlerberghe and McIntosh, 1997). This appears to be useful to control both ∆Ψ and mitochondrial ROS generation, which occurs at high rate when ∆Ψ is high. As a consequence, AOX is expected to act as an antioxidant system under environmental stresses inducing oxidative stress at cellular level (Maxwell et al., 1999; Pastore et al., 2001 and refs. therein). Therefore, experiments were performed to evaluate its activity under our conditions of stress imposition, that were shown to enhance mitochondrial superoxide anion generation (Trono et al., 2004). In this case, only the purified DWM were studied. AOX activity in succinate oxidising DWM was evaluated by means of oxygen uptake measurements in the presence of dithiothreitol (DTT) and pyruvate, specific AOX activators (Fig. 2a) (Millar et al., 1993; Vanlerberghe and McIntosh, 1997). Fig. 2. AOX activity expressed as a fraction of cytochrome pathway in DWM purified from control and stressed seedlings. (a) Measurements of oxygen uptake by DWM purified from moderately sea water-stressed seedlings were carried out in 1.5 mL of the medium reported in “Materials and Methods”; ATP (200 µM) was also present in order to activate succinate dehydrogenase. The compounds were added at the time indicated by the arrows. DTT and pyruvate are AOX activators. The -1 -1 numbers on the traces refer to the natom of oxygen taken up ⋅ min ⋅ mg of protein. The AOX activity was expressed as V+KCN/V-KCN, where V-KCN and V+KCN represent the rate before cyanide addition and the residual rate in the presence of cyanide plus AOX activators, respectively. (b) AOX activity under control and stress conditions. Data are expressed both as mean value ± SE (n=4) and as % of the control. ns = not significant; * P<0.05, P represents the probability level according to the Student’s t test relative to the comparison between each value and the control. 105 Oxygen uptake was started by adding 10 mM succinate to DWM suspended in the reaction medium; the measured oxygen uptake rate was indicated as V-KCN. Then, 1 mM KCN was added which completely blocked oxygen uptake, since DWM do not spontaneously show alternative respiratory pathway (Pastore et al., 2001). The addition of 1 mM DTT and 1 mM pyruvate stimulated a cyanide-insensitive oxygen uptake rate, indicated as V+KCN, which was completely stopped by 1 mM salicylhydroxamic acid (SHAM), a powerful AOX inhibitor. The V+KCN/V-KCN ratio was used as an indicator of the AOX activity, expressed as a fraction of cytochrome pathway. This assay gives useful information about maximal activity of the AOX measured in vitro, which is a parameter related to the AOX amount in DWM, but is unable to test AOX contribution to overall respiration in vivo. To do this, further studies are required based on isotope fractionation technique (Ribas-Carbo et al., 2005a). Based on measurements shown in Fig. 2a, AOX dependent oxygen uptake in control conditions was about 35% with respect to the one dependent on cytochrome pathway. The comparison between control and stress conditions shows that the contribution of AOX functioning with respect to the cytochrome pathway was unchanged under moderate stresses and even little inhibited under severe stresses (Fig. 2b). Although this result is in apparent contrast with the widely accepted role of this enzyme as a protective system under stress conditions, it is not surprising. In fact, also Kasai et al. (1998) reported that, though the alternative pathway plays a critical role in germinating wheat seedlings, NaCl salinity do not affect it. Moreover, Jolivet et al. (1990) found that in barley the activity of the alternative pathway under NaCl stress was not modified in isolated mitochondria, while it was increased in whole leaf tissue. Finally, Lutts et al. (2004) found an increase in the relative importance of AOX in durum wheat callus submitted to NaCl stress, but this was lower in salt resistant cultivars than in salt sensitive ones; so, it seems that the stimulation of the alternative pathway may be not necessarily related to stress resistance. As far as durum wheat is concerned, our previous findings strongly suggest that AOX may act as an antioxidant defence system not in etiolated tissues, but in green tissues, that may contain hydroxypyruvate and glyoxylate, two powerful DWM-AOX activators (Pastore et al., 2001). Consistently, Ribas-Carbo et al. (2005b) recently reported that in soybean leaves severe water stress caused a significant shift of electrons from the cytochrome to the alternative pathway due to a biochemical regulation other than protein synthesis. As for etiolated tissues, DWM display high activity of two different dissipating systems able to dampen mitochondrial ROS production, namely the PUCP (Pastore et al., 2000) and the PmitoKATP (Pastore et al., 1999a). Moreover, we have recently shown that PUCP and PmitoKATP are strongly activated in DWM under salt and water stress in order to act against oxidative stress (Trono et al., 2004), thus replacing AOX function. Our idea of a tissue specific cross-regulation between PUCP, PmitoKATP and AOX is consistent with the finding of Sluse et al. (1998) who reported opposite regulation by free fatty acids of PUCP and AOX, and with our observation that both PmitoKATP and PUCP are directly and very rapidly activated by ROS (Pastore et al., 1999a; Pastore et al., 2000), while this does not occur in the case of AOX (Pastore et al., 2001). For a very recent review about this topic see Pastore et al. (2007). CONCLUSIONS Durum wheat resistance to salt and water stress may be a function not only of proper morphophysiological adaptations, but also of biochemical characteristics including mitochondria metabolism. Here, we suggest that early inhibition of proline oxidation under stress may be a useful character to improve salt and water stress tolerance; instead, the role of AOX against these stresses is questionable in durum wheat. 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Role of increased proline deposition in osmotic adjustment. Plant Physiol., 96: 1125-1130. 108 SUBMERGED REVERSE OSMOSIS PLANT (SROP) D. N. Bapat – 15.10.2006 The Tata Power Company Ltd 34, Sant Tukaram Road, Carnac, Mumbai 400 009, INDIA SUMMARY – The availability of Potable water on the land is depended on the natural cycle of evaporation, condensation and precipitation of sea water. This is dependent on various factors and in large areas there is scarcity of potable water. In this article a Submerged Reverse Osmosis Plant is described which has been worked out that provides a cheap source of potable water from sea water. Due to development of Reverse Osmosis membranes that can filter out salt molecules it is possible to have potable water from sea water. However, this process requires high pressure sea water. In this plant the high pressure sea water is derived from deep sea that makes the potable water cheap. An innovative mechanism is used to develop the high pressure sea water. The scaled model is under construction and working plant is planned in near future. Key words: Potable water, Reverse Osmosis INTRODUCTION The potable water availability on the land is diminishing. Efforts are made to convert abundant sea water into potable water for drinking & industrial use. To obtain potable water from Sea water Reverse Osmosis (RO) is one of the processes that has been used and proven to be an economical and environmental friendly process as it consumes lower energy per cubic meter of potable water produced as compared to other process like distillation etc. However, in RO of Sea Water (SW) major part of the energy is consumed in following activities: • In bringing sea water to the RO Plant on the shore by pumping: Large quantity of SW has to be pumped from depth of sea to long distance (4-10 km) to the RO Plant on the suitable coastal site. As the RO efficiency decreases a lot with the increase in concentration of salt in the SW, th only about 1/10 volume of potable water can be produced from a volume of sea water. That is to say about 1000 liters of SW has to be used to produce 100 liters of potable water. This requires large quantity of SW to be pumped and transported to the RO plant. • In maintaining high pressure of SW across the RO membrane: Pumps have to run continuously to maintain high pressure of the order of 60 to 70 bar of SW across the RO membrane. This is a large energy consuming process involved in RO plants. • The capital cost and running cost of RO plants is due to the following: i) Large length of piping and pumping system required for pumping SW to RO plant at shore. ii) High pressure pump sets to maintain high pressure SW as described above. iii) Land cost of the area occupied by RO plant. iv) Operation and maintenance cost of RO plant as high pressures are involved. 109 In the SROP the above referred costs are eliminated/ reduced so that the cost of potable water produced is lesser than the cost of potable water produced by conventional RO plant as explained below: • The SROP is submerged in the sea below a level of about 60 meters. This allows availability of SW in abundance to the SROP eliminating the cost of transporting sea water to RO plant. • The high pressure SW required for RO process is developed with the help of an innovative mechanism from the pressure of the sea at the depth of sea. This eliminates high pressure pumping system required to maintain high pressure across RO membrane. • Only a small pump is required to fetch potable water from SROP to the shore or to the point of use. Since, the amount of potable water is much less than the sea water used to produce it, the piping and pump requirements are reduced to only 10%. • The land requirement on shore is totally eliminated, since SROP does not require any land for installation being installed submerged in sea. • The SROP is designed to operate in fully automatic mode that eliminates operation cost to large extent. • The components and mechanism of SROP have been designed to be with minimum requirements for maintenance. Also, the material of construction of the plant has been selected to give protection from corrosion of sea water with minimum cost. CONCEPT AND WORKING The high pressure SW required for RO process would be at a depth of 600 to 700 meters. To locate a sea shores near which such depths of sea is available would be difficult and limited to only few places. Also such depths (600 to 700 m) of sea would be far away from sea shore. However, if the RO plant is located just 60 to 70 meters below sea level the quality of SW required for RO would be suitable and such depth of sea would be available near most of the sea shores. But at this depth the pressure of SW will not be enough for RO process. Therefore, to enhance SW pressure to the required level of 60 to 70 bar an innovative mechanism consisting of levers, pistons and cylinders in used. Please refer to the schematic of SROP attached herewith. In the pressure developing cylinder a piston is moving which is connected to Force multiplying lever. On one side of the piston, the side facing the cylinder atmospheric pressure is acting since a pipe above the sea level vents this side of the cylinder. On the other side of the piston the sea water pressure of depth of 60 meters is acting. This creates a force equal to difference of these pressures multiplied by the area of the piston and makes it to move inside the cylinder. This force is levered 10 times to act on the high pressure exerting piston in the pressure chamber A. which in turn acts on the sea water in the chamber. Thus the pressure developed in the chamber would be 10 times the pressure of SW at depth of 60 meters. The high pressure SW in the chamber A passes through RO membrane till an impasse th concentration is reached i.e. about 1/10 volume of Chamber A. The passed SW through RO membrane is free of salt and other suspended particles and is potable for use, which collects in the potable water chamber. From here it is pumped above sea level and taken to the point of use on the shore. th After the high pressure exerting piston has moved by 1/10 of its stroke the outlet solenoid valve is opened that allows the balance concentrated SW to go out to the surface of sea during the remaining stroke of high pressure exerting piston. The concentrated SW at sea level is collected for making salt. When the high pressure exerting cylinder makes full stroke, the outlet solenoid valve is closed and pump for SW is started. This pumps in fresh SW in high pressure chamber A till the piston reaches 110 fully outward and the pump is stopped closing solenoid inlet valve. At this position the above cycle repeats. The cycle is controlled by position switches and is fully automatic. PROBLEMS AND SOLUTIONS The problems envisaged in SROP are as under and their solutions are also arrived at as explained below. i) Filtration/ pre treatment of feed Water: At a depth in sea to provide filtration/ pre treatment of feed water appeared to be a problem. But using the similar arrangement as described for RO the sea water can be filtered and the filtered water is fed to inlet of pump for SW which pumps in filtered SW into the high pressure chamber A for RO. ii) Enhancement of SW pressure to required level for RO: the innovative piston solves this problem, cylinder and lever mechanism described earlier. iii) To maintain low pressure on the filtered side of RO membrane: A vent to the atmosphere is provided from the filtered side of RO membrane by this low pressure is maintained. Also this vent acts as air inlet when the potable water is pumped out to the sea level. iv) Pumping of potable water above sea level: With the suitable small submersible pump of capacity 1 cu.m/hr the potable water is pumped above sea level to be collected there for transporting to the point of use. v) Replenishment of SW in the pressurized RO chamber is achieved by a high pressure submersible pump that has a capacity about 1 cu.m/Min and can stand the sea water environment around at 60-70 bar pressure. This pump would be working only one minutes in every 6 minutes. vi) Maintenance of SROP under deep sea water: The platform on which SROP is mounted is placed on the sea bed about 60 meters below sea level. For periodic maintenance once in 6 months or as per need it can be pulled up above sea level from floating Barges and placed on them for maintenance and component replacement. After maintenance it can be lowered and placed back in position. vii) Corrosion due to SW at higher pressure: Stainless steel of suitable quality is used for structural and load carrying members and cylinders etc. The pistons are fabricated out of non corrosive material with piston rings made out of Teflon that gives protection against corrosive atmosphere. The material of pressure pump is also selected that avoids its corrosion. SCHEMATIC OF SRPO The schematic of SRPO is enclosed as Annexure. The working of the SRPO is explained above. The brief bill of material for SRPO is as under: • • • • • • • • • • Mounting platform Prefilter vessel Pressure developing cylinder Link L1 Pressure developing piston Force multiplying lever Pump for Potable Water Piping for inter connection and vents etc Limit Switches Solenoid Valve/ NRV • • • • • • • • • • • Outlet Solenoid Valve Contactors Cables/ bushing Sealant Fulcrum/ Pivot Link L2 High Pressure Chamber A High pressure exerting piston RO Membrane with mounting arrangement Potable water chamber Pump for Sea Water Power supply 111 PROJECT IMPLEMENTATION The detailed design of SROP has been made. The design has been checked with calculations for technical feasibility. Component drawings and assembly drawings have been completed. A scaled model is under preparation. After trials on the model the drawings will be modified for production of SROP. Few sites along the Western Coast of India where depth of sea is adequate and the quality of water is suitable have been identified. Permissions from authorities to conduct the trials of SROP have been initiated. Efforts are made to find the funding agency for the project and further communication is in progress with them. COST ESTIMATES The cost for making model and its trials are estimated at Rs.0.5 million (US $ 11 thousand). The estimated capital cost of SROP of 1 Cu.M /hr capacity is Rs.2.00 million (US $ 44 thousand) at present level of prices. The cost of 1 Cu.M of potable water produced by the plant works out to be Rs.27 (US $ 0.6) The cost estimates are being revised on receiving the quotations for components and material which are being obtained at present. PLAN To complete the model its trials, manufacturing SROP and its commissioning, it is estimated to take two years. Low cost funding is sought from World Bank and other eco friendly institutes, which will speed up the activities and make it economical. There are some innovative processes in SROP for which actions for IPR have been initiated. The plan for commercialization of SROP has been made. The commercial version of SRPO will be a boon for settlements, installation, projects on sea shore and in the sea where potable water is needed by the mankind. 112 113 TREATED WASTEWATER SOURCES: ACTIONS TOWARDS SUSTAINABLE AND SAFELY USE IN THE NEAR EAST AND ACHIEVING FOOD SECURITY IN WATER-SCARCE POOR RURAL COMMUNITIES R. Choukr-Allah Head of the salinity and plant nutrition laboratory I.A.V Hassan II Agadir, Morocco BP 773 E-mail: [email protected] or [email protected] SUMMARY- Near East and North Africa countries (NENA) are characterized by severe water imbalance uneven rainfall, and at the same time, are unable to meet their food requirements using the available water resources. Treated and re-used sewage water is becoming a common source for additional water. Some of these countries have included wastewater re-use in their water planning. This will narrow the gap between freshwater supply and demand in different water-use sector. Wastewater recycling and reuse have become increasingly important for two reasons in the NENA region. Firstly, properly treated municipal wastewater often is a significant water resource rich in nutrients for crop production. Secondly, discharge of sewage effluent into surface effluent into surface water is becoming increasingly difficult and expensive as treatment requirements become more stringent to protect receiving waters such as rivers, estuaries, and beaches. In small communities, the quality of the effluent from wastewater treatment plants (WWTP) is limited by the low feasibility of investment in construction of small-scale WWT facilities and in their operation. Using the treated effluent for irrigation purposes adds an economical driving force for investments in WWT. Another economic advantage of choosing agricultural irrigation, as a final disposal solution for the treated effluent is that it permits low quality demands, especially in regard to nutrients removal. Final disposal by irrigation is usually combined with non-compromising hygienic demands. Controlled utilization of the treated effluent reduces the environmental risks of polluting lakes, rivers and/or other land and water resources, which might be caused by other alternatives of effluent disposal. Governments in NENA should assess the reuse of treated wastewater with an integrated approach taking into account not only the monetary cost and benefits in terms of ecological, social and economic concerns, but more to consider a systemic perspective of the sustainability impacts. Moreover such a systemic perspective should be developed in a participatory process with a specific focus on the local or regional conditions. Furthermore the acceptance for the reuse and the costs of treating the wastewater and transporting it to the reuse location should be taken into account and handled appropriately. This paper will address the integrated approach for reclamation and reuse of treated wastewater? The criteria and standard that should be applied for wastewater reuse in agriculture? What are the appropriate treatment technologies to be used for poor rural areas? What are the viable options for reuse of waste water, what are the most salient constraints (both technically, institutionally and financially), and how can we move forward with the use of treated waste water for agriculture within the parameters of rural development in the NENA region, including sustainability issues? INTRODUCTION Near East and North Africa countries (NENA) are characterized by severe water imbalance uneven rainfall, and at the same time, increased demands for irrigation and domestic water supply have been occurred in recent last two decades as a result of expending urban population and tourist industry. . This region is the driest on earth, containing only 1% of the world’s freshwater resources and will become water-stressed because of increased water scarcity (Seckler et al., 1998; FAO, 2003) (Table 1). Although water is recycled in the global hydrologic cycle for millenniums; much smallerscale planned local water recycling and reuse have become increasingly important for two reasons in the NENA regions. 115 Evaluating the challenges and opportunities for using marginal-quality waters will help in guiding investment and management decisions pertaining to land and water management in agriculture. Considering the growing water shortage in the Near East and North Africa countries and history of water use, it is expected that the use of marginal-quality waters for various purposes will be more common in the foreseeable future. Key decisions are needed in the short and long terms in relation to the use of such water resources to support achievements of the United Nations’ Millennium Development Goals to enhance food security and environmental quality during the next 50 years. In addition, there is a need to address the current situations where marginal- quality waters are already used for food production especially in resource-poor environments, where regulations need to be realistic and feasible Agriculture reuse of treated wastewater should be integrated into comprehensive land and water management strategy taking into count water supply, type of treatment technology, final reuse, social and economic context. The reuse of treated waste water enhance agriculture productivity in several NENA countries, however it will require public health protection, appropriate treatment technology, public acceptance and participation. This paper assesses the current situation regarding the use and significance of wastewaters in agriculture and also provides insight into the technological, institutional, and policy options that might help in increasing its advantages and opportunities while reducing possible negative impacts on people and the environment. Table 1. Estimates of populations and natural renewable water resources (NRWR) per capita in selected NENA countries during the year 2002 and projections for the year 2025. Country Kuwait United Arab Emirates Qatar Libya Saudi Arabia Jordan Bahrain Yemen Israel Oman Algeria Tunisia Egypt Morocco Lebanon Syria 3 Population (× 10 ) NRWR (m3 capita–1 yr–1)b 2002 2025c 2002 2025d 2023 2701 584 5529 21701 5196 663 19912 6303 2709 31403 9670 70278 30988 3614 17040 3219 3468 754 7972 40473 8666 887 48206 8486 5411 42738 12343 94777 42002 4581 27410 10 56 91 109 111 169 175 206 265 364 460 577 830 936 1220 1541 6 43 70 75 59 102 131 85 197 182 338 452 615 691 962 958 Source: Qadir and al 2006. (based on databases of the AQUASTAT Information System of Food and Agriculture Organization of the United Nations, the World Bank, and the World Resources Institute; a modified from World Resources Institute, 2003) a Selected countries from West Asia and North Africa and Sub Saharan Africa. NRWR include Internal Renewable Water Resources plus or minus the flows of surface and groundwater entering or leaving the country, respectively. c UN medium variant population projections for the year 2025. d Based on the assumption that the NRWR in the countries in 2025 will remain the same as in 2002. b POTENTIAL OF TREATED WASTEWATERS The volume of wastewater increases with increasing population, urbanization, and improved living conditions (Raschid-Sally et al., 2005). Considering 20% as the depleted fraction from urban water use and anticipating growth in urban water supply coverage as a proxy for amounts of wastewater generated, it is revealed that in spite of reliance on onsite sanitation, wastewater from Near East and 116 North Africa cities will pollute large volumes of water for the downstream agriculture (Scott et al, 2004). In most developing countries, urban drainage and disposal systems are such that wastewater generated by different activities gets mixed and the resulting effluent may be disposed of in a wastewater treatment plant, in another water body, or diverted to farmers’ fields in treated, partly treated, diluted and/or untreated form (Qadir et al.2006). Table 2. Volume of wastewater generated annually in some NENA countries ___________________________________________________________________________ 6 3 –1 Country Reporting year Wastewater volume (× 10 m yr ) ___________________________________________________________________________ Algeria 2004 600 Bahrain 1990 45 Egypt 1998 10012 Jordan 2004 76 Kuwait 1994 119 Lebanon 1990 165 Libya 1999 546 Morocco 2002 650 Oman 2000 78 Saudi Arabia 2000 730 Syria 2002 825 Tunisia 2001 240 Turkey 1995 2400 United Arab Emirates 2000 881 Yemen 2000 74 ___________________________________________________________________________ Source: (Aquastat, FAO, 1997, Qadir and al. 2006) WASTEWATER AS ADDITIONAL WATER RESOURCE There are several benefits of treated wastewater reuse. First, it preserves the high quality, expensive fresh water for the highest value purposes–primarily for drinking. The cost of secondarylevel treatment for domestic wastewater in NENA, an average of $US 0.2 to 0.5/m3, is the cheaper, in most cases much cheaper, than developing new supplies in the region (WB, 2000). Second, collecting and treating wastewater protects existing sources of valuable fresh water, the environment in general, and public health. In fact, wastewater treatment and reuse (WWTR), not only protects valuable fresh water resources, but it can supplement them, through aquifer recharge. If the true, enormous, benefits of environmental and public health protection were correctly factored into economic analyses, wastewater collection, treatment and reuse would be one of the highest priorities for scarce public and development funds. Third, if managed properly, treated wastewater can sometimes be a superior source for agriculture, than some fresh water sources. It is a constant water source, and nitrogen and phosphorus in the wastewater may result in higher yields than freshwater irrigation, without additional fertilizer application (Papadopoulos, 2000). Research projects in Tunisia have demonstrated that treated effluent had superior non-microbiological chemical characteristics than groundwater, for irrigation. Mainly, the treated wastewater has lower salinity levels (WB, 2000, pg.8). Estimates of the extent to which wastewater is used for agriculture worldwide reveal that at least 6 2 × 10 ha are irrigated with treated, diluted, partly treated or untreated wastewater (Jimenez and Asano, 2004). The use of untreated wastewater is intense in areas where there is no or little access to other sources of irrigation water and is being practiced in several North African countries. 117 Table 3. Annual domestic and industrial water use and potential treated wastewater for reuse in some NENA countries. Total Potential Irrigation Savings M m3/year Domestic Savings Potential industrial/Commerci al Savings Potential M m3/year M m3/year Treated Wastewater Potential for use M m3/year Water Savings l Potential M m3/year Syria 1,360.0 174.1 3.5 135.9 1,673.5 Lebanon 95.0 99.7 1.9 286.3 482.9 Jordan 73.8 71.0 0.4 89.7 234.9 Egypt 4,773.0 1,079.4 55.5 5,108.1 11,016.0 Libya 400.2 161.9 1.2 248.0 811.2 Tunisia 270.6 91..5 1.2 201.1 564.3 Algeria 270.0 368.3 8.4 1,138.6 1,785.4 Morocco 1,016.1 186.5 4.1 553.9 1,760.6 Turkey 2591.5 1,818.8 48.8 6,173.9 10,633.0 Total 16,976 10,250 781 65,968 93,974 WASTEWATER REUSE IN THE NEAR EAST AND NORTH AFRICAN COUNTRY Countries in the region which practice wastewater treatment and reuse include Jordan; Lebanon, Tunisia, Israel, Kuwait, Emirates, Saudi Arabia, and Egypt (Choukr-Allah and Hamdy 2004). However, only Tunisia, and to a certain extent, Jordan, already practice wastewater treatment and reuse as an integral component of their water management and environmental protection strategies. In Tunisia, treated effluent with a total flow 250 m3/day is used to irrigate about 4500 ha of orchards (citrus, grapes, olives, peaches, pears, apples, and pomegranate), fodder, cotton, cereals, golf courses and lawns (Abu-Zeid, 1998). The agricultural sector is the main user of treated wastewater. Mobilisation of treated wastewater, and transfer or discharge is an integral part of the national hydraulic equipment program and is the responsibility of the State, like all related projects. The advantage of this water resource is that it is always available and can meet pressing needs for irrigation water. Indeed use of wastewater saved citrus fruit when the resources dried up (overexploited groundwater) in the regions of Soukra (600 inhabitants) and Oued Souhil (360 inhabitants) since 1960 and contributed among other things to the improvement of strategic crop production (fodder and cereals) in new areas. Technical and economic criteria enabled the irrigation of more than 6600 ha mobilising 30% of discharged effluent. The average effective utilisation rate of treated wastewater is 20%. The volume consumed differs greatly from one area to another, according to climatic conditions (11 to 21 Million 3 m per year.) At present, treated wastewater is an available source of water for farmers, but on the one hand, it is not suitable for crops that are economically profitable, and on the other hand it poses some health risks. The best levels of utilisation are found in fruit crops areas, in areas with a tradition of irrigation and in semi arid areas. 3 With a projected volume of 215 million m by the year 2006, the utilisation potential of this water will be about 20,000 hectares, which is 5% of the areas that can be irrigated, if we assume intensive inter-seasonal storage and a massive introduction of water saving systems that would increase the mobilisation rate to 45%. It is expected that additional treatment of treated wastewater will improve the rate of use in irrigated areas (ONAS 2001). 118 Agricultural reuse however will not see marked improvement, unless restrictions are lifted on pilot wastewater treatment plants with complementary treatment processes. This can only be decided when the stations are functioning with acceptable reliability. This will take a few years of experience. Nonetheless, in all cases, and regardless of the treatment method, technical and organizational measures should be introduced in order to systematically warn those managing the reuse of any breakdowns that may occur in the wastewater treatment plants and to avoid the flow of treated wastewater into the distribution network. In Jordan, Treated wastewater generated at nineteen existing wastewater treatment plants is an important water resources component. About 72 MCM per year (2000) of treated wastewater are effectively discharged into the watercourses or used for irrigation, 76% is generated from the biggest waste stabilization pond Al-Samra treatment plant serving a population of 2 million (approximately 70% the total served population) in 2000. By the year 2020, when the population is projected to be about 9.9 million, about 240 MCM per year of wastewater are expected to be generated. All of the treated wastewater collected from the As-Samra wastewater treated plant is blended with fresh water from the King Talal reservoir and used for unrestricted irrigation downstream in the Jordan Valley. In Kuwait, the Government strategy for implementation of the Effluent Utilization Project was to give the highest priority to development of irrigated agriculture by intensive cultivation in enclosed farm complexes, together with environmental forestry in large areas of low-density, low water-demand tree plantations. , the Ministry of Public Works initiated the preparation of a Master Plan for effective use of all treated effluent in Kuwait, covering the period up to the year 2010 (Cobham and Johnson 1988). The overall plan recommendations for the western and northern sites (Jahra and Ardiyah effluents, respectively) it was suggested that the first priority should be devoted to developing an integrated system of forage (used in a high concentrate ration dairy enterprise) and extensive vegetable production on the UAPC (the United Agricultural Production Company) farm, so that full utilization would be made of existing and potential facilities as soon as possible. The ultimate project design provides for the development of 2700 ha of intensive agriculture and 9000 ha of environmental forestry (Agriculture Affairs and Fish Resources Authority, Kuwait 1988). Saudi Arabia is currently reusing about 20 percent of its treated wastewater in refineries, for flushing the toilets and for irrigating forage and landscape crops. In Morocco, the reuse of raw wastewaters has become a current and old practice. They are reused in agriculture in several parts the country. These practices are mainly localized to the periphery of some big continental cities where agricultural lands are located in the downstream of effluent discharge, and also in small parts around the wastes of the treatment networks. The climatic constraints had pushed farmers to irrigate their crops with raw wastewater when water resources are not available. During the last years, the reuse of wastewaters has also developed around some suburbs recently provided with a treatment network. A total of 7000 ha is directly irrigated with raw wastewaters 3 discharged by towns, i.e. about 70 million m of wastewater is used every year in agriculture with no application of the sanitary precaution (HWO standards for example). This second use concerns a diversity of cultivation types (fodder, cereals, fruit threes…). The irrigation of vegetable crops with raw wastewaters is forbidden in Morocco, but this banning is not respected, which makes the consumer of agricultural products and the farmer face risks of bacteria or parasite contaminations. In general, the volume of wastewaters that have been recycled does not represent more than 0.5% of the water used in Agriculture. This situation tends to be generalized in all the suburbs that are provided with a treatment system where wastewaters are discharged. Following an investigation carried out within the framework of NSLC (1998), a total of 70 areas using wastewaters are spread out in the territory. This practice is not free of dangerous consequences on human health and on environment. For example: 1- Spread of water diseases (more than 4000 cases of Typhoid and more than 200 case of malaria have been noted in 1994, some cholera sources in the Sebou basin). 2- Difficulty and high cost in processing potable water. 119 3- Many section of water courses in the country present a largely weak quantity of dissolved oxygen, and even a deficit in oxygen when these discharges are important, which causes massive fish mortality, and; 4- Many dam volumes present marks of eutrophication, as a consequence of the important phosphor and nitrogen wastes. Since early nineties, many multidisciplinary projects concerning the treatment and reuse of wastewater in irrigation have been launched in Morocco. The aim was to answer the major agronomic, health, and environmental concerns. The results of these researches have made the local collectivities and the regional agriculture services benefit from reliable data necessary to conceive and to size the treatment plants of wastewaters adapted to the local contexts and to disseminate the best practices for reusing treated wastewaters in agriculture. In Egypt an ambitious programme is running for municipal wastewater treatment that will provide 3 by the year 2010 nearly 3 billions m /yr of treated wastewater as an additional water source to be used in agriculture (Abu-Zeid, 1992). WASTEWATER TREATEMENT TECHNOLOGY The rural sector the entire Near East and North Africa has suffered from much neglect as far as its sewage, wastewater treatment and wastewater reuse. The problem has become more acute in recent years due to the sharp increase in the domestic water demand, due to the continued water shortage and due to the strive to raise standard of living. Falling behind in the wastewater management and reuse caused raw sewage to flow in the public roads, thus causing contamination of ground water, local wells and drinking waters, creation of nuisances and danger of public health with frequent outbreaks of water-borne diseases. Unauthorized irrigation was the main source of cholera outbreaks in NENA countries with many hospitalized people and many fatalities. Such outbreaks also caused a severe reduction in the tourism to some countries and may have affected the tourist industry in these countries for several years. Rural area communities in Near-East and North African countries have several features in common that guide the design and operation of wastewater treatment plants, as follows: 1. Need for wastewater reuse for irrigation during the long dry summer months and the need for seasonal storage of wastewater from winter to summer. 2. Usually enough inexpensive land area around and adjacent to the community is available. 3. Sunlight is usually abundant in these regions, giving advantage to photosynthetic and other solarenergy-dependent processes. 4. Relatively concentrated wastewater due to limited per-capita water consumption rate. 5. Relatively high pathogenicity of the wastewater due to endemicity of certain diseases and high proportions of carriers. 6. Shortage of capital investment. 7. Absence, shortage or unreliability of electrical power. 8. Need for minimal, simple and inexpensive operation and maintenance of facilities. Using the treated effluent for agricultural irrigation can increase the motivation for investments in wastewater treatment plants. This will add an economical value force both for increasing capital investments and the expenses needed for proper operation and maintenance of the wastewater treatment facilities. Effluent quality aspects are also influenced by the decision to use the effluent for irrigation, since the demand for high removal efficiency of pollutants like nitrogen and phosphorous does not exist, while the treatment technology should be directed for high hygienic demands. By using the effluent for controlled irrigation much of the environmental risks caused by other effluent disposal alternatives (e.g. disposal to rivers, lakes, sea etc.) are prevented, so it is obvious that both the farmers and the environment can be benefited from effluent reuse in small communities. The selection of technologies should be environmentally sustainable, appropriate to the local conditions, acceptable to the users, and affordable to those who have to pay for them. In developing countries, western technology can be a more expensive and less reliable way to control pollution from 120 human domestic and industrial wastes. Simple solutions that are easily replicated, that allow further up-grading with subsequent development and that can be operated and maintained by the local community are often considered the most appropriate and cost effective. The choice of a technology will depend to the type of reuse. The selection of reuse option should be made on a rational basis. Reclaimed water is a valuable but a limited water resource; so investment costs should be proportional to the value of the resource. Also, reuse site must be located as close as possible to the wastewater treatment and storage facilities. Indeed, the selection of the best available technology is not an easy process: it requires comparative technical assessment of the different treatment processes, which have been recently and successfully applied for prolonged periods of time, at full scale. However, this is not sufficient, the selection should be carried out in view of well-established criteria comprising: average, or typical efficiency and performance of the technology; reliability of the technology; institutional manageability, financial sustainability; application in re-use scheme and regulation determinants. Furthermore, for technology selection, other parameters have to be carefully considered: wastewater characteristics, the treatment objectives as translated into desired effluent quality which is mainly related to the expected use of the receiving water-bodies. Presently there are a limited number of appropriate treatment processes for small communities, which should be considered. These include stabilization ponds or lagoons, slow sand filters, land treatment systems, and constructed wetlands. All of these fit the operability criteria discussed above, and to varying degrees, are affordable to build and reliable in their treatment performance. In order to illustrate the viability of these systems, the following example is provided. In this example, a small sewered community collects its wastewater at the treatment site, and the effluent will be required to meet WHO standards for unrestricted agricultural irrigation. If a pond system were chosen, WHO offers a waiver from the criteria. However, many researchers have found a high variability in their capability to consistently meet WHO microbiological criteria. Therefore, the designer may wish to supplement the ponds with a tertiary system to meet the criteria consistently. Appropriate stabilization pond upgrading methods to meet WHO reuse standards include free-water-surface (FWS) constructed wetlands, which can provide both the detention time of required maturation ponds of the same size and removal of algae from the pond effluent which can clog some irrigation systems; intermittent sand filters, which remove the parasite eggs and faecal coliforms, and slow-rate infiltration (SRI) and rapid infiltration (RI) systems. The latter two systems, however, transport their purified effluent to the groundwater, where it normally must be pumped back to the surface for irrigation use. A stabilization pond system can also be upgraded by a floating aquatic plant system in the same manner as the FWS constructed wetland. Such a system will, however, significantly increase operational requirements. Intermittent sand filters (ISF) are capable of meeting the parasite and faecal coliforms criteria, but the recirculating sand filters (RSF) have not yet been shown to do so. The latter are more compact and capable of significant nitrogen removal, but require mechanical equipment in the form of pumps. Subsurface soil infiltration (SWIS), slow rate infiltration (SRI) and rapid infiltration (RI) systems can also meet the criteria, but will require pumping energy, since all three transport their effluents to the groundwater. A listing of potential cost effective alternatives which accomplish the example treatment task by providing reusable water at the surface without the need for electrical equipment are: 1. Stabilization ponds + FWS constructed wetland 2. Anaerobic (high rate) ponds + ISF 3. Imhoff tanks + ISF Analysis of the above appropriate treatment technology systems in greater depth can assist future designers of small community wastewater systems to understand some of the tradeoffs and areas of uncertainty. Among the issues, which may sway the choice of treatment systems are performance, reliability, area requirements, capital and construction costs, and socio-economic issues. Area requirements for these systems to treat 100 m3/d of wastewater are estimated and reported in Table 4. 121 Table 4. Area required for the three systems. System Stabilization ponds + FWS constructed wetland Anaerobic (high rate) ponds + ISF Imhoff tanks + ISF 2 Area Required (m ) 13,300 1,950 1,850 Both filter based systems require only a small fraction (about 15%) of the area required for the pond/constructed wetland system. Even if one were to accept the conclusion that a series of ponds can meet unrestricted irrigation standards, the area requirement is still about 7-times that required by the ISF systems. In terms of performance or removal of pollutants the two options can only be compared when the ultimate use of the effluent is known, thus providing a specific need. In the case of irrigation reuse this involves the crop(s) to be irrigated, the aquifer characteristics below the crop, the soil, the method of irrigation and the irrigation water demand pattern. Each type of crop has different tolerances for certain pollutants, specific patterns for nutrient demand and limitations, and different patterns of demand for irrigation water. Unconfined aquifers of limited capacity will be much more sensitive to irrigation water constituents which escape the root zone and are flushed to the aquifer surface, than would be a confined aquifer or one of greater volume. Similarly, certain soils are more capable of removing dissolved constituents than others due to their physical and chemical characteristics and prior history of use. Also, the microbiological requirements for subsurface drip irrigation are far less severe than surface distribution methods. Traditional criteria used for pond design are not normally of great importance in water-short areas like North Africa, since ponds are designed for BOD removal, not faecal coliforms or parasitic egg removal, the removals of faecal coliforms and nematode eggs control the design. Only when a wastewater with a very high BOD (800 mg/l or more) should BOD removal model be considered. Since the removal of pathogens is a time-related relationship, substitution of a FWS constructed wetland for some of the maturation-pond time required in the lagoon system should be feasible, however no studies have yet determined exactly what the equivalency ratio is. To meet WHO standards the total required retention times for a typical stabilization pond-treated influent to meet WHO standards, and for different parameters at 20°C are reported in Table 5. Table 5. Required retention times for different parameters regarding WHO standards Parameter BOD, mg/l Fecal Coli, per 100 ml Nematode Eggs, per liter Days 5 16 18 Reference Reed and Middle brooks. 1995 Marais, GVR. 1970 Ayres, and al. 1992 In summarizing the options for a small community the choice of treatment for ultimate reuse will hinge on the following: - Reuse Requirements - If the reused wastewater is to be used for vegetables, citrus or other crops to be eaten raw, the options employing stabilization ponds and intermittent filters can be used, or a recirculating filter may be substituted with subsurface drip irrigation only. This last restriction may be lifted if it can be proven that the RSF effluent is free of nematode eggs, or if disinfection of the effluent is employed. - Land Availability - If sufficient land is available the other limitations stated above and below will control the options evaluated. If land availability is limited by economics or terrain or surrounding development, one of the filter options should be chosen. - Operational Capability - If a sufficiently skilled management program with electricity is available, all options are possible. If, as is often the case, only unskilled labour is locally available, only the pond-wetland or anaerobic lagoon-intermittent filter options are viable. 122 Table 6. Comparison of the two passive alternative technologies Lagoon-Wetland Land requirement, m2 Energy KWH/d Capital cost, US$ O&M cost, US$/yr. Effluent Quality BOD5 (in=200), mg/l TSS (in=100), mg/l TN (in=50), mg/l TP (in=10), mg/l FC (in=106), per 100 ml Virus (in=103), per L Parasite Ova (in=103), per L 13,000 0 200,000 250,000 5,000-7,000 10 10 10-35 7-8 102-103 101-102 0-10 Anaerobic Lagoon-ISF 2,000 0 150,000 200,000 7,000-10,000 5 5 35-40 7-9 101-102 0-10 0 Finally, when the viable options which pass the above tests are evaluated against each other, experience in the Morocco has shown that they are very similar in present worth cost, so local availability or cost of components, climatic and social conditions, and support infrastructure may be the deciding factor between them. For example, the lack of suitable sand or substitute media locally will significantly increase the cost of the filter options. Very close proximity of housing to the treatment site may make odour concerns a key issue, and add costs to certain options to control odours. Therefore, engineering decisions of which method of treatment or sitting of the facility may be skewed to suit local needs. However, in all cases the appropriate technology options presented herein are significantly more sustainable than the use of sophisticated urban wastewater treatment technologies such as activated sludge with tertiary treatment for small communities of NENA region. CONSTRAINTS OF THE REUSE Bearing in mind that treated wastewater could be used for agricultural purposes, it is important to realize that such wastewater must be adequately treated and used appropriately. The main constraints of using treated wastewaters are related to health issues, the absence of effective wastewater standards, the of law enforcement, lack of awareness and scarcity of funds. Wastewater quality and health issues Irrigating with untreated wastewater poses serious public health risks, as sewage is a major source of excreted pathogens - the bacteria, viruses, protozoa- and the helminths (worms) that cause gastrointestinal infections in human beings (Blumentha and al 2000). Unregulated and continuous irrigation with sewage water may also lead to problems such as soil structure deterioration (soil clogging), salinization and phytotoxicity. The ideal solution is to ensure full treatment of the wastewater to meet WHO guidelines prior to use, even though the appropriateness of these guidelines are still under discussion. However, in practice most rural villages in NENA countries are not able to treat their wastewater, due to low financial, technical and/or managerial capacity. In many rural areas a large part of the wastewater is disposed of untreated to rivers and cesspools, with all related environmental consequences and health risks. The perspectives regarding treatment of their wastewater are bleak. It may safely be assumed that the farmers increasingly will use wastewater for irrigation, irrespective of the national regulations and quality standards for irrigation water. In any case, usually, sewage treatment plants rarely operate satisfactorily and, in most cases, wastewater discharges exceed legal and/or hygienically acceptable maxima. This does not necessarily lie in the treatment plants themselves, but in the frequent lack of adequately trained technicians capable of technically operating such treatment plants. 123 The discharge of untreated wastewater and/or minimally treated in water sources has resulted in a substantial economic damage and has posed serious health hazards to the inhabitants, particularly in the low income NENA countries. This is now the case in many mega-cities where the drinking water supplies from rivers or local groundwater sources are no longer sufficient, mostly because of their poor quality. The lack of sanitation facilities and the too often associated unsafe drinking waters remain among the principal causes of disease and death, especially in rural areas. Specific measures to counteract water-related threats are often needed, but, lack of investments and inadequate local management often lower their effectiveness. Institutional manageability The scope and success of any effluent use scheme will depend to large extent on the administration skills applied. Wastewater reuse is characterised by the involvement of several departments and agencies, either governmental or private or both. In the NENA countries, few governmental agencies are adequately equipped for wastewater management. In order to plan, design, construct, operate and maintain treatment plants, appropriate technical and managerial expertise must be present. This could require the availability of a substantial number of engineers, access to a local network of research for scientific support and problem solving, access to good quality laboratories and monitoring system and experience in management and cost recovery. In addition, all technologies, included the simple ones, require devoted and experienced operators and technicians who must be generated through extensive education and training. For adequate operation and minimization of administrative conflicts, a tight coordination should be well defined among the Ministries involved such as those of Agriculture, Health, Water Resources, Finance, Economy, Planning, Environmental Protection and Rural Development. The basic responsibilities of such inter-ministerial committees could be outlined in: • Developing a coherent national policy for wastewater use and monitoring of its implementation; • Defining the division of responsibilities between the respective Ministries and agencies involved and the arrangements for collaboration between them; • Appraising proposed re-use schemes, particularly from the point of view of public health and environmental protection; • Overseeing the promotion and enforcement of national legislation and codes of practice; • Developing a national staff development policy for the sector; Financial considerations The lower the financial cost, the more attractive is the technology. However, even a low cost option may not be financially sustainable because this is determined by the true availability of funds provided by the polluter. In the case of domestic sanitation, the people must be willing and able to cover at least the operation and maintenance cost of the total expenses. The ultimate goal should be full cost recovery although, initially, this may need special financing schemes, such as cross subsidization, revolving funds and phased investment programmes. In this regard, adopting an adequate policy for the pricing of water is of fundamental importance in the sustainability of wastewater re-use systems. Subsidizing re-use system may be necessary at the early stages of system implementation, particularly when the associated costs are very large. This would avoid any discouragement to users arising from the permitted use of the treated wastewater. However, setting an appropriate mechanism for wastewater tariff is a very complex issue. Direct benefits of wastewater use are relatively easy to evaluate, whereas, the indirect effects are “non monetary issues” and, unfortunately, they are not taken into account when performing economic appraisals of projects involving wastewater use. However, the environmental enhancement provided by wastewater use, particularly in terms of preservation of water resources, improvement of the health status of poor populations in rural areas, the possibilities of providing a substitute for freshwater in 124 water scarce areas, and the incentives provided for the construction of sewerage networks, are extremely relevant. They are also sufficiently important to make the cost benefit analysis purely subsidiary when taking a decision on the implementation of wastewater re-use systems, particularly in poor and rapidly growing rural villages. Monitoring and Evaluation Monitoring and evaluation of wastewater use programmes and projects is a very critical issue, hence, both are the fundamental bases for setting the proper wastewater use and management strategies. Ignoring monitoring evaluation parameters and/or performing monitoring not regularly and correctly could result in serious negative impacts on health, water quality and environmental and ecological sustainability. Unfortunately, in many MENA countries that are already using or start using treated wastewater as an additional water source, the monitoring and evaluation programme aspects are not well developed, are loose and irregular. This is mainly due to the weak institutions, the shortage of trained personnel capable of carrying the job, lack of monitoring equipment and the relatively high cost required for monitoring processes. Public awareness and participation This is the bottleneck governing the wastewater use and its perspective progress. To achieve general acceptance of re-use schemes, it is of fundamental importance to have active public involvement from the planning phase through the full implementation process. Farmers will need to be convinced that treated wastewater can provide an attractive resource and they can save money through reducing the fertilizer application. Some observations regarding social acceptance are pertinent. For instance, there may be deeprooted socio-cultural barriers to wastewater re-use. However, to overcome such an obstacle, major efforts are to be carried out by the responsible agencies. Responsible agencies have an important role to play in providing the concerned public with a clear understanding of the quality of the treated wastewater and how it is to be used; confidence in the local management of the public utilities and in the application of locally accepted technology, assurance that the re-use application being considered will involve minimal health risks and minimal detrimental effects on the environment. In this regard, the continuous exchange of information between authorities and public representatives ensures that the adoption of specific water re-use programme will fulfill real user needs and generally recognized community goals for health, safety, ecological concerns programme, cost, etc. In this way, initial reservations are likely to be overcome over a short period. Simultaneously, some progressive users could be persuaded to re-use wastewater as supplementary source for irrigation. Their success would go a long way in persuading the initial doubters to re-use the wastewater available. Realistic Standards and Regulations An important element in the sustainable use of wastewater is the formulation of realistic standards and regulations. However, the standards must be achievable and the regulations enforceable. Unrealistic standards and non-enforceable regulations may do more harm than having no standards and regulations because they create an attitude of indifference towards rules and regulations in general, both among polluters and administrators. As the WHO microbiological guidelines expect certain levels of wastewater treatment, their enforcement in situations without any realistic option for treatment would stop hundreds or thousands of farmers from irrigating along 125 increasingly polluted streams, and put their livelihoods at risk, but would also affect food traders and general market supply. Without question, the enforcement of microbiological guidelines or crop restrictions remains important, but a better balance between safeguarding consumers’ (and farmers’) health and safeguarding farmers’ livelihoods should be made, especially in situations where the required water treatment or agronomic changes are unrealistic. However, further research is needed into hygienic food marketing as well as the safe food preparation at home as important options to tackle the wastewater problem in low-income countries. Most often, WHO guidelines have often been used, or cited in isolation from the other protective measures. If water quality, however, cannot be guaranteed, agricultural engineers should investigate possibilities of alternative irrigation technologies and irrigation methods reducing farmer’s exposure. Also, in certain case additional treatment (up to tertiary level) to remove crop restrictions will help change farmers attitude, as this will allow them to grow cash crops (vegetables). STRATEGIES FOR SUSTAINABLE REUSE IN RURAL AREAS In order to achieve safe and successful wastewater reuse schemes for irrigation purposes, WHO health guidelines should be integrated with FAO for water quality guidelines for irrigation purposes. Accordingly there are common multi strategies ultimately combined the optimisation of crop production and protecting the human heath. These are related to wastewater treatment level, restriction of the crop to be grown, irrigation techniques and scheduling, as well as to control of soil salt accumulation, ground water nitrogen pollution. Adequate treatment technology The implementation of low cost treatment is recommended. Properly designed, adequately implemented wastewater reuse is an environmental protection measure that is superior to discharge treated wastewater to its end use of the reclaimed effluent need to meet the guidelines, taking into consideration the economic constrains. Usually the wastewater of rural population does not contain heavy metal, which means that the main concern of treatment will focus on the pathogens removal. Several technologies have been described in this paper to be adapted on the socio-economic conditions of the local population. Crop selection Based on the WHO guidelines, crops to be used grouped in three categories (A, B, and C) depending on the degree to which health protection measures are required. Secondary effluent allow the cultivation of green fodder, olives, citrus, bananas, almonds, and even to be used as supplement irrigation for cereal crops. However, crop selection should be subject to their tolerance to salinity, soil characteristics, and the risks of ground water pollution. Irrigation techniques and scheduling The selection of irrigation techniques mainly depends on the quality of the effluent, the crop patterns, and the potential health risks. Irrigation techniques, which wet only the roots and not the leafy part of vegetables, were suggested as good practice for minimizing risk of contamination. Bed and furrow irrigation, drip systems and any other technique applying water close to the root systems was suggested. There is a further advantage in that there will be less infiltration of nitrogen into groundwater (Mojtahid and al 2001). Rotating wastewater application over fields if this is possible is another means to limit over-fertilisation and pollution of groundwater. Avoiding irrigation with wastewater in the two weeks before harvest can minimize the risk from pathogen contamination of leafy vegetables, but this necessitates a fresh water source accessible to farmers, which is rarely possible in these rural situations. 126 Control of nitrogen pollution and salt accumulation Farmers should calculate the amount of nitrogen needed taking into account the amount of nitrogen supplied by the treated wastewater. Some crops are highly effective in removing nitrogen from soil, which may contaminate underground water. Sudan grass, Rhodes grass, maize, sorghum remove nitrogen efficiently from the soil. High sodium levels in treated wastewater can reduce water infiltration in heavy clay soil, and could not be tolerated by salt sensitive crops. Gypsum and organic amendment will reduce the negative effect of the sodium on the soil structure and improve crop productivity under these conditions. Also the use of more tolerant species, associated with some good practices (irrigation techniques, leaching ….) will reduce the salt effect on the crop yield. CONCLUSION AND RECOMMENDATIONS Domestic WWTR is one tool to address the food and water insecurity facing many countries in the Near East and North Africa. In coming years, in most NENA countries, valuable fresh water will have to be preserved solely for drinking, very high value industrial purposes, and for high value fresh vegetables crops consumed raw. Where feasible, most crops in arid countries will have to be grown increasingly, and eventually solely, with treated wastewater. The economic, social and environmental benefits of such an approach are clear. To help the gradual and coherent introduction of such a policy, which protects the environment and public health, governments shall have to adapt an Integrated Water Management approach, facilitate public participation, disseminate existing knowledge, and generate new knowledge, and monitor and enforce standards. Awareness and information efforts targeted at farming communities, including in particular at women, improved specialized extension services and assistance in marketing crops grown under safe planned reuse schemes be useful steps in improving reuse. To ensure the sustainability of the system, a cost recovery analysis should not be neglected. The low income of most farmers, it is not realistic to expect farmers to pay any portion of the treatment cost, but tariffs should cover the cost of transferring and distribution of the reclaimed water. On the technology side, small-scale decentralized sanitation technology, such as lagoons, sand filters, constructed wetland, and even septic tanks combined with small-bore sewers, offer great potential in small rural areas. As far as irrigation technologies are concerned, bubbler irrigation may be considered the preferred method of application particularly for tree crops. It provides some water savings, and also provides some degree of protection against clogging and contamination exposure. REFERENCES Abu-Zeid, M (1992). Egypt efforts towards management of agricultural water demand, National Water Research Center, MPWWR. Egypt. Abu-Zeid, M (1998). Recent Trends and Development: Reuse of Wastewater in Agriculture, International Journal on Environmental Managment and Health, MCB University Press, ISSN 0956 6163, Volume 9, Number 2&3. Ayres, RM, Alabaster, GP, Mara, DD, and Lee, DL. (1992). Design Equation for Human Intestinal Nematode Egg Removal in Waste Stabilization Ponds. 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Technical report series no. 517, World Health Organization, Geneva. W.H.O., (1992). The International drinking water and sanitation decade. Review (as at December, 1990). W.H.O./CW5/92.12. World Health Organization, Geneva. W.H.O., (1990). Legal issues in water resource allocation, wastewater use and water supply management. Report of consultation of FAO/WHO working group on legal aspects of water supply and wastewater management. Geneva 27 Sept. 1990. World Health Organization, Geneva. WHO. (1989). Health guidelines for the use of wastewater in agriculture and aquaculture. Report of a WHO Scientific Group. Geneva, World Health Organization, 1989 (WHO Technical Report Series No. 778). 128 PLANNING FOR WASTEWATER REUSE F. Fresa *, F. Melli **, A.F. Piccinni *, V. Santandrea *** and V. Specchio * * Polytechnic of Bari, via E. Orabona 4 70126 Bari – [email protected] ** SOGESID s.p.a., *** IPRES Istituto Pugliese di Ricerche Economiche e Sociali SUMMARY- This paper presents the results of a research work aimed at defining useful criteria for planning treated wastewater reuse. All the possible forms of reuse are preliminarily analysed, supplementary treatments required for different uses are identified according to reclaimed water characteristics, and the additional costs required to adjust the treatment plants to the reuse purposes are estimated; the implications related both to the organizational and management problems of the treatment-reclamation system and to the methodological and technical aspects relative to waterpricing policies are also analysed. INTRODUCTION Faced with worsening environmental problems, planning and management strategies of wastewater reuse both as an additional resource to keep up with increasing demand and as environmental protection tool to turn wastes into resources are a must. Correct knowledge of the dynamics related to water reuse and the resulting possible scenarios are a prerequisite for correct planning of actions on the territory; local as well as regional and national planning has necessarily to consider problems related to the definition of wastewater quality standards and optimal treatments to make waters adequate for different uses, to the definition of the environmental benefits and risks related to reuse policies and, in cost-benefit terms, to the identification of an economic return threshold for the required reuse works to be implemented. In that sense, the main obstacle to treated wastewater reuse is the treated wastewater cost to be charged to users, since distribution costs add up to treatment costs. On the contrary, if we consider reuse as a wastewater disposal tool, or better to say a “non-disposal” tool, in that it is by itself an environmental benefit, it can be assumed that part of treatment costs should be borne by the community, that being the primary beneficiary of pollution abatement. Such an assumption is in line with the Directive 2000/60/EEC (that establishes a framework for the community action in the matter of waters and that follows on the directive 91/271/EEC) where art. 9 (Recovery of costs for water services) states in paragraph 1: “Member states shall take account of the principle of recovery of the costs of water services, including environmental costs …, and in accordance in particular with the polluter pays principle” Such preliminary remarks that anticipate some of the conclusions of this paper, are needed to justify the spirit and approach of this work that moves through broad though not fully and explicitly reported evaluations to recognize wastewater reuse an environmental rather than an economicproduction value. In agriculture, for instance, wastewater reuse will be a small amount of the resource globally necessary but it will be strategic for some areas with severe water scarcity. The strategic value of such a resource is related to its being a substitute for the water currently used, thereby contributing to reduce indiscriminate abstraction. Of course, in areas subject to significant groundwater withdrawal, the use of wastewater has to be accompanied by a plan to prevent on-going abstraction. SECTORS OF POSSIBLE REUSE The possible sectors of wastewater reuse mainly fall into four categories: agricultural, industrial, urban and environmental-recreational. Table 1 shows the main uses within each of these categories each of them having specific and different characteristics both in terms of water quality and distribution modes, with inevitable effects on the technologies to be adopted (starting from advanced treatments downstream the standard treatment). 129 In any case, implementing wastewater reuse requires defining quality criteria to comply with two fundamental conditions: − − To make water suitable for the specified reuse; To protect in any case the involved population and workers from direct or indirect sanitary risks related to reuse as well as, more generally, to protect the environment from contamination risks. Table 1. Reuse categories – major risks and constraints AGRICULTURAL CATEGORIES OF REUSE Wood production Fodder production Fruit production Production of processed and cooked food Production of food to be eaten fresh LANDSCAPE Irrigation of public and private green areas Municipal uses (water closet effluents) Wash of roads, buildings, vehicles INDUSTRIAL ENVIRONMENTAL Air conditioning Groundwater recharge Control of salt water intrusion Control of subsidence phenomena Artificial wetland or supply in wetland Impoundments and ponds for recreational purposes (fishing, bathing…) Cooling water Boiler feed water Process water MAJOR RISKS AND CONSTRAINTS TO DEFINE EFFLUENT QUALITY REQUIREMENTS AND MODES OF USE Possible health-sanitary risks due to the presence of pathogens (viruses, bacteria and parasites); possible soil and groundwater pollution (persistent organic compounds, nitrates, metals, dissolved solids); product acceptability on the market Possible health/sanitary risks due to the presence of pathogens; corrosion effects, dirtying and plugging of delivery systems; possible interconnection with drinking water waterworks with possible resulting health/sanitary risks Possible health/sanitary risks due to the presence of pathogens; possible groundwater pollution. Possible eutrophication; toxicity to aquatic life Possible health/sanitary risks for the production of aerosols in cooling towers; effects of corrosion, dirtying and plugging; interference in the process. In the economic analysis we considered the types of reuse more easily feasible, among the reported ones, and for which the economic factor plays a fundamental role, that is agricultural and industrial reuse. In the case of reuse for industrial purposes, the operation cycle of facilities can be planned on yearly basis, whereas reuse for agricultural purposes concentrates the regime operation cycle of facilities in the irrigation season that generally extends from April to October, each month having different climatic patterns and precipitation regimes. In the framework of optimal management of reused water for irrigation purposes, reuse could serve to meet the basic demand and water from other sources could supplement the water resource in peak periods: we refer to such practice as “supplemented irrigation”; as explained later, it allows reusing greater amounts as compared to the assumption of meeting the irrigation demand through wastewater only. The following tables gives the monthly consumption coefficients used in the three assumptions of use and the resulting reuse potential. Of course, the reuse potential with respect to the discharge potential is minimum in the case of reuse for irrigation, and maximum in the case of reuse for industry. 130 Table 2. Consumption coefficients per type of use Months Irrigation (%) (1) Supplemented irrigation (%) Industrial April May June July August September October 0.22 0.61 0.96 1.00 0.96 0.48 0.13 0.36 1.00 1.00 1.00 1.00 0.80 0.20 300 days/year (1) Viparelli’s assumption, 1981 Based on these assumptions, the reuse potential is lower than the discharge potential in a percentage that differs depending on the type of use (Table 3). Table 3. Reuse potential with respect to the discharge of facilities Type of use % rate of use Industrial 82.1 Supplemented irrigation 44.2 Irrigation 34.0 POTENTIALS OF REUSE FACILITIES The economic evaluation of the cost of reuse, both in terms of investment and of management costs, was performed on the basis of the type of reuse (irrigation and industry) as well as of the plant potentials, of the pre-existing treatment chain, of the possible supplemental treatment technologies depending on the quality of discharge (into the soil or receiving water) and of operational environmental conditions. Facilities were subdivided into two macro-categories, depending on the effluent quality threshold levels and thus of the treatment components required to achieve them: − − Type A facilities: those for which effluents are discharged into large receiving water or into the sea and where the effluent denitrification and tertiary treatment unit is not present; Type B facilities: those for which effluents are discharged into the soil, and where effluent denitrification and tertiary treatment are present (filtration). Then, wastewater treatment facilities were subdivided into potential classes, determined according to the number of inhabitants served and of three assumptions of water discharge, defined on the basis of the assigned water supply value, “low”, DI1, “medium”, DI2, and “high”, DI3 (Table 4). Table 4. Values of water supply assumed in the computation example. Values are expressed in litre/inhabitant*day. Population class Number of inhabitants Computation assumption DI1 DI2 DI3 1 Smaller than or equal to 10,000 250 300 350 2 Greater than 10,000 and smaller than or equal to 100,000 350 400 450 3 Greater than 100,000 450 500 550 131 Actions to adapt the effluent treatment lines for reuse were defined by taking as a “basic” facility a scheme that ensures biological removal of biodegradable organic matter, diversified by the presence or absence of primary sedimentation and of the tertiary treatment stage related to the quality of discharge. Based on the pollutant concentration limits established under the European regulation in force and taking into account “conventional” technologies and treatment processes, the following supplementary treatment stages were considered: − − Biological stage to remove nitrogen; Chemico-physical stage to remove fine solids and pathogenic micro-organisms. The first treatment is assumed to be implemented by integrating an active sludge scheme with a pre-denitrification stage; the second treatment is assumed to be accomplished through “direct” filtration on granular beds, with in line coagulation, followed by a disinfection stage. In particular, for the filtration stage, economic comparisons led to choose pressure filters for class 1 and class 2 facilities, and gravity filters for higher potential facilities, i.e. class 3. As for disinfection, two different treatment lines were analysed: the first one included only one chlorination stage, whereas the second one included two stages in series: a stage with ultraviolet radiations followed by a stage with the addition of peracetic acid as safety disinfectant. We didn’t consider the adaptation interventions relative to the processing units that do not require substantial additional building or operational works, like the primary and secondary sedimentation stages and the whole sludge treatment line. In this respect, we should consider that for the considered facility schemes, the increase in sludge production, attributable to greater efficiency in the removal of suspended solids, is substantially compensated by lesser production of biological sludge as a result of older sludge adopted in nitrification-denitrification processes. Finally, assuming reuse for irrigation purposes, the nitrification-denitrification process was designed for an average temperature of 20°C (reuse in the spring-summer period), whereas in the case of industrial reuse (all year around) the design temperature was assumed to be 13-15°C in the winter period and constantly 20°C under summer operation conditions. This differentiation resulted in a considerable increase of the denitrification volume since these processes highly depend on temperature. In the Table 5, the supplementary actions to comply with the limits for reuse established under the Italian regulation are reported according to the effluent quality of the existing treatment facility. Table 5. Conventional treatments required for adapting treatment facilities depending on the discharge quality for reuse purposes. Treatment stages required for complying with the effluent quality limits for reuse Biological treatments Chemicophysical treatments 132 Nitrogen removal Quality of treated discharge Type A Type B Nitrification REQUIRED NOT REQUIRED Denitrification REQUIRED NOT REQUIRED REQUIRED NOT REQUIRED REQUIRED POSSIBLE ADAPTATION Defosfatation Removal of Filtration suspended Coagulation solids Disinfection REQUIRED ADAPTATION TECHNICAL-ECONOMIC ANALYSIS The technical-economic analysis was performed referring to the cost indexes of 2004 and thus, the corresponding costs were assessed as to that date; the use of the data referred to different time horizons have to be discounted through adjustment indexes. However, this is a marginal aspect since the aim of this research is to define planning criteria for wastewater reuse, and comparing scenarios is thus more important than considering the absolute value of each single cost unit. The analysis of wastewater treatment facilities concerned: a) b) The identification and estimate of the additional costs required to adapt treatment facilities, depending on the effluent quality (Type A/Type B), to the parameters imposed for reuse; Aspects related both to the organization and management problems of the treatment-reclamation system and to the methodological and technical aspects relative to water-pricing policies. Such a distinction is important in that, for the time being and in theory, it is possible to have three different management bodies for the reuse cycle: one for the treatment facilities, another for the reuse facilities and another one for the facilities of use. Of course, such a structure should not affect the fixation of cost regimes and, consequently, of water-pricing. Cost analysis was based on the assumption of considering not the capital and management costs of a completely new reclamation facility, but the additional capital and management costs to reach, from standard quality parameters effluent, the reference parameters for reuse. Cost analysis has taken into consideration the “additional” treatment for reuse (Table 6), subdivided into two major items: − − Investment/capital costs, estimated as a function of public funding or through borrowing from the financial market; Operational costs and further broken down into: − − Fixed costs, i.e. the costs independent of the type of reuse: the costs falling within this category are those that do not vary in size with the variation of the amount of reuse of treated effluents; Variable costs, i.e. the costs dependent on the kind of final use: the costs that fall within this category are those that vary in size with the variation of the amount of reuse of treated effluents. Table 6. Breakdown of additional costs FIXED COSTS • • Capital costs/ Financial costs Building works Electromechanical supplies • • Operational costs Personnel Maintenance and replacement of parts VARIABLE COSTS • • Operational costs Energy costs Reactants Table 7 shows the different additional cost items of treatment stations. 133 BUILDING WORKS ADAPTATION OF FACILITIES CONSUMPTION OF CHEMICAL REACTANTS POWER CONSUMPTION --- MIXING OF BIOLOGICAL SLUDGE --- ADDITIONAL AERATION RECIRCULATION OF MIXED LIQUOR AND SLUDGE SUBMERGED MIXERS INCREASED AERATION (COMPRESSORS AND DIFFUSERS) PRECIPITATION OF PHOSPHORUS DOSAGE AND MIXING OF REACTANTS DOSAGE OF REACTANTS ACCUMULATION OF REACTANTS COAGULATION AGENT DOSAGE AND MIXING OF REACTANTS METER PUMP OF REACTANTS AND RAPID MIXER TANK OF RAPID MIXTURE OF REACTANTS --- --- BACKWASHING OF FILTERS LIFTING FOR PRESSURIZED SUPPLY BACKWASHING UNIT FEED PUMPS PRESSURIZED RESERVOIRS BACKWASHING TANKS --- INCREASE IN VOLUME OF THE OXIDATION REACTOR --- BACKWASING OF FILTERS BACKWASHING FACILITIES FILTRATION TANKS AND FITTINGS GRAVITY FILTERS PRESSURE FILTERS COAGULATION CHEMICAL PRECIPITATION NITRIFICATION RECIRCULATION OF MIXED LIQUOUR AND INCREASE IN SLUDGE RECYCLE REACTOR PRE-DENITRIFICATION SUSPENDED SOLIDS REMOVAL CHEMICO-PHYSICAL TREATMENTS WATER TREATMENT PROCESSE S REMOVAL OF PHOSPHORUS REMOVAL OF ORGANIC MATTER AND NITROGEN BIOLOGICAL TREATMENT Table 7. Cost items of treatment stations COSTS INVESTMENT COSTS OPERATION COSTS ELECTROMECHANICAL SUPPLIES 134 INCREASE IN RADIATION PRODUCTION --- INCREASE IN THE DISINFECTANT AGENT AND REACTANTS DECHLORINATION INGCREASING RADIANT LAMPS INCREASING CONTACT TANKS ULTRAVIOLET RADIATION ---- ---- INCREASING CONTACT TANK CHLORINE COMPOUNDS ADDITION DISINFECTION Analysis of capital costs Capital costs analysis has taken into consideration the building works and electromechanical supplies. The costs of building works are evaluated net of possible costs for expropriating new areas. The considered works are illustrated in the following box: Table 8. Schematic capital costs* analysis Types of costs Building works Excavation / backfills, impoundments, flooring asphalt, fencing Pressure filters Gravity filters Electromechanical supplies blowers mixers mixed liquor pumps pressurized filtration: − filters - lifting plant for filtration − lifting plant for backwashing − blowers gravity filtration: − nozzles − hydraulic valves − electrical facilities − lifting plant for filters − lifting plant for backwashing − filter blowers − miscellaneous UV lamps Electromechanical supplies relative to reactants: Meter pump Measurement Unit Unit cost € €/m3 150 €/m3 €/m3 150 400 €/Nm3/g €/N €/KWh min 0.21-max 2.81 min 5.08–max 16.67 min 5.05-max 16.66 €/m2 €/kWh €/kWh Nm3/g min 8,560-max 10,700 min 648-max 1,500 min 648-max 1,500 min 0.21-max 2.81 units €/filter €/filter €/kWh €/kWh nm3g €/m3 units 0.70 15,000 1,500 min 648-max 1,500 min 648-max 1,500 min 0.21-max 2.81 4,80 min 2,500-max 11,750 units 900 / N.B. for type B facilities the additional costs concern UV lamps and dosage unit Table 9. Adaptation costs of type A facilities Facility potential (AE) Building works [€] Electromechanical supplies [€] Total [€] 2,000 33,835 114,862 148,697 5,000 84,588 172,223 256,811 10,000 169,176 210,153 379,329 20,000 330,496 438,532 769,028 30,000 495,744 615,104 1,110,847 40,000 633,792 779,777 1,413,568 50,000 792,240 955,307 1,747,547 70,000 1,109,135 1,301,753 2,410,888 100,000 1,584,479 1,722,855 3,307,334 250,000 6,089,005 1,645,931 7,734,936 500,000 11,430,915 2,010,982 13,441,897 135 The minimum and maximum values indicated in the table basically depend on the potential of facilities. Based on such assumptions, the costs of investments were determined separately for the building works and for electromechanical supplies depending on the size of facilities per IE. Table 9 gives, for instance, the results obtained in the case of adaptation of type A facilities and assuming a more onerous operation of the existing facility, that is in the presence of primary treatment, at a temperature of 15°C, assuming to adopt the UV + peracetic acid scheme for disinfection. Based on the previous results, the cost of investments per IE was determined, again assuming type A facilities. Table 10. Unit adaptation costs of type A facilities - €/IE Type of biological treatment / IE 2,000 50,000 500,000 15° 20° 15° 20° 15° 20° With primary treatment 74.35 65.85 34.95 26.97 26.88 20.01 Without primary treatment 78.57 66.93 38.43 28.82 31.61 19.80 These results point to: 1. a considerable difference in the cost per inhabitant equivalent depending on the size of facilities (difference of about 50 euros between small and bigger size facilities); 2. the cost difference (€/IE), depending on the presence or absence of primary sedimentation, ranges between 12.9% and 34.4% at 15°, between 17,4% and 59.6% at 20°. Similarly for type B facilities, considering the costs given in table 4.3, the investments costs briefly illustrated in table 4.6 are obtained. Table 11. Additional costs for the adaptation of type B facility Facility potential (IE) Electromechanical supplies [€] 2,000 48,724 50,000 252,136 500,000 512,847 The comparison between Tables 8 and 9 shows considerable reductions with respect to the previous assumptions - they are significant in absolute values – since we move from about 100,000 € for facilities of 2,000 IE to about 13,000,000 € for facilities of 500,000 IE for the overall investment costs. Analysis of operational/management costs The analysis of operational costs considered the following items: − Personnel costs; − Cost for dosage of reactants; − Power consumption; − Costs for maintenance and replacement of parts; − Financial costs. In the global calculation, the economic return of investments was not taken into account, since increases in return are fixed as objectives of the Institutional Bodies in charge of determining both the water price and its variation. 136 The gain in productivity objectives were not taken into account, since they are fixed by the Institutional Bodies in charge. For the purposes of the global impact on water price, the two above-mentioned components produce opposite effects: economic return produces an increase in the total cost per m3, whereas gain in productivity produces a reduction; therefore, the global effects depend on how big or how small such values are. From the performed analysis, it came out that depending if adaptation works refer to type A or type B facilities, and thus depending on the importance of adaptation interventions for reuse purposes, substantial changes are observed for these items of costs. In the case of additional interventions on type B facilities, the following cost items considerably decrease: − − − The costs for the personnel, in that it necessitates a minimum amount of working hours for chemical control; nevertheless, it is more profitable to have management performed by the managing body of the treatment facility rather than using external entities. The costs for power consumption, since they concern the consumption relative to UV lamps and the operation of dosage facilities; Financial costs, so much so to make the difference between public and no public funding not significant; this occurs because investment costs are almost non-existent. No significant variations are observed for the costs of reactants used in the two assumptions. Analysis of personnel costs The analysis of the cost of the personnel was based on two assumptions: 1. Management of works, of reclamation facilities and the corresponding control performed by the managing body of the treatment facilities; 2. Management of works, of reclamation facilities and corresponding control performed by a body other than the managing body of the treatment facilities. This double assumption is based on the consideration that some saving could be possible in the use of the existing personnel of the treatment facility managing body, as compared to the second assumption. In the first assumption, an additional activity was assumed only for the head of the facility since the other professional profiles (chemists, facility maintenance personnel) can be suitably employed without additional costs. In the second assumption, i.e. entrusting this task to an external management body, it requires a dedicated organization that inevitably leads to higher costs per facility. The comparison between the first and the second hypothesis highlights possible saving in the use of existing personnel in favour of the manager of the treatment facilities. Analysis of reactant costs The analysis of additional costs of reactants has taken into account three types of reactants needed to adapt the existing facilities to reuse parameters: − − − Aluminium polychloride at 15% for coagulation in line; Sodium hypochlorite at 12% of Cl2 for disinfection; or alternatively Peracetic acid in solution at 15%, with bacterio-static function to be combined with UV rays treatment. Costs of power consumption The costs of power consumption were calculated as a function of the potentials of facilities and of reference temperatures for nitrification and denitrification (15° and 20°C), attributing a unit cost of 0.1 137 €/KWh, on the basis of the subscribed demand and the corresponding power consumption for each of the electromechanical supplies. Power consumption and corresponding costs were estimated for the following machinery: blowers, mixers, return pumps, UV rays, pressure filters (filters, lifting plant for filters, lifting plant for backwashing, blowers), gravity filters (electrical equipment, lifting plant for filters, lifting plant for backwashing, blowers), machinery relative to additional reactants (dosage plant). Maintenance costs and replacement of parts Maintenance costs of building works and electromechanical supplies were estimated on the basis of the following assumptions: − − building works: a life cycle of the investment equal to about 25 years was assumed, with a maintenance cost equal to an average yearly rate of 1% on the amount of the whole cost of specific investment; electromechanical supplies, in view of both increased wear and tear in operation and of the need of replacing mechanical parts, an average life cycle of 8 years was assumed, with a yearly maintenance rate of 5% out of the amount of the whole specific investment cost. Table 12. Maintenance and replacement of parts Yearly maintenance rate Type of works Life cycle Building works 25 years 1% Electromechanical machinery 8 years 5% Financial costs Capital costs fall within the operational/management costs in the form of financial and depreciation costs in relation to the type of funding of building works and electromechanical supplies. Therefore, these costs were estimated on the basis of the following assumptions: − − with public funding of the investment, in this case financial costs concerned only linear technical depreciation with the assumption of building up the invested public capital; without public funding of the investment, in this case the financial costs concerned, on one hand, the share in the capital and, on the other hand, the share of interests, with the assumption of having recourse to funding through loan. A further and more complex hypothesis, i.e. having recourse to external funding with venture capital, was not considered since it also requires assumptions on the type of legal structure of the managing body and the subdivision of risk for the determination of risk rates to be included in the financial costs. The assumptions for the two considered hypotheses are shown in Table 13. Table 13. Hypothesis of financial cost of investments 138 Type of works Life cycle Yearly rate of interest 7% (a) Linear depreciation rate (b) Building works 25 years Financial rate 0.0858 Depreciation rate 4% Electromechanical machinery 8 years Financial rate 0.1674 Depreciation rate 12.5% A significant cost incidence difference is evident between the two hypotheses: • • building works – difference of 115% per year electromechanical supplies – difference of 34% per year. GLOBAL RESULTS OF ANALYSES Based on the assumptions and hypotheses illustrated in the previous chapters, a general picture of the economic analysis is outlined. The final results are presented, first for the hypothesis of type A facilities and then for type B facilities, assuming the presence of primary treatment, temperature of 15°, dosage of reactants combined with UV. The last hypothesis is more onerous than the others. First of all, the results of the annual costs in absolute values and in m3 for the three types of small (2,000 IE), medium (50,000 IE) and big size (500,000 IE) are given. The analyses were performed assuming three types of possible uses (industrial, irrigation and supplemented irrigation) to which correspond - the facility being equal - different values of reclaimed water volumes with respect to which the unit cost is evaluated. Table 14. Total yearly cost for the adaptation and management of type A facilities – Primary treatment – 15° - Without public funding – Internal Management – Hypothesis of UV reactants – Values in € OPERATIONAL COSTS /IE A. Fixed costs A.1 Operational costs Personnel Maintenance and replacement of parts A.2 Financial costs (1) Building works Electromechanical supplies TOTAL (A1+A2) 2,000 50,000 500,000 36,801 30,720 6,081 22,131 2,903 19,228 58,932 78,728 23,040 55,688 227,893 67,974 159,918 306,620 230,218 15,360 214,858 1,317,411 980,773 336,638 1,547,629 B. Variable costs for industry Electrical power Reactants C. Variable costs for supplemented irrigation Electrical power Reactants D. Variable costs for irrigation Electrical power Reactants 12,771 4,926 7,845 384,095 122,606 261,490 3,817,732 549,112 3,268,620 6,845 2,640 4,205 5,568 2,148 3,420 205,875 65,717 140,158 167,466 53,456 114,009 2,046,304 294,324 1,751,980 1,664,531 239,413 1,425,118 TOTAL (A+B) INDUSTRY TOTAL (A+C) SUPPLEMENTED IRRIGATION TOTAL (A+D) IRRIGATION 71,703 65,777 64,500 690,716 512,495 474,086 5,365,361 3,593,933 3,212,160 C/m3 industry C/m3 supplemented irrigation C/m3 irrigation 0.55 0.95 1.14 0.16 0.22 0.27 0.10 0.12 0.14 139 From Table 14, in the case of type A facilities, the following is found: − A sharp reduction in the cost per m3 per year moving from small to large size facilities; − A significant difference in cost between the different types of uses. This difference decreases both in absolute terms and as percentage, depending on the size of the potentials of facilities. The difference is about 0.6 euros per m3 between industrial and irrigation use for small size facilities (2,000 IE) and about 0.04 euro per m3 for large size facilities (500,000 IE) − Among variable costs, a significant increase in the cost of reactants. Table 15. Incidence of costs out of the total for type A facilities - % values. OPERATIONAL COSTS / IE 2,000 50,000 500,000 82.2 44.4 28.8 Industry 10.9 37.9 60.9 Supplemented irrigation 6.4 27.3 48.7 Irrigation 5.3 24.0 44.4 A. Fixed costs B. Variable costs of reactants The first effect is to be attributed to scale economy; the second one to higher consumption of reactants related to a higher use of treated wastewater, for larger size facilities. Secondly, minimum economic return thresholds for further interventions are possible for facilities greater than 50,000 IE. Quite significant results are obtained for facilities greater than 100,000 IE. In the following graphs the additional costs for the three types of reuse assuming adaptation of type A facilities without funding are given together with the possible saving per m3 of reuse treated water when adaptation works are made through public funding. Industry Suppl. Irrig. Irrigat. 1.30 1.20 1.10 1.00 0.90 0.80 €/m3 0.70 0.60 0.50 0.40 0.30 0.20 0.10 AE 2 000 5 000 10 000 20 000 30 000 40 000 50 000 70 000 100 000 250 000 500 000 Fig. 1. Adaptation costs for reuse and management of type A facilities – Hypothesis without public funding. 140 Supplemented irrigation Industry Irrigation 1.30 1.20 1.10 €/m3 1.00 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 2 000 5 000 10 000 20 000 30 000 40 000 50 000 70 000 100 000 IE 250 000 500 000 Fig. 2. Adaptation costs for reuse and management of type A facilities – Hypothesis with public funding Similarly, as for the adaptation costs of type B facilities, Table 16 illustrates the results of annual costs in absolute values and per m3 for three types of small-size (2,000 IE), medium-size (50,000 IE) and large-size facilities (500,000 IE). In this respect, the following is observed: – The sharp reduction in the cost per m3 per year from small-size to large-size facilities; – The significant cost difference between the three types of uses; this difference decreases with size. This effect, also in this case, is basically due to the scale economy of facilities. 141 Table 16. Total annual cost for adaptation and management of type B facilities – Hypothesis of reactants combined with UV – Values in € OPERATIONAL COSTS /AE A. Fixed costs A.1 Operational costs Personnel Maintenance and replacement of parts A.2 Financial costs (1) Building works Electromechanical supplies TOTAL (A1+A2) 2,000 50,000 6,276 3,840 2,436 8,156 16,449 3,840 12,609 42,208 - - 500,000 29,512 3,840 25,672 85,851 - 8,156 14,433 42,208 58,657 85,851 115,363 B. Variable costs for industry Electrical power Reactants 8,745 900 7,845 276,190 14,700 261,490 3,452,520 183,900 3,268,620 C. Variable costs for supplemented irrigation Electrical power Reactants 4,687 482 4,205 148,037 7,879 140,158 1,850,550 98,570 1,751,980 D. Variable costs for irrigation Electrical power Reactants 3,812 392 3,420 120,418 6,409 114,009 1,505,298 80,180 1,425,118 23,177 19,120 18,245 334,846 206,694 179,075 3,567,883 1,965,914 1,620,662 TOTAL (A+B) INDUSTRY TOTAL (A+B) SUPPLEMENTED IRRIGATION TOTAL (A+B) IRRIGATION C/m3 industry C/m3 integrated irrigation C/m3 irrigation 0.179 0.275 0.323 0.078 0.089 0.100 0.066 0.068 0.072 As shows the Fig. 3, economic return is already evident for the small-size facilities (20,000 IE for the two types of irrigation service; 10,000 IE for industry). Industry Suppl. Irrig. Irrig. 0.350 0.300 €/m3 0.250 0.200 0.150 0.100 0.050 - 2 000 5 000 10 000 20 000 30 000 40 000 50 000 70 000 100 000 250 000 AE 500000 Fig. 3. Adaptation costs for reuse and management of Type B facilities – Hypothesis without public funding 142 Since the capital costs have considerably reduced, in this case the double hypothesis of public funding/no public funding is negligible, as shown in the next figure. Industry €/m3 Supplem. Irrigation Irrig. 0.350 0.300 0.250 0.200 0.150 0.100 0.050 2 000 5 000 10 000 20 000 30 000 40 000 50 000 70 000 AE 100 000 250 000 500 000 Fig. 4. Adaptation costs for reuse and management of type B facilities – Hypothesis with public funding COMPARATIVE ANALYSIS BETWEEN THE TWO TYPES OF INTERVENTION Based on the results of the analyses, a comparison was made of the cost estimates of adaptation of facilities and their management according to the effluent quality, i.e. of type A or type B. The following came out: − the presence of possible significant differences in additional costs for the two different effluent qualities analysed; − the presence of possible economic return thresholds and/or the indifference between both. Table 17.Additional costs* for the adaptation of facilities – UV combined reactants – 15°C Costs €/m3 Type of use / IE 2,000 Industry Supplemented irrigation Irrigation 0.55 0.95 1.14 Industry Supplemented irrigation Irrigation 0.18 0.28 0.32 50,000 Type A facility 0.16 0.22 0.27 Type B facility 0.08 0.09 0.10 500,000 0.10 0.12 0.14 0.07 0.07 0.07 *hypothesis without public funding, with primary treatment 143 Firstly, the comparative analysis shows that for small-size facilities adaptation and management costs of type A facilities are more than 3 times greater than the corresponding costs of type B facilities; for larger size facilities, a greater value – from 30% to 50% - was achieved depending on the type of use. Secondly, a great difference in cost is observed between the two uses, in particular between industrial and irrigation use. The differences in cost are equal to 0.37 €/m3 for industrial use, to 0.82 €/m3 for irrigation use for facilities of 2,000 IE; respectively of 0.03 €/ and 0.07€/m3 for larger size facilities (500,000 IE). Depending on the size of facilities, these differences tend to be smaller in absolute terms, but not in relative terms. Moreover, such differences are expectedly smaller in absolute terms when considering the hypothesis of public funding of investments. Therefore, scale economy of facilities, when assuming to use reclaimed wastewater, results in a considerable reduction in additional cost differential in absolute terms but not in percentage terms. This is quite evident from Fig. 5 In other terms, beyond 100,000 IE facilities, the difference in cost for adaptation and management of facilities with respect to the two discharge hypotheses is considerably reduced. Industry €/m3 Suppl. Irrig. Irrig. 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 0.00 2 000 5 000 10 000 20 000 30 000 40 000 50 000 70 000 100 000 250 000 500 000 Fig. 5. Cost difference per m3 assuming no public funding for type A and type B facilities. Secondly, the differences in cost between public funding and no public funding are significant: − − − For industrial uses for facilities up to 20,000-30,000 IE; For supplemented irrigation uses for facilities up to 50,000-60,000 IE; For irrigation purposes for facilities up to 60,000 IE. Beyond such thresholds, additional cost differentials, though existing, are not significant. In conclusion, the economic analysis highlights the following: 144 AE In terms of investments: a) There is a significant difference in capital cost per IE to adapt type A facilities to reuse parameters. As observed, these costs vary from a peak of about 79€ per IE for facilities of 2,000 IE to a minimum of about 20€ per IE for facilities of 500,000 IE. Capital costs are present in the operational/management costs function through the financial costs of the invested capital. In this case, the capital costs accounted for about 80% of total costs for large size facilities (500,000 IE); b) Capital costs to adapt type B facilities to reuse parameters are not significant, since they are almost completely negligible with respect to operational costs. In terms of operational/management costs: c) There are significant differences in additional cost per treated m3 for type A facilities smaller than 50,000 IE. Such cost differentials are greater for irrigation use as compared to industrial use. Such differences in cost are not significant for facility threshold greater than 50,000 – 60,000 IE and concern the three analysed uses. Moreover, significant cost differentials are observed between investment funding through public resource and bank loans for facilities up to about 50,000 IE; beyond this threshold no significant absolute differences are evident. d) Adaptation costs of type A facilities are considerably greater than the adaptation costs of type B facilities. However, if measured in absolute terms, cost differentials of adaptation of the two types of facilities are significantly higher for facilities around 50,000 IE. For larger size facilities, economies of scale have significant effects, with the fundamental and crucial assumption of effective use of treated wastewater. MANAGEMENT ASPECTS Finally, the management model and the procedures for water-pricing regimes were examined. The wastewater reclamation process for reuse is one step of the Integrated Water Service. Based on this assumption, the IWS would consist of four components: waterworks, sewage, treatment, and additional advanced treatment for reuse. Based on such considerations, the following situations might exist, with reference to the management model and the fixation of the corresponding tariffs to cover capital and management costs: The holder of the treatment facility is the same as for the reclamation facility The holder of the treatment facility is different from the holder of the reclamation facility Water price fixed by the holder of the treatment facility; in this case, the price to recover additional costs are intended to be charged to the integrated water service, or to the community; therefore, treatment price fixation includes the additional cost for reclamation; Water price to cover the additional installation and management costs of reclamation, fixed by the holder of the latter; Price charged to the holder of the treatment facility, or to the community. According to this scheme, in the first case where the holder of treatment facilities is the same as for reclamation facilities, the additional price to cover the reclamation costs for reuse can be: − Charged to the integrated water service (positive increase in price); − Paid through increasing productivity (no effect on the cost recovery); 145 − Charged to the State or the Regions that cover additional reclamation costs through public contribution (no effect on the value and variations of prices). In the second case, where the holder of the treatment facility is not the same as for reclamation facility, the additional water price to cover reclamation costs for reuse can be: − − Charged to the holder of the treatment facility (effect to be analysed on the values and the variations of global water price, depending on the gain in productivity objectives of the integrated water system, on the implementation of possible scale economies of the facilities, etc.); Charged to the State or the Regions that cover the additional costs of reclamation through public contribution (no effect on the values and variations of global water price). The performed analysis highlighted that there is an economic-management return in the case of a single holder of the IWS whose competence is also extended to wastewater reclamation. First of all, the reclamation process has an additional impact in terms of physical investment, of chemical treatments and type of management with respect to the on-going treatment process, so that scale economies can be adopted especially for some fixed installation and management costs and depending on their size. Secondly, with a single holder of the IWS extended to the reclamation stage, the process of covering additional costs for reclamation would be more properly solved. In fact, from the economic viewpoint, assuming that investment costs in fixed capitals are public, a double question is raised: 1. “who pays for the additional reclamation costs” of reclaimed waters; 2. additional costs for reclamation, as shown by the economic analysis, cannot be “transferred” downstream to the end user, as it is the case under the present regulation of some countries including Italy, and they have thus to be covered “upstream the process”. In the case of a single holder, the reclamation cost should be part of the methodology to define the model for price fixation of the IWS and, subsequently, of the determination of the price cap procedure for the price variation depending on the different objectives (productivity, quality, social sustainability, etc.). CONCLUSIONS All the above can hardly lead to some conclusions since, in any case, planning of investments on reuse cannot be solely based on technical-economic considerations. “Choosing reuse” cannot leave aside some contingent aspects related, for instance, to irrigation suitability and environmental condition of the territory where actions are taken; therefore, attention is drawn on some indications that could orient planning in order to make choices and fix priorities. − Priority should be given to the areas subject to groundwater impoverishment: supplying a − − − − 146 substitute, economically competitive resource is the first step towards reclamation. In the cases where reuse is to the benefit of existing irrigation areas, a double benefit would be obtained: a reduction in the cost of intervention and immediate use of the resource since the irrigation practice will be consolidated. Investment economies will be possible in the facilities for which reuse treatment units are already present but where the facilities for use have not been identified yet. Planning should also take into account the huge irrigation demand of some highly suitable agricultural areas that, due to their geographic location and bad groundwater conditions, have no other resource available. Works in need of structural integrations need to be completed to be operational: in order not to make the performed investments fruitless and to prevent rapid degradation of the implemented works, such interventions are a priority. − In the case of small potential facilities, combining the effluents of several facilities is desirable to get a quantitatively significant reuse resource. − The “non disposal” benefit for the areas highly suitable for tourism should be taken into account. This list of considerations is not ranked in a priority order deliberately. Planning of interventions for reuse has to start always and in any case from a cost-benefit analysis that should also include the environmental benefits that are not always quantifiable. REFERENCES Cavallo L., Coco G., (2002) La remunerazione del capitale investito nelle imprese soggette a regolazione, in Economia Pubblica, anno XXXII, n. 4. Cesari G., Lotti C. (1999). Riutilizzo delle acque reflue per l’irrigazione. Giornata mondiale dell’acqua, Roma, 29 marzo. Colombo M.G., (1997). La struttura tariffaria dei servizi di acquedotto, fognatura e depurazione, PROAQUA Paper n. 97/09. Commissione CE COM 477/2000 del 26.07.2000 Fazoli R, Tiraoro L.. (2003). La regolazione Italiana dei servizi idrici nell’attività del NARS – Ministero del Tesoro e nelle deliberazioni CIPE, in Economia e Politica Industriale, n. 118. Hamdy A. Irrigation with Wastewater. In Atti del Corso Avanzato su “Riutilizzo delle Acque Reflue in Agricoltura”, Bari, 8-10 Giugno, 1992; Istituto Pugliese di Ricerche economiche e Sociali. Fabbisogni e disponibilità idriche per uso industriale in Puglia, Bacini Idrici, Regione Puglia, Aprile, 1999; Lucchetti R., Robotti L. (2000). Aspetti economici della depurazione delle acque reflue, in Economia Pubblica, anno XXX. Percolo M. (2003). cL’efficienza tecnica nel settore dei servizi idrici, in Economia Pubblica, anno XXXIII, n.5. Takashi Asano, Wastewater Reclamation and Reuse, in particular Chapter 29 “The cost of Wastewater Reclamation and Reuse”, CRC Press, 2001; 147 THE ROLE OF SMALL SCALE WASTEWATER TREATMENT IN THE DEVELOPMENT OF WATER RESOURCES IN WEST BANK OF PALESTINE M. Y. Sbeih Engineer in the Associate researcher ARIJ, P.O. Box 860 Beithlehem, West Bank Email: [email protected] [email protected] SUMMARY -There has been substantial developments in wastewater management and treatment technology worldwide during the past decades. Approximately 95% of the generated wastewater in the world as well as 93% in the West Bank is released to the environment without treatment. Wastewater has been identified as the main land based point source pollutant causing contamination of the marine environment. The increase in population and therefore in sewage production imposes a great challenge to develop and introduce sustainable sewage collection and treatment .The efforts in providing these essential services especially for poor regions of the world are hindered by the shortcomings of the current concept of water management and financial limitations. In Palestine, the only substantial water resources available are ground water. Presently the application of wastewater treatment is limited because of high cost and technology complexity of conventional systems. Seepage from domestic wastewater on-site cesspits, as well as inadequately performing off-site sewage treatment plants, demands that proper treatment should be applied at the household level to conserve the environment. Small-scale treatment plants can be effective in treating wastewater. Palestine is suffering from severe shortages of fresh water caused by Israel’s exploitation of Palestinian water resources. Predicted population growth and rise in living standards could further threaten water supplies. In light of this, wastewater is an invaluable resource that may successfully be used for irrigation upon treatment. At present, rural Palestinian areas dispose of the wastewater using cesspits, most of which have no cement base or liner allowing sewage to infiltrate into the earth, potentially polluting the ground water. Owners often avoid using the expensive services of the vacuum tankers to empty them. 12 % of Palestinian communities have wastewater collection systems while 43% of the population is connected to wastewater networks. These systems do not, however, exist in rural areas. Only one wastewater treatment plant is operating well. The uncontrolled flow of sewage causes many environmental problems and health hazards. Collection of waste water and constructing large treatment plants might be difficult in Palestine due to the great capital needed as well as the need of large areas to locate treatment plants. In addition, constructing large treatment plants requires a large area located in the same region to be irrigated by the treated wastewater. Small-scale reuse of treated wastewater for agriculture would play a major role in increasing agricultural area in Palestine as well as help to conserve the environment. PROBLEM DESCRIPTION The rural population in the West Bank, constituting around 35% of its total population, lives in more than 450 villages. There are 53 localities that have wastewater collection in the West Bank, while the rest depend on cesspits and open channels. Most of Palestinian rural population depends on agriculture to make their living and is therefore in a good position to use treated wastewater. The wastewater collection component of this system accounts for 80 to 90% of the capital cost which makes it economically unfeasible for the dispersed pattern of houses in rural areas. As a response to such a situation, ‘Small- Scale Wastewater Technology’ could be the most appropriate solution to replace current cesspit systems in rural areas of the West Bank. 149 SMALL SCALE WASTEWATER TREATMENT PLANTS IN RURAL AREAS Strategic planning and appropriate policy for wastewater management in rural areas does not exist despite the high population in these areas and lack of adequate sanitation. Recently, in 2003 the Palestinian Water Authority started to collect information on the type of the plants used in order to prepare strategy for small-scale plants. About 73% of West Bank houses have cesspit sanitation and approximately 3%, mainly in rural areas, lack any sanitation facilities. Several small-scale wastewater treatment plants have been constructed in the unsewerd rural areas of the West Bank. In addition, some applied research studies of biological treatment systems for small rural communities were recently installed and studied. Most of the recently installed rural sanitation facilities entail trickling filters and natural treatment systems preceded by septic tanks. The need for small wastewater treatment and reuse Centralized sewerage systems, the preferred choice of planners and decision makers, are inadequately provided to individual communities. In some instances wastewater is transported from several scattered communities to centralized facilities. The high cost of conventional sewers is regarded as one of the major constraints to expanding wastewater services to small communities. A world Bank review of sewerage investments in eight capital cities in developing countries found costs range between us$600-4000 per capita (1980 prices) with total household annual cost of us$15650.The conventional sewerage systems are more costly in small communities, because of their size and layout.). As example, the capital cost of construction wastewater treatment plant for ALBeireh city, with a population of 30,000, exceeds 15million USD Treating wastewater at the house level will be cheaper and easier than at the municipal level. Municipal wastewater is more than twice as concentrated as wastewater generated by individual house systems and, in addition, contains industrial wastewater, which has adverse affect on treatment hence its reuse for irrigation. Most wastewater from centralized treatment plants cannot be reused due to the invariability of land in that region that can accommodate that wastewater. In addition to the pollution of residential areas, the use of cesspits enhances pollution of groundwater. Agricultural reuse of wastewater at the household level will not require outside labor as any member of the family can work in the field any time (e.g. a student could easily manage the work after the school). In terms of marketing agricultural products, the problem will be much easier since the landlord has to market small agricultural product and he can sell them in the same village easily. On the other hand, treating wastewater at house level or even serving one small community will have the following advantages: 1. Easy to build, the owner of the house can build it (can be purchased as package i.e. just to install). 2. Cheaper, since the owner of the house can build it from his own resources while big treatment plant needs huge funding. 3. No need for external technical support. 4. Job creation for the family member. 5. Operation and maintenance since the family will cover all the operation cost, as well the cost is much less than the conventional plants which includes pumping cost, maintenance of the wastewater treatment plant and wastewater network. 6. It will act to increase public awareness, as all family members will be involved in the process. Different types of small plants have been installed in the West Bank, including: 1. UASB (Up flow And Anaerobic Sludge Blanket) 2. Sequencing Batch Reactors 3. Contact Stabilization 4. Septic Tank-Anaerobic Filter 150 Table 1. Data Related to Existing Wastewater Treatment Plants in the West Bank West Bank Treatment Plant Ramallah Al-Bireh Area served 60% of domestic wastewater/ Industrial in Ramallah city Al-Bireh city, AlAm’ari Camp, Madura CAAP/ Al-Vire Industrial Soné Population currently Served 39,950 Capacity (CM/day) 1,276 41,347 17,765 Hebron Tulare city, Tulare Camp, Nor Shams camp, ‘Anabta, western outlet of Nablus system East of Hebron City 115,443 0 Deir Samit 3600 1000 Disposal of effluent 2 Aeration lagoons Badly managed and operated (5%) Overflow pipeline discharged to Wadi Beituniya Running well (95%) Discharged to open Wades Stabilisation pond Not currently functioning (0%) Overloaded (15%) Effluent carried across Green Line into Israel where it flows to treatment plant Two sedimentatio n ponds Not currently functioning (0%) Two sedimentatio n ponds Four reservoirs containing stones Operating well (83%) Subsurface constructed wetland Not yet in service 6742 35 Nablus District 916 Sludge stabilization Three aeration lagoons Three ponds - Primary Treatment (sedimentatio n and flocculation) 5000 Hebron District 500 Sarra Status (efficiency) Extended aeration Junín Tulare Treatment type 50 Effluent from reservoirs discharged to Wade Deir Samit Effluent form sedimentation ponds – 3 collected in 50m storage tank Planned Possible non-conventional water resources in Palestine: Ground water is the only source for fresh water in Palestine. This water is extracted through wells and springs. Regarding non-conventional water there are two main possible resources: 1. Saline water: This can be either from springs and seawater 2. Treated wastewater. Utilizing saline water for irrigation is unlikely due to the high cost of desalinization .In the case of wastewater it is easier and cheaper to reuse treated wastewater for irrigation: treated wastewater is potentially available in every district and major city. The total treated amount of wastewater available for reuse in Palestine (based on 2005 figures) is 109MCM compared to 137 MCM water consumed for domestic purposes (Table 2). At present Palestine cannot utilize all of this potential wastewater due to the following constraints: a- The occupation: constructing wastewater treatment plants requires approval from Israel; it is very difficult to get this approval b- Capital needed: this is far beyond the capacity of Palestine. 93% of wastewater generated in the West Bank is untreated - there is only one functioning West Bank treatment plant (at Al Beirh). The cost of constructing a treatment plant for a city with a population of 40.000 will be in the range of 6-10million USD. 151 c- Technical problem. Due to the shortage of land and the absence of flat land it is very difficult to adopt waste stabilization ponds that capital and operation cost is kept to a minimum. If a sophisticated plant is to be constructed capital outlay including operation cost will be high which raises questions about the sustainability of plants. Due to the factors mentioned above only 53 of 450 communities in the West Bank are served by wastewater collection: the majority of these communities are only partially connected. As for treatment, there is only one city that is served by an efficient treatment plant at Al Beirh. Other cities either lack such facilities or have completely non efficient treatment plant: these are in most cases only a series of unlined ponds. This implies it will be very difficult to implement wastewater collection for villages or remote dwellings: small treatment plants that can serve one house or group of houses, even a small village, will play a major role in treating wastewater and reducing environmental pollution, as well as increasing the amount of water for agriculture. Table 2. Annual Wastewater Generation in the West Bank and Gaza Strip Districts District Nablus Ram Allah Jericho Jerusalem Bethlehem Jenin Tubas Tulkarm Qalqiliya Sal fit Hebron West Bank Dear AlBalah Gaza Khan Yunis North Gaza Rafah Gaza Strip Population (2005) 326,873 280,805 43,620 149,150 174,654 254,218 46,664 167,873 94,210 62,125 524,510 2,124,702 201,112 487,904 269,601 265,932 165,240 1,389,789 Annual Wastewater Generation / Locality Type (MCM) Rural Refugee Total Urban Areas Camps Areas 1.509808 2.153584 0.168608 3.832 0.20904 0.340704 0.074256 0.624 2.46636 2.195856 0.641784 5.304 3.61088 4.15772 0.9114 8.68 2.1852 1.4148 0 3.6 0.424128 1.079872 0 1.504 1.007136 0.73168 0.413184 2.152 3.189032 5.56444 0.598528 9.352 2.2368 3.025272 0.329928 5.592 2.498816 4.184064 0.58112 7.264 8.11504 3.657824 0.339136 12.112 3.841024 28.02747 28.1475 60.016 0.142 3.017 1.439 4.6 0.5 4.81 22.76 28.01 0.75 1.18 4.78 6.72 0.26 2.45 4.58 7.3 0.30 1.62 1.366 3.3 1.952 13.077 34.925 49.9 (Source: Arij 2006) Role of the Palestinian Water Authority: The PWA needs to announce policies as regards its regulation of work and should seek understand how it can benefit from each cubic meter of treated wastewater. The PWA is in the progress of preparing policies in this field, where cooperation between parties such as Ministry of Agriculture and Environment Authority is necessary. 152 Technical management for safe reuse of treated waster Wastewater is considered as an important potential water resource in Palestine. Hence, all efforts should be put into projects associated with the reuse of wastewater for agriculture. According to the 2002 law No.3 the PWA is responsible for wastewater treatment and reuse. The main aim of the PWA is to set policies for solving the problems caused by wastewater and to make use of the resultant potential sources through proper planning, design, implementation, and management of the sector, stressing the interdependence of water supply and sanitation services. PWA has developed policies and Strategies for wastewater treatment and reuse Waste water treatment policy: 1. Treatment plants must be signed to solve identified and potential environmental and health problems from existing and future wastewater production. 2. Industrial connections must not create environmental problems or cause problems with water treatment at plants. 3. All wastewater treatment plants must operate in accordance with permits from secured. 4. Wastewater treatment plants must be designed according to PWA regulations or document that demands will be fulfilled. 5. Treatment plants designed for less than 50 persons must be of a kind accepted by PWA and operated according to regulations 6. The potential energy in wastewater and sludge must be utilized whenever appropriate 7. Farmers should be involved in small wastewater energy recovering projects Wastewater reuse policy 1. 2. 3. 4. Treated wastewater is a valuable resource that must be utilized in an optimal way Agriculture is given priority in wastewater reuse Reuse of treated wastewater is to be performed in an environmentally and healthy way Use of treated wastewater should be co-ordinated on a national level and carried out at the appropriate local level 5. Public participation in wastewater reuse should be encouraged 6. Use of raw wastewater is considered as pollution 7. Cost/beneficial options should be considered for the optimal use of the treated effluent Waste water reuses strategy: 1. 2. 3. 4. Establish planning tools for reuse and recharge For every reuse project beneficiaries (farmers) must be involved in all project phases Reuse projects must undergo an environmental impact assessment Use of treated wastewater should be coordinated on national level and carried out on the appropriate local level 5. Public Wastewater reuse action plan: 1. 2. 3. 4. 5. 6. 7. 8. make technical guidelines for reuse for different purposes make standards for monitoring and documentation of reuse make overall plans for reuse in different sectors Planning Guidelines for reuse (public involvement, cost/benefit calculations, post treatment, etc) Make a checklist for the content of the EIA-reuse element Make an overall plan for education and training of staff and management for reuse Arrange training programmed and campaigns Create incentives to avoid pollution 153 9. Implementation of the control and fine systems 10. The reuse plans must include how to utilize treated wastewater in wintry seasons and if the effluent quantity drops below demand 11. Co-ordiate the reuse policy with the agriculture policy MEASURES TO BE TAKEN IN ORDER TO MINIMIZE HEALTH RISK Wastewater should be used for irrigation safely and economically. National regulations for the use of treated wastewater stipulate that it is forbidden to grow crops that are to be eaten raw on treated wastewater. In the case of small plants it is very difficult to monitor these individual projects, in this case strict laws should be issued in order to insure safe reuse and minimize the risk of contamination. Monitoring these projects should be coordinated between the ministry of local government and the local council. Public awareness programmers should be adopted in order to reduce the associated health risks. Stakeholder participation should be insured in the planning and implementation of the projects. For these projects to be sustainable and safe, the following guidelines should b adopted: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. It is forbidden to irrigate any crop that can be eaten raw. Drip irrigation or subsurface irrigation should be used to prevent spray contamination All crops to be eaten should be those which grow away from the ground (eg cabbage) Crops with extensive ground cover should be avoided. Priorities should be given to trees especially olive, citrus, jojoba, nut tress, flowers, producing of seedlings etc. Sprinkler and surface irrigation shouldn’t be used Vaccination: all whom will work in the project should be vaccinated Fodder crops should be encouraged. The treatment plant should be efficient if monitored regularly. Public awareness and training of farmers as well as educational leaflet distribution to promote safety measures e.g. wearing boots and gloves, no smoking or eating during working with wastewater, washing hands and face with soap and water after work, cover all exposed wounds with a sterile dressing…..etc Monitoring from local authorities (village council as example) should be implemented. Inspectors from local council can inspect farms easily by just looking at fields. Monitoring the irrigated crops should be at the field level since it is very difficult to monitor the products beyond the farm. Fine systems to be applied and the village council have the right to destroy the entire field that didn’t follow these regulations on the account of the farmers. Industrial crops, table grape as well as fodder crops to be grown Incentives should be given to the active farmers in order to encourage the others using treated wastewater safely for irrigation and reserve fresh water for domestic use. Farmers should contact their doctor in case of: A-persistent stomach aches, diarrhea and bad digestion B-symptoms of worm infection such as itching skin around the bottom or worm traces in excreta. C-chest problem, especially if they come with asthma or lung inflammation D- Regular checkup at least once yearly 154 Table 3. Recommended guidelines by the Palestinian standards Institute (www.psi.gov.ps) Effluent parameter (mg/l) BOD5 COD DO TDS TSS PH NO3-N Fodder irrigation Dry wet Gardens playgrounds Industrial crops Groundwater rechargeable Landscapes 60 200 > 0.5 1500 50 6-9 50 45 150 > 0.5 1500 40 6-9 50 40 150 > 0.5 1200 30 6-9 50 60 200 > 0.5 1500 50 6-9 50 40 150 > 1.0 1500 50 6-9 15 60 200 >0.5 50 50 6-9 50 Contamination of Water Resources Contamination of groundwater aquifers and springs as a result of wastewater percolation is a serious problem in several areas of the West Bank. Pollution of springs has been identified in all district (Table4). Table 4. some major cases of spring pollution by wastewater in the West Bank District Villages where contamination of springs occurred Ram Allah Bethlehem Hebron Jenin Beittin, Al-Janiya, Silwad, Yabroud, Deir Jarir and Abu Shkheidem.Sinjel Aortas, Wade Foqin, Nahhalin and Battir. Beit Ummar, Halhul, Nuba, Kharas, Sa’ir, Kharsa Nothing specific was mentioned. Tulkarm Jaiyus, A’zoun, and all villages who receives water from A’zoun well Nablus Burin, Ijnesiniya, Yatma, Jit, Abalone, Es Sawyer and Odla.Jourish Jericho Aluja,AlQilt Source: ARIJ survey, 2006. The groundwater in the West Bank is vulnerable to pollution from sewage streams and from wastewater disposed of through cesspits. Indicators of pollution appear as nitrate concentration increases in groundwater. Testing of groundwater samples conducted by ARIJ has shown levels of nitrates in some areas of the West Bank to exceed the permissible level (45 mg/l). This increase in nitrate concentration could be as a result of wastewater percolation into the ground or due to the extensive usage of fertilizers. Another problem associated with the percolation of wastewater into the ground is the pollution of rainwater collection cisterns. This source of water is the main source of drinking water in many Palestinian villages. Pollution may occur especially when cisterns are located a few meters from cesspits and in a location below cesspit level. One of the main concerns of the Palestinian municipalities is to limit the pollution of the underground aquifer, the only source of drinking water. Groundwater pollution has been found in Ish Al-Ghorab well in Beit Sahour. Accordingly, the WSSA, in order to protect the groundwater, has ratified a law to connect homes with the new sewage network instead of using cesspits. They have also suggested the introduction of septic tanks to replace cesspits in areas where there is no plan to extend the sewage network. The locally small scale wastewater treatment technology can be successfully used at the household level for wastewater disposal and treatment. The implementation of such units have many positive impacts on the natural environment by 1) improving the management of wastewater 155 treatment and reuse at the household level, 2) protection of surface and groundwater from potential contamination, 3) increase the agricultural area by utilizing the reused water in irrigation of gardens, 4) limit health hazards as a result of illegal discharges of raw sewage. Table 5. Water Consumed and wastewater generation in the West Bank Districts Only from the localities that have water network (2003) Governorate Nablus Ram Allah Jericho Jerusalem Bethlehem Jenin Tubas Tulkarem Qalqilia Salfit Hebron West Bank Total Water Consumed 8683827.4 8949008 2305506.8 6209705 5213582 3557146 657914 5051148 288252 1480331.6 8384567 50280988 Wastewater Generated 4385597 4213317 1131864 2863506 2504936 1764525 325759 2507316 1386579 715790 4108955 25908144 No. of Communities Served By Sewage network 10 8 1 7 8 3 1 5 3 1 6 53 Source: (PWA 2003, Arij 2006) Only 7% of the wastewater in the West Bank is treated, despite the fact that approximately 36.39% of the West Bank population is served by sewage networks (PCBS 2002, Arij 2006). This implies that 93% of the generated wastewater in the West Bank is disposed to the natural environment without treatment. When this wastewater is disposed of without treatment, the ground water and aquifers are polluted. Clear examples of that are: Irtas spring in The Bethlehem district, Sinjel spring in Ramallah district, as well as Alzbeidat ground water well in Jericho district. In addition, flowing raw wastewater is considered a potential source of water born disease. At Al-Aroub refugee camp wastewater is flowing in open channels crossing through Shuyokh Alaroub dawn to the wadi. Health Pressure Since most wastewater is either collected in cesspits problems arise in the wet season when these as well as open channels overflow into the streets. Due to these problems it is worried that conditions at, for example, Al-'Aroub refugee camp and Shyokh Al-'Aroub village, are a source of spreading diseases and insects. With respect to public health, there are frequent outbreaks of diarrhoea in the West Bank. Data indicates that 600 of 2,721 water samples failed to meet WHO bacteriological guidelines for drinking water (Ministry of Health, 2001). Only three of all the samples tested showed no signs of coliform bacteria, and 50 % should not be used for household purposes without treatment. In January 2003, in North Gaza alone, 182 new cases of airborne diseases and 231 of diarrhoea in children under 3 years age were reported–little additional data on diseases exists for Gaza. Nitrate concentrations have been shown to exceed WHO guidelines in 50 % of samples collected from domestic municipal wells (Rishmawi,2004) – causing “blue baby syndrome”. Parasites and helminthes transmitted by mosquitoes as well as skin infections and allergies are also common. The 2002 study by Arabtech Jardanah (consulting firm located in Ramallah) indicated that UNRWA clinic in the Al-'Alaroub refugee camp treats about 10 cases per day related to untreated sewage, with diarrhoea representing 5% of the daily cases treated by the clinic. One of the other major diseases in the study area was Leishmanias; this as a result of insects able to multiply rapidly in 156 stagnant sewage. At Shyoukh Al-'Arroub and Irqantrad those seeking medical assistance often used different private or public sector health centers increasing the difficulty of effective data collection, hence a complete record of the types of diseases is not available. Another example is Alzbeidat village in the Jordan valley (Jericho District), where the people used to depend on a polluted well for their domestic needs. The well was polluted as a result of wastewater seepage from cesspits, the water of which has been the cause of skin rashes among the residents until they stopped using it for drinking purposes. Water is now imported from a nearby settlement which implies additional cost for the villagers. It is also important to mention that the Betir Village, (Bethlehem District) also faces the danger of diseases associated with untreated sewage. The rocky nature of the village’s land rendered the population living at the bottom of the village exposed to sewage contaminated rock surfaces as a direct consequence of sewage seeping from cesspits located at a higher level. Flooding of Wastewater into the Ground Surface Frequent flooding of wastewater from cesspits and open channels, especially during the winter season, is a major environmental and health threat. The accumulation of wastewater in open areas potentially leads to the transmission of infectious disease and the release of foul odor. This scenario is repeated in most Palestinian villages and refugee camps in the West Bank. Flooding of cesspits and open channels is common too, and in some cases one locality may affect another locality as is the case of Al-Jalazone refugee camp and Jifna village in the Ramallah district where Jifna village has been suffering from wastewater overflow from Al-Calzone refugee camp, creating wastewater ponds, and damaging crops and agricultural lands. Due to lack of proper infrastructure, incomplete regulations, standards, and enforcement all types of wastes are released untreated into the environment. As is important to mention, flooding of wastewater from cesspits and open channels is not the only source of pollution to the ground surface. The irresponsible behavior of some citizens, disposing of their sewage by installing a submersible pump in their septic tanks and disposing its effluent freely to the surroundings is another source of pollution to the ground surface. Fig. 1. Betir infected rocky surfaces due to sewage that seeps from cesspits located at higher levels (Source: Arij, 2005) 157 Ground Water Pressure Ground water in wells, springs and volumes of retained water in aquifers, has represented the main source if not the only source of drinking water in the West Bank. The followings are some examples of the ground water pollution due to disposing of wastewater untreated to the natural environment: • Sinjel spring in Ramallah district where the spring is completely polluted with wastewater seeping from the cesspits of the village. • Irtas Spring in Bethlehem district. Where the spring has been polluted by sewage seeping from nearby cesspits. • Alba than (Nablus district) springs and wells; these springs and wells are polluted from Nablus sewage that flows to the east of the town toward Alba than and wadi Alfaro. • Ein Al-Qalt and Aluja spring in the Jordan Valley (Jericho District); these springs have been polluted from sewage that seeps from the neighboring mountainous areas. • Ein Areek Eltahta spring in Ramallah district is another example. Treated Waste Water to be used as Supplementary Irrigation to Enhance Sustainability of Agriculture Treated wastewater can be used for irrigation in west –bank by the followings methods: 1. Reusing of the treated wastewater for irrigation as the only source of irrigation water. This can be in small-scale village scale or region (waster water is collected from several communities) and reused for irrigation 2. Supplementary Irrigation: here in this case treated wastewater can be applied as supplementary irrigation where plants are already planted in the area. 3. Treated wastewater can be reused in small scale systems at the household level (home garden) especially in villages, towns and remote houses. Treated wastewater can be used alone as the only water source, or rainwater can be collected and used either separately or mixed with treated wastewater. 4. Gray wastewater can be treated and recycled for use in toilet flush in order to conserve using fresh water for this purpose Table 6. Al Bireh Pilot Plant (Using Treated Waste Water for Irrigation) Kind of Treatment Irrigation with Fertilizer Irrigation without fertilizer Rain fed with Fertilizer Rain fed without Fertilizer Irrigation with Fertilizer Irrigation without Fertilizer Rain fed with Fertilizer Rain fed without Fertilizer Source: ANERA files 158 Crop Type Wheat 870 Production kg / dunum Seeds Straw 687 1375 656 1332 Wheat 870 537 1187 Wheat 870 500 1031 Wheat Amber 864 1656 Wheat Amber 824 1212 Wheat Amber 600 1000 Wheat Amber 236 336 Home gardens and reusing treated wastewater for irrigation as a mean of enhancing sustainable agriculture. Nowadays there is a move toward small-scale wastewater treatment systems, where small treatment plants conserve one or a group of houses. This plant can treat either black wastewater or gray wastewater. In the case of gray wastewater, the treatment needed is much less than black wastewater and different crops can be irrigated easily and safe. Treating the gray water will be cheaper and securing effluents that meet safe standards will be easier. In Palestine, especially the rural areas, the wastewater from each house or group of houses can be treated, and can be stored and reused in the garden in order to provide food for the people as well as create jobs. Another additional benefit of treating wastewater and its reuse is the reduction in cost with loss of the need to empty them. A reduction in cesspit/septic tank seepage pollution is another benefit. In addition more fresh water will be available for domestic purposes. In this case, the combination of rainwater harvesting from the roof of the house with the treated wastewater and use it for irrigation will play a major role in providing the following: 1. Provide rainwater for irrigation i.e., water free from salts and organic matter. 2. Reduction of wastewater impact on the crop, soil and human being i.e., leaching the salts. 3. Expand the potential for crop selection where in this case most of the crops can be irrigated. Another advantage of home garden (small scale treatment plant) that planting can be practiced in the entire West Bank region (Jordan valley, mountains), as well during the entire year (summer and winter). Table 7. Average production of agricultural crops from the year 1988-1994 according to the statistics of ministry of irrigation Production Planted area Production Consumption Crop 1000 dunam ton/year ton/year % Wheat 170 23,800 300 000 7,9 Barley 140 21000 108 000 19,9 Pease 29 2320 11885 19,5 Alfalfa animal feed 26 15600 1110 000 14 Strategic Options According to the Palestinian Environmental Strategy Wastewater management has been identified as the most urgent element in the Palestinian Environmental Strategy (PES). The strategy calls for establishing an effective wastewater management system that considers the following measures: (Ministry of Environmental Affairs, 2000) • • • • • • • • Rehabilitation of existing wastewater treatment plants and/or construction of new plants based on maximization of capacities in order to minimize the number of plants required Maximizing coverage of households’ connections to the sewer system; Considering alternative collection and disposal measures for areas where the construction of sewage networks is unfeasible Developing regulations for treatment or disposal of sludge that is generated by wastewater treatment plants Enabling an acceptable quality range of influent wastewater, so that treatment plants will be able to treat wastewater effectively Industries have to undertake on-site pre-treatment measures to comply with the treatment plants specifications Developing guidelines and specifications for the wastewater treatment technologies and locations Establishing a cost recovery system. 159 ARIJ EXPERIENCE IN SMALL SCALE PLANTS ARIJ has engaged in implementing 3 units of small scale plants to test their efficiency and performance. It was found that their performance was acceptable as seen below. Furthermore the operation cost is also acceptable Quality of the treated effluent Selected parameters were analyzed to study the efficiency of the small scale wastewater treatment system, and whether if this effluent is suitable for irrigation purposes. These parameters are the Biological Oxygen Demand (BOD5), the Chemical Oxygen Demand (COD), the Total Suspended Solids (TSS), the Ammonium Nitrogen (N-NH4), and the Total Phosphorus (TP). These analyses were carried out in the Biological and Chemical Analysis Center of Al-Quds University. The quality parameters of the effluent are given in Table 8. Table 8. Effluent quality of locally small scale wastewater treatment system Effluent parameters BOD5 COD TS TSS PH N-NH4 TP Concentration (mg/l) Sample1 Sample2 15 15 27 17 653 651 173 171 7.1 7.1 4.6 4.1 5.08 5.23 According to the Palestinian Standards Institution for treated wastewater characteristics (shown in Table 3), the results of effluent parameters show the quality of treated wastewater from a small-scale wastewater treatment unit to be acceptable for garden irrigation purposes with no hazardous impact. However, the TSS concentrations are generally high according by Palestinian standards. Furthermore, by WHO standards, the effluent quality is acceptable for irrigation purposes, except for the TSS which is high, particularly when drip irrigation is used. RESULTS of ARIJ SMALL SCALE PLANTS The results of the small-scale plant installed by ARIJ are encouraging where effluent BOD5 didn’t exceed 23mg/l during the first year of operation. At $0.3usdollar/cubic meter operation costs are reasonable and should be accepted by house owners. CONCLUSION AND RECOMANDATION 1. Current available water is not enough to meet the demand for both domestic and agricultural purposes. 2. Wastewater collection by networks from individual houses and treatment is highly needed in covered by wastewater collection. So small treatment plants can play a major role in covering this gap and preserve the environment 3. Proper planning of wastewater collection and treatment should be done to achieve sustainable wastewater treatment plants. 4. Planning for centralized treatment plants should take into consideration the topography of the area in order to avoid unnecessary pumping. All of the West Bank should be treated as one unit without separation between the districts. 160 5. It seems that implementing waste water collection and treatment for all of the communities is very difficult, furthermore covering the rural areas seems to be impossible due to the huge capital needed as well as due to the permits needed from Israel. 6. Collecting wastewater and treating it at the household level or even at that of the small community will be efficient for its reuse in irrigation 7. Reusing the treated wastewater in the home garden will be economical and highly feasible as a source of water for irrigation. Even on the village scale, waste water can be collected, treated and reused for irrigation 8. Reusing of treated wastewater on a large scale can also be used for irrigation if treatment can be secured. 9. The Palestinian Water Authority as well as ministry of agriculture should plan for using treated wastewater for agricultural purposes at all levels. All of the parties should cooperate in order to make wastewater treatment a success, since any deviation is likely to result in further environmental and heath problems. 10. Palestinian authorities should implant public awareness programs for residents as well as for the local authorities 11. The Palestinian Water Authority should prepare plans to utilize all of the treated waste water for irrigation either on a small or large scale according to the prevailing conditions, e.g. taking into consideration the economic issue, and the suitabliity of the land to be irrigated with treated water. 12. Reusing treated wastewater at the household level will be cheaper since there will be no need for collection and pumping. As well as this treated wastewater will be reused for irrigation at house level REFERENCES Al Beireh Municipality, (1993), Al Beireh, Palestine, Waste Water Treatment Plant Feasibility Study. American near East Refugee Aid, ANERA, Files, Jerusalem, Palestine. Haddad.M.2004 Integrated water and waste management in rural areas in Palestine submitted to international demand water management conference held on the Dead Sea Amman –Jordan. May 30-June 4 2004 F.A.O. (1992) Wastewater Treatment and use in Agriculture, Publication no. 47, Rome – Italy FAO.2002.The Uses of Treated Waste Water in the Forest Plantations in the Near East Region Palestinian Ministry of Agriculture Statistics, 1997. Ramallah – Palestine. Palestinian Water Authority. Palestinian water Law, Ramallah, Palestine. Shuval H., Lambert Y. and Fatal B. (1997). Development of a Risk Assessment Approach for Evaluating Wastewater Reuse Strategy for Agriculture, Water Science Technology Vol. 35, No. 1 Salfeet Municipalities, (1995), Palestine Waste Water Treatment Plant Feasibility Study. Sbeih M. Reuse of Treated Waste Water, Pilot Plants in Al Beireh, 1995, Palestine. W.H.O. (1989) Health Guidelines for the use of wastewater on Agriculture and Aquaculture Technical Report No. 778. W.H.O. Geneva. W.H.O. Geneva. Applied Research Institute, Status of the environment 2006.Beithlehem, Palestine GTZ. (2005). Guidelines of reusing treated waste water in the Jordan Valley. Amman. Jordan W.H.O. (2006) Health Guidelines for the use of wastewater on Agriculture and Aquaculture .W.H.O. Geneva ANERA (2005). American Near East Refugee AID .Jerusalem. Palestine 161 IRRIGATION OF VEGETABLES AND FLOWERS WITH TREATED WASTEWATER * ** ** I. Papadopoulos , D. Chimonidou , P. Polycarpou and S. Savvides Agricultural Research Institute, 1516 Nicosia, Cyprus * Director of Agricultural Research Institute, [email protected] ** Agricultural Research Officers A´, [email protected] / [email protected] *** Agricultural Research Officer, [email protected] *** SUMMARY - Application of recycled water to agricultural land for irrigation could be an alternative water resource for Mediterranean countries facing severe water shortage. Rational use of the nutrients in recycled water could increase crop production and reduce environmental pollution. At the Agricultural Research Institute different studies were conducted to investigate the effect of treated wastewater and N applied on the yield of three field crops and three cut flowers. The first study, included three field experiments with green pepper, eggplants and sudax, irrigated with borehole water or with secondary treated municipal wastewater. Both waters were supplemented 3 3 3 with N applied continuously with the irrigation water at four levels 0 g/m , 50 g/m , 100 g/m and 150 3 g/m . Yield results indicate the superiority of the treated wastewater and its ability to produce high yields with less N fertilizers. The second study included the irrigation with treated wastewater of a) Gerbera jasmesonii and b) for hydroponic culture of Limonium perezii and Antirrhinum. Gerbera jasmesonii was irrigated with secondary treated wastewater, borehole water and fresh water with or without additional fertilization. Results on flower production per plant shown that freshwater produced significantly more flowers per plant than the other water qualities and fertilization had a significant effect on flower production for freshwater irrigated plants but no significant effect on wastewater irrigated plants. Results on Limonium perezii and Antirrhinum in hydroponics, show that both plants irrigated with secondary treated wastewater and treated wastewater from the epuvalisation system were less vigorous and produced significantly less flowers of lower quality than flowers produced from plants irrigated with freshwater with the addition of fertilizer. Results on the effects of fertilizer and water quality on flower weight of gerbera plants indicate that high salt concentration in wastewater can be a limiting factor for the production of sensitive plants such as Gerbera jasmesonii. Mixing of wastewater with freshwater could give good results by lowering the salt concentration of the water and also providing some nutrients to the plants. Key words: Wastewater, irrigation, water reuse, green pepper, eggplants, sudax, nitrogen, Gerbera jasmesonii, Limonium perezii, Antirrhinum. INTRODUCTION In Cyprus and in most Mediterranean countries, the scarcity of water together with the high cost associated with collecting and using the limited surface rainwater for irrigation, have become real constrains for our irrigated agriculture. Because of this, particular emphasis is placed on the water use efficiency and the cultivation of crops with high return per square meter and volume of water i.e. flowers and vegetables (Chimonidou, 2002 and 2003). The irrigated agriculture in semi arid countries like Cyprus demands large amounts of water and faces the serious challenge to increase or at least sustain agricultural production while coping with less and/or lower quality water. Over the years, the severe shortage of water, primarily in the arid and semi-arid regions, has promoted the search for extra sources currently not intensively exploited. Treated wastewater is now being considered and used in many countries throughout the world, as a new additional, renewable and reliable source of water, which can be used for agricultural production. By releasing freshwater sources of potable water supply and other priority uses, treated wastewater reuse makes a contribution to water conservation and expansion of irrigated agriculture, taking on an 163 economic dimension. It also solves disposal problems aimed at protecting the environment and public health and prevents surface water pollution by the direct discharge of pollutants into inland and coastal waters (Papadopoulos and Savvides, 2002, Papadopoulos et.al. 2005). The benefits, potential health risks and environmental impacts resulting from wastewater use for irrigation and the management measures aimed at using wastewater within acceptable levels of risk to the public health and the environment are well documented (WHO, 1973 and 1989, Hespanhol, 1990; Hespanhol and Prost, 1994; FAO, 1992, Jenkins et al., 1994, Asano and Levine,1995, Angelakis et al.,1997). Properly planned use of wastewater can reduce environmental and health related hazards, which have been observed with traditional wastewater disposal. Statistical analysis of rainfall in Cyprus reveals a decreasing trend of rainfall amounts in the last 3 decades. The wastewater generated by the main cities, about 25Mm /year, is collected and used for 3 irrigation after tertiary treatment. About 10 Mm /year is conservatively estimated to be available for agricultural irrigation in the near future allowing irrigated agriculture to be expanded by 8-10% while conserving an equivalent amount of water for other sectors (Papadopoulos 1995). In addition to water benefit to the irrigated land, treated municipal wastewater can provide significant amounts of plant nutrients, especially nitrogen and phosphorous, which can improve the fertility of soils, benefit plant growth, improve crop production and reduce the total requirements of commercial fertilizers needed to be applied, increasing the total economic return to the farmers. However with the treated effluent as an irrigation source, the additional fertilizer N may create conditions of NO3 percolation and pollute groundwater (Papadopoulos and Stylianou, 1987, 1988a,b). The aim of the first study is to present yield results obtained from sudax, eggplant and sweet pepper, irrigated with wastewater and freshwater with the addition of N fertilizer and of the second study, is the effect of water quality and fertilization on flower production of Gerbera jasmesonii (in soil) and Limonium perezii and Antirrhinum (in Hydroponic culture). MATERIALS AND METHODS Experiments of Sudax, Eggplant and Sweet pepper Three separate experiments were carried out from 1998-2001, on sudax (hybrid “Trudan”), eggplants (Solanum melongena) of the variety “Bonica“, and sweet pepper (Capsicum annuum) of the variety “Gedeon“. The treatments included two sources of irrigation water, (borehole and secondary treated wastewater) with four levels of nitrogen, 0, 50, 100 and 150ppm. The field experimental layout for all three experimental plots was a split plot design with four replications with the two sources of water assigned to the main plots and N levels to the subplots. In the sudax experiment each plot consisted of 3 rows 30 m long, spaced 60cm apart and irrigated with 10L drippers spaced 30cm apart on the irrigation line. In the sweet pepper experiment, each plot consisted of three rows 1m apart with 42 plants in each row, having each plant planted 60 cm apart whereas in the eggplant experiment the rows were 80cm apart. Plants of eggplant and sweet pepper were watered by drip irrigation using 10L drippers and in all experiments the amount of water applied was based on Epan evaporation. The field studies were conducted on a calcaric cambisol soil with 20% CaCO3. The secondary treated wastewater used in this experiment is a product of an activated sludge treatment plant from a residential community with no industrial inputs. The quality of the treated wastewater was monitored every week during the investigation period. The analysis included electrical conductivity (ECw), pH, Ca, Mg, Na, K, HCO3, Cl, SO4, NO3-N and B. Nitrate-N was determined by using a specific NO3-N electrode (Kent, EIL model 8006.2). All other analyses were performed according to standard procedures. The average chemical composition of the treated wastewater and borehole freshwater during the irrigation season is given in Table 1. The mean biological oxygen demand (BOD5), the chemical oxygen demand (COD) and the suspended solids (SS) of the treated wastewater were during the irrigation season 76, 45 and 38 mg/lt respectively. 164 Table 1. Chemical composition (ppm) of freshwater and wastewater used for irrigation. ECw pH Ca Mg Na K HCO3 SO4 NO3 Borehole 2.9 mmhos/cm 7.5 36 71 570 9 415 387 Wastewater 3.0 mmhos/cm 7.3 60 52 540 31 482 375 Cl B 75 629 1.2 10 560 0.8 Experiment of Gerbera jasmesonii on soil The experiment on the cultivation of Gerbera jasmesonii was carried out in 2001-2002 using Gerbera of the red variety “testarosa” as the experimental plant, in order to evaluate the effect of four different sources of water with (treatments F1-F5) and without fertilization (treatments W1-W5) on flower production and quality. The sources of water were: a) Secondary treated wastewater, b) Treated wastewater from the epuvalisation system c) Borehole water and d) Fresh water. Analysis of the sources is given in Table 2. Fertilization (treatments F1-F5) consisted of 150ppm N (Ammonium Nitrate), 40ppm P (Urea Phosphate) and 180ppm K (Potassium Nitrate). Once a month 5gr/plant of Fe chelate was applied to all treatments as Gerbera plants are sensitive to iron deficiencies. The plants were grown under 70% shading on ridges 30 cm wide and 40 cm high. The experimental plots were irrigated by drip irrigation using 10L drippers. Water was pumped from the storage tanks near the epuvalisation system with ½ hp electric pumps generated by an electric generator. The experimental design was factorial with six replications. Each replication consisted of 10 randomized plots, each plot being a 6m long row (ridge) with 13 plants 50cm apart. The distance between rows was 120 cm with a central 120 cm wide corridor separating the three replications. Table 2. Chemical analysis of the four sources of water used in the experiment. FRESH WATER pH Conductivity Boron Calcium Magnesium Sodium Potassium Bicarbonate Sulphate Chloride Nitrate SS COD BOD5 7.38 0.92 mmhos/cm 0.37 ppm 50 ppm 52 ppm 103 ppm 2.6 ppm 275 ppm 160 ppm 124 ppm 10 ppm BOREHOLE WATER 7.53 3.03 mmhos/cm 1.15 ppm 36 ppm 71 ppm 570 ppm 9 ppm 415 ppm 387 ppm 629 ppm 10 ppm EPUVALISATION SYSTEM (CHANNEL A) 8.0 2.8 mmhos/cm 0.8 ppm 60 ppm 52 ppm 540 ppm 31 ppm 482 ppm 375 ppm 560 ppm 90 ppm 27 mg/lt 45 mg/lt 80 mg/lt SECODARY TREATED WASTEWATER 8,2 2,6 mmhos/cm 0.8 ppm 60 ppm 52 ppm 540 ppm 31 ppm 482 ppm 375 ppm 560 ppm 100 ppm 31 mg/lt 45 mg/lt 85 mg/lt Greenhouse experiment with flower plants using hydroponics Two flower plants Limonium perezii and Antirrhinum were planted in a new hydroponic system made from Polygal´s plant beds. The plant beds are manufactured from double walled polypropylene sheets and have a drainage system at the base of the channel, which provide better drainage and 165 aeration. Perlite was used as a substrate in the plant beds and plants were irrigated using 4L drippers. The experimental design was factorial with six replications and each replication consisted of four plant beds 2.4m long placed 60cm apart in two rows. In each plant bed six plants from each variety were planted. Both plants were irrigated with: a) untreated secondary treated wastewater, b) treated wastewater from the epualization system c) fresh water with additional fertilizer of 60 ppm N and d) fresh water with additional fertilizer of 120 ppm N. The aim of the experiment was to investigate whether untreated and treated wastewater could be used in hydroponics for flower production without the addition of extra nutrients. RESULTS AND DISCUSSION From the results of yield of eggplant and sweet pepper (Figs 1 and 2) it is demonstrated that wastewater gave better yield and fruit number than freshwater at all nitrogen concentrations and without N application. Without application of N in water, yield increased by 99% in the case of sudax, 65% and 82% in the case of eggplant and sweet pepper irrigated with wastewater compared with treatments irrigated with borehole water. In all cases, application of N in wastewater had no significant effect on yield, and fruit number at all concentrations. a) 600 380 575 360 550 340 525 320 300 500 475 Yield (t/ha) Yield (t/ha) b) 450 425 400 280 260 240 220 200 375 180 350 160 WASTEWATER 325 WASTEW ATER 140 FRESHW ATER 300 FRESHWATER 120 0 50 100 150 0 50 YIELD (t/ha) N applied (ppm) 800 780 760 740 720 700 680 660 640 620 600 580 560 540 520 500 480 460 440 420 400 380 360 340 320 300 100 150 N applie d (ppm) c) W ASTEWATER FRESHWATER 0 50 100 150 N applie d (ppm) Fig. 1. Average yield of a) eggplant, b) sweet pepper and c) sudax as influenced by N applied and water quality. 166 a) 32 00 31 00 30 00 Fruit number ('000 fruits/ha) 29 00 28 00 27 00 26 00 25 00 24 00 23 00 22 00 21 00 W A S TE W A T ER 20 00 FR ES H W A TE R 19 00 18 00 17 00 16 00 0 50 10 0 1 50 N ap p lie d (p p m ) 6 600 b) 6 400 6 200 Fruit number ('000 fruits/ha) 6 000 5 800 5 600 5 400 5 200 5 000 4 800 4 600 4 400 4 200 4 000 W A S T EW A T E R 3 800 F R ES H W A T ER 3 600 3 400 3 200 3 000 0 50 100 15 0 N a p p lie d (p p m ) Fig. 2. Average fruit number of a) eggplant and b) sweet pepper as affected by N applied and water quality. The increase of average yield of sweet pepper from the wastewater-irrigated plots was by 63 % higher compared to the borehole water, 29% for eggplant and by 30% in the case of sudax. In the case of irrigation with borehole water there was no significant difference in yield at N applications above 50ppm in the case of sudax and above 100ppm in the case of sweet pepper. With all crops, higher yield was obtained with the treated wastewater than with the borehole water indicating the superiority of the treated wastewater and the possibility of producing high yields without additional N fertilizers (Papadopoulos and Stylianou, 1987,1988a, 1988b, 1991). It is therefore, imperative that recommendations to the farmers concerning fertilisation should be different for the effluent and fresh water, in order to improve the efficient use of water and of nutrients present in wastewater. This will also minimise the risk of pollution, especially in cases where water table is shallow and pollution by nitrate-N could easily happen (Papadopoulos and Stylianou, 1987, 1988a,b). Properly planned use of wastewater can be of economic importance to crop production as it could substitute for fertilizer application and, therefore, reduce cost of production, which can be an important factor to the agricultural economy of developing countries where fertilizer cost is a major constrain to improve production. On the contrary, results of the productivity of Gerbera jasmesonii (flower production per plant) showed that freshwater produced significantly more flowers per plant than the other water qualities. 167 During the course of the experiment mentha in the epuvalisation system was not fully established from the beginning of the experiment and as it is shown in Table2, of the average water analysis of the four sources of water used in the experiment, there was no significant differences between the secondary treated wastewater and the treated wastewater from the epuvalisation channel A. Therefore there was no significant difference in the flower production and quality between the two treatments (Figs 3 and 4). Fertilization had a significant effect on flower production in the case of freshwater irrigated plants, but no significant effect on wastewater irrigated plants. Plants irrigated with borehole water had a reduction on flower production especially with the addition of fertilizer, when compared with plants irrigated with wastewater. Reduced flower production and quality could be due to the high electrical conductivity and chloride concentration of the borehole water and wastewater as Gerbera plants are sensitive to high salt concentrations (Table2). Results on the effects of fertilizer and water quality on flower weight of gerbera plants indicate that high salt concentration in wastewater can be a limiting factor for the production of sensitive plants such as Gerbera jasmesonii probably due to the slower uptake of water and fertilizer by the plant. Mixing of wastewater with freshwater could give good results by lowering the salt concentration of the water and also providing some nutrients to the plants. 8 FlowerNumber / plant 7 WITH FERTILISER WITHOUT FERTILISER 6 5 4 3 2 1 BOREHOLE WATER FRESH WATER WASTEWATER EPUVAL. WATER Water Treatments 18 17 Fig. 3. Effect of water quality and fertilizer on flower production of Gerbera plants WITH FERTILISER WITHOUT FERTILISER Flower Weight / gr. 16 15 14 13 12 11 10 9 Fig. 4. Effect of water quality and fertilizer on stem weight of Gerbera plants 168 8 BOREHOLE WATER FRESH WATER WASTEWATER Water Treatments EPUVAL. WATER Results of the effect of fertilizer and water quality on flower production of Limonium perezii and Antirrhinum plants showed that both plants irrigated with secondary treated wastewater and treated wastewater from the epuvalisation system were less vigorous and produced significantly less flowers of lower quality than flowers produced from plants irrigated with freshwater with the addition of fertilizer (Figs 5 and 6). Limonium perezii produced significantly higher number of flowers when irrigated with fresh water with the addition of 120 ppm N than when irrigated with fresh water with the addition of 60ppm N, wastewater or treated wastewater from the epuvalisation channel. Antirrhinum on the other hand, produced significantly more flowers when irrigated with fresh water with the addition of 120 or 60 ppm N, than when irrigated with wastewater or treated wastewater from the epuvalisation system (Fig. 5). The quality of the produced flowers in both plants (most pronounced effect on Antirrhinum) followed the same trend with significantly higher stem weight (fresh weight) in the cases of fresh water with the lower level of fertilization 60ppm N (Fig. 6). Plants irrigated with wastewater and treated wastewater from the epuvalisation system showed nitrogen deficiency symptoms indicating that the low flower production was most probably due to the low nitrogen levels in the wastewater during that period (35ppm N in wastewater and 23 ppm N in wastewater treated in the epuvalisation system). Addition of N fertiliser in treated wastewater might be essential when used for irrigation depending on the plant used and level of treatment of effluent. 6 Limonium perezzi 5.5 Number of Flowers / Plant 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 FRESH 120ppm N FRESH 60ppm N WASTEWATER EPUVALISATION Flower Weight / gr. Water Treatments 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Antirrhinum FRESH 120ppm N FRESH 60ppm N WASTEWATER EPUVALISATION Water Treatments Fig. 5. Effect of water quality and fertilizer in flower production and stem weight of Limonium perezii and Antirrhinum plants. 169 Flower Weight / gr. 70 68 66 64 62 60 58 56 54 52 50 48 46 44 42 40 38 36 34 32 30 28 26 24 22 20 Antirrhinum F R E S H 1 20p pm N F R E SH 60ppm N W ASTE W AT ER E P U V A L I S A T IO N W a t e r T r e a t m e n ts 3 2 .8 Number of Flowers / Plant 2 .6 2 .4 2 .2 2 .0 1 .8 1 .6 1 .4 1 .2 1 .0 0 .8 0 .6 0 .4 0 .2 0 F R E SH 120p pm N F R E SH 60p pm N W A S T EW A T E R E P U V A L ISA TIO N W ater T reatm ents Fig. 6. Effect of water quality and fertilizer in flower production and stem weight of Limonium perezii and Antirrhinum plants. CONCLUSION The yield results of eggplant, sweet pepper and sudax, indicate the superiority of the treated wastewater and the possibility of producing high yields without additional N fertilizers. In this case yield might not be the highest but with no additional N, pollution problems are minimized. The plant nutrients load in the wastewater can be an important factor in saving costs of fertilizers needed for crop production. It is therefore advisable that recommendations to the farmers concerning fertilization be different for the effluent and freshwater. On the contrary, Gerbera plants irrigated with wastewater and borehole water, produced less flowers compared to the freshwater irrigated plants probably due to the high electrical conductivity and chloride concentration of both waters, as Gerbera plants are sensitive to high salt concentrations. Plants of Limonium perezii and Antirrhinum irrigated with secondary treated wastewater and treated wastewater from the epuvalisation system, were less vigorous and produced significantly less flowers of lower quality than flowers produced from plants irrigated with freshwater with the addition of fertilizer. However, addition of fertilizer above 60ppm N had a negative effect on flower production. Plants irrigated with wastewater and treated wastewater from the epuvalisation system showed nitrogen deficiency symptoms indicating that the low flower production was most probably due to the low nitrogen levels in the wastewater during that period. Addition of N fertilizer in treated wastewater might be essential when used for irrigation depending on the plant used and level of treatment of effluent. 170 REFERENCES Angelakis, A. N., Asano, t., Marecos do Monte, M. H., (1996). Necessity and basis for establishment of European guidelines for reclaimed wastewater in the Mediterranean region. Wat. Sci. Tech., 33 (10-11), 303-316. Asano, T. and Levine, A.D. (1996). Wastewater reclamation, recycling and reuse: past, present and future. Wat. Sci. Tech., 33(10-11),1-14. Chimonidou Dora, (2002). Country report of Cyprus. In Proceedings of the Regional Experts Meeting on Flowers for the Future. Ismir-Turkey, 8-10 Oct, 2002, p.15-30. Chimonidou Dora (2003). Flowers under protected cultivation with special emphasis on roses and new cut flowers. FAO/AUB First National Conference on Integrated Production and Prodection Management of Greenhouse Crops, p.105-114. FAO, (1992). Wastewater as a source for crop nutrients. Extension publication. Rome, Italy. Hespanhol, I. And A.M.E. Prost. (1994) WHO guidelines and national standards for reuse and water quality. Wat. Res. Vol. 28: 119-124. Hespanhol, I., (1990). Guidelines and integrated measures for public health protection in agricultural reuse systems. J. Wat. SRT-Aqua 39: 227.249. Jenkins, C.R., I. Papadopouloos and Y. Stylianou. (1994). Pathogens and wastewater use for irrigation in Cyprus. In Proceedings “Land and water resources management in the Mediterranean region”. Bari, Italy, 4-8 sept., 1994. Papadopoulos I. and Savvides S., (2002). Optimisation of the use of nitrogen in the treated wastewater reused for irrigation. In proceedings of IWA Regional Symposium on Water Recycling in Mediterranean Region. Iraclio, Greece, 26-29 September 2002. Papadopoulos I., (1995). Present and perspective use of wastewater for irrigation in the nd Mediterranean basin. 2 Intern. Symposium on Wastewater Reclamation and Reuse (A.N. Angelakis et al., Eds.), IAWQ, Iraklio, Greece, October, Vol.2: 735-746. Papadopoulos, I and Y. Stylianou. (1987). Secondary treated urban effluent as a source of N for th trickle-irrigated cotton, sunflower and sudax. In Proceedings of 4 International CIEC Symposium, Braunscheweig, 11-14 May, 1987. Papadopoulos, I and Y. Stylianou. (1988a). Trickle irrigation of cotton with sewage treated effluent. J. Environ. Qual. Vol.17:574-580. Papadopoulos, I and Y. Stylianou. (1988b). Treated effluent as a source of N for trickle irrigated sudax. Plant and Soil 110: 145-148. Papadopoulos, I and Y. Stylianou. (1991). Trickle irrigation of sunflower with municipal wastewater. Agri. Water Manag. 19: 67-75. I. Papadopoulos, Dora Chimonidou, S. Savides and P. Polycarpou , (2005). Optimization of irrigation with treated wastewater on flower cultivations. Proceedings of the ICID Conference 7-11 December 2004, Cairo, Egypt. Options Mediterraneenes, Series B, No. 53 p.227-235. WHO, (1973). Reuse of effluents: Methods of wastewater treatment and health safeguards. A report of WHO Meeting of Experts. Technical Report No. 517. Geneva Switzerland. WHO, (1989). Health guidelines for the use of wastewater in agriculture and aquaculture. Report of a Scientific Group. Technical Report No. 778. 171 RESPONSE OF DURUM WHEAT (Triticum durum Desf.) CULTIVAR ACSAD 1107 TO SEWAGE SLUDGE AMENDMENT UNDER SEMI ARID CLIMATE L. Tamrabet *, H Bouzerzour ** M. Kribaa * and M. Makhlouf *** RNAMS Laboratory, Larbi Ben Mhidi University, Oum El Bouaghi (04000), Algeria ** Biology Dept, Faculty of Sciences, Ferhat Abbas University, Setif (19000), Algeria *** Experimental Farm, Field Crop Institute, Setif (19000), Algeria * SUMMARY - The use of sewage sludge on a large scale and at relatively low rates can contribute to the husbandry of urban wastes. This is interesting since this utilization in agriculture appeared to increase crop production. The results of the present investigation, whose objective was to study the response of a rainfed cereal crop to organic amendment with sewage sludge showed an increase in grain yield and yield component, mainly spike fertility and straw production. 30t/ha of sewage sludge dry matter were as efficient as 66 kg /ha of mineral nitrogen. Key words: Sewage sludge, durum wheat, grain yield, organic mater, mineral fertilization. RESUME - L’utilisation des boues résiduaires sur de grandes étendues à des doses relativement faibles permet d’apporter une solution à terme pour la gestion des déchets urbains. Cette solution est d’autant plus intéressante que les boues utilisées dans le domaine agricole se révèlent bénéfiques en terme d’augmentation de la production. Les résultats de la présente contribution dont l’objectif était d’étudier la réponse d’une culture de céréale conduite en pluviale aux amendements organiques à base de boues résiduaires indique une augmentation du rendement en grains et des composantes du rendement notamment la fertilité de l’épi ainsi que la production de paille. Les apports de boue, pour une moyenne de 30 t de ms/ha, s’avèrent aussi efficace que 66 kg d’azote minéral. Mots clés: Boue résiduaire, blé dur, rendement, matière organique, fertilisation minérale. INTRODUCTION Expansion of urban populations and increased coverage of domestic water supply and sewerage give rise to greater quantities of municipal wastewater. With the current emphasis on environmental health and water pollution issues, there is an increasing awareness of the need to dispose of these wastewaters safely and beneficially. Properly planned use of municipal sewage alleviates surface water pollution problems and also takes advantage of its nutrients contain to grow crops. Sewage sludge can be used to increase crop production, in those situations where the growth conditions due to the unfavorable climate associated to the high production costs don't permit the utilization of chemical fertilizers to overcome cultivated soil fertility problems (Chatha et al., 2002; Pescod, 1992; Ripert et al., 1990). In fact, soils treated with sewage sludge keep longer their relative humidity and their vegetation develops a deeper rooting system as compared to non treated soils (Tester et al., 1982). Sewage sludge liberates progressively nutritive elements they contain and made them available to the plant along the crop cycle. Nitrogen availability is function of the prevailing climatic growth conditions; the amount of applied sludge and the C/N ration (Pescod, 1992; Barbartik, 1985). Soils treated with sewage sludge tended to have a neutral pH and a high phosphorus and organic matter content (Mohammad et al., 2004; Gomez et al., 1984). However sewage sludge are often a source of ground water pollution when their content in high in nitrate (Xanthoulis et al., 1998). They are a source of sol salinity (Tasdilas, 1997), heavy metals pollution (Mohammad et al, 2004; Bozkurt et al., 2003; Aboudrare et al., 1998) and odors nuisance (Sachon, 1995). 173 The present study investigates the response of durum wheat (Triticum durum Desf.) variety Acsad 1107 to the application of sewage sludge under semi arid climate. MATERIALS ET METHODS The experiment was conducted on the experimental site of the Agricultural Farm of the Field Crop Institute of Setif in the Northeastern part of Algeria (5° 24’ 51’’ E longitude and 36° 11’ 21’’ N latitude, and 1000 m altitude) during the 2002/03 crop season. Climate is Mediterranean, characterized by mild rainy winter and dry hot summer with average temperature in summer 24.1°C and 7°C in winter and average annual precipitation of 397.0 mm (AFFCI, 2003). Total amount and distribution of rainfall for the period of the study are presented in (Table 1). The soil is loamy clay and its chemical characteristics are presented in (Table 2). The trial was laid out in a randomized complete blocks design with three replications. Five treatments were compared: a check without application of sludge nor nitrogen fertilization, a treatment without sludge but fertilized with 33 units ha-1 of urea, applied during the tillering stage, and three treatments with respectively 20, 30 et 40 tons dry sludge ha-1. The characteristics of the dry sludge used are reported in (Table 3). The different physico-chemical analyses of the soil and the sludge were carried out at the beginning of the experiment on dry and fine samples (< 2 mm). The determination of the pH and the electrical conductivity were done by Consort C535 Multiparameter on 1:2.5 and 1:5 soil/distilled water respectively, the soil texture by the hydrometer method and the others by standards methods (Chapman and Pratt, 1982). Acsad 1107, a durum (Triticum durum Desf.) genotype, was sown on December 20th 2002 at a 300 seeds m-2 rate on plots whose dimensions were 6 rows x 5 m long x 0.20 m space between rows. Emergence was noted on December 28th 2002. Dry sludge was passed through 10x10 mm mech, and applied onto the experiment at the tillering stage. Heading was noted on May 5th 2003 and the crop was harvested on June 16th 2003. Plant height (PHT) was measured at crop maturity; the number of spikes (SN) and total dry matter (BIOM) produced per m2 of soil were estimated from vegetative samples harvest from Table 1. Precipitations and temperatures at the experimental site of the Agricultural Farm of the Field Crop Institute (Setif, Algeria) during the period of the study 2002/03 Rainfall (mm) September02 October 02 November02 December 02 January 03 February 03 March 03 April 03 May 03 June 03 D1 1.20 6.40 D2 0.30 6.60 D3 2.80 2.90 Total 4.30 15.90 Min 14.67 11.40 Max 26.49 20.63 Mean 20.68 16.01 59.60 52.50 11.80 11.90 29.80 3.00 101.20 67.40 6.29 3.65 12.91 12.18 9.25 7.91 16.40 28.80 71.80 117.00 0.98 6.22 3.80 19.20 15.00 4.20 38.40 3.58 11.63 4.49 0.60 5.80 31.20 37.60 4.84 14.66 9.92 20.02 18.00 38.40 14.80 2.40 20.40 3.40 13.40 0.60 38.22 43.80 59.40 8.30 11.22 17.95 16.96 22.63 30.32 12.63 19.93 24.14 D1, D2, D3 : Decades 1, 2 et 3 of the month. 174 Temperature (°C) Table 2. Characteristics of the soil (0-20cm) used in the experiment at the experimental site of the Agricultural Farm of the Field Crop Institute (Setif, Algeria) Parameters pHH2O EC OM TC Db Hs Hfc Hwp Units - (mS/m) (%) (%) (g/cm3) (%) (%) (%) Mean values 8.1 0.23 1.7 19.45 1.33 51.5 36.5 16.5 Texture Loamy clay EC: Electrical conductivity, OM : Organic Matter, TC : Total Carbone, Db : Bulk density, Hs : Humidity at saturation, Hfc : Humidity at field capacity, Hwp : Humidity at wilting point. Table 3. Characteristics of the sewage sludge originating from the effluents treatment plant of Ain Sfiha (Setif, Algeria). Parameters Units Mean values Humidity pH(H2O) EC TN C TP K C/N % - (mS/cm) % % % % - 80 7.3 2.61 3.30 33.5 5.7 0.5 10.15 EC : Electrical Conductivity , TN : Total Nitrogen, C : Carbone, TP : Total Phosphorus, K : Potassium 1 row x 1m long area. Grain yield (GY) was measured from the combine harvested trial. Thousand kernel-weight (TKW) was estimated from the count and weight of 250 kernels per replicate. The variables number of kernels produced per m2 ( KNM2) , per spike (KS), aerial biomass accumulated at heading (BIOH), vegetative growth rate (VGR), kernel filling rate (KFR), harvest index (HI) and amount of straw produced (STR), have been deduced by calculus using the following formulas: KNM2 = 1000(GY/TKW) (1) Where: GY: grain yield (g m-2) TKW: thousand kernels weigh (g) KS: KNM2 /SN, with KS: Number of kernels per spike SN: Spike number. m-2 BIOH = BIOM- GY (2) Where: BIOM: above ground biomass measured at maturity (g m-2) VGR = BIOH/DHE (3) Where: VGR: Vegetative growth rate (g m-2 day-1) BIOH: above ground biomass accumulated at heading stage (g m-2), DHE: number of calendars days from emergence to heading stage (days). KFR = GY/KFP (4) Where: KFR: rate of filling of the number of kernels produced per m2 (g m-2 days-1), KFP: number of calendar days in the kernel filling period (days). HI = 100 (GY/BIOM) (5) 175 The collected data were subjected to an analysis of variance. Contrast was employed to test the significance of the following treatments effects (1) Check vs N + Sludge, (2) N vs sludge, (3) sludge linear and (4) sludge quadratic (Steel and Torrie, 1980). The relative comparisons between treatments were done according to the following formulas: Amendment effect N + Sludge (%) = 100 [ (XN+S - Xc)/Xc] (6) Where: XN+s: mean of N+ sludge treatments Xx: check mean Sewage sludge effect (%) = 100 [ (XS-XC)/(XN-XT)] (7) Where: XS: mean of sludge treatment XN: mean of N treatment Xc: check mean. RESULTS AND DISCUSSION The analysis of variance showed a significant treatment effect for the whole variables measured but not for the number of spikes (Table 4). The non significant treatment effect for the number of spikes could explained by the fact the amendment (sludge and N) was applied later on, at the tillering stage, when this yield component was partially expressed. The amount of sludge applied remains below the nutriments requirement of the plant since the quadratic effect was not significant for the measured traits. The linear effect of the applied sludge was not significant for the thousand kernel weight, the number of kernels per spike and the harvest index (Table 4). The comparison between the check and amendment (N+S) means indicated that mineral as well as organic fertilization were beneficial to the expression of the measured variables of the crop except the number of spikes produced per unit square of land (Table 5). Table 4. Means squares of the analysis of variance of the measured variables Source dll GY SN KNM2 TKW KS BIOH VGR KFR BIOM HI STR PHT Treatment 4 20939.4** 1067.2ns 3201164** 20.35* 76.55** 66006.7** 4.22** 21.7** 45893.0** 85.46** 61169** 406.9** S+N vs C 1 62489.5** 411.2ns 1848504** 72.6** 225.2** 177055** 11.33** 64.79** 449916** 293.7** 196459** 1316.1** S vs N 1 17398.1** 458.8ns 9054255** 4.84ns 78.8** 39190.7** 2.51** 18.04** 108812** 8.06ns 27749** 164.7** S lin 1 3310.7** 3398.6* 792289** 3.23ns 1.25ns 43146.3** 2.76** 3.43* 70360** 0.43ns 19728** 140.2** S qua 1 559.5ns 0.00ns 11198ns 0.72ns 1.01ns 4634.8ns 0.30ns 0.58ns 1973.9ns 39.6ns 738.3ns 6.72ns error 8 301.2 389.1 156915.8 2.92 1.96 1967.6 0.13 0.31 833.9 8.01 763.6 4.9 C= Check, N = nitrogen, S= Sludge, GY = grain yield (g m-2), SN= number of spikes/m2, KNM2 = number of kernels /m2, TKW = 1000 kernel weight (g), KS= number of kernels/spike, BIOH= above ground biomass -2 -2 -1 -2 accumulated at heading stage (gm ), VGR = vegetative growth rate (g m day ), GFR = filling rate of the KNM -2 -1 -2 (g m day ), BIOM = above ground biomass measured at maturity (g m ), HI = harvest index (%), STR = straw -2 yield (g m ), PHT = plant height (cm); ns,*,** = effect non significant and significant at 5 and 1% probability level respectively. 176 Under the growth conditions of the present experiment, the relative contribution of the amendment (N + S) to the increase in the means of the measured variables ranged from 12% for the thousand kernel weight to 168% for straw yield. The amendment effect was negative for the harvest index which is reduced by 20.0% relatively to the mean expressed by the check treatment. This could be explained by the fact that the nitrogen or the sludge applied had a more pronounced effect on the accumulated above ground biomass than on gain yield (Table 4, Fig. 1). 180 160 140 120 100 % 80 60 40 20 0 -20 GY KNM2 TKW KS BIOH VGR KFR BIOM HI STR PHT Fig. 1. Contribution of the applied amendment (N+ S) to the increase in the mean values of the measured traits relatively to the mean values of the check. Table 5. Mean values of the different treatments SN GY KNM2 TKW KS BIOH VGR KFR BIOM HI STR PHT C 318.9 147.5 3159.2 46.53 9.9 223.3 1.79 4.75 370.8 54.2 169.5 58.7 N+S 305.8 308.9 5933.7 52.03 19.6 494.9 3.96 9.95 803.7 43.2 455.6 82.1 N 316.5 242.9 4769.1 50.93 15.1 395.9 3.17 7.82 638.8 41.7 372.3 75.6 S 302.3 330.9 6321.9 52.40 21.0 527.9 4.22 10.65 858.7 43.6 483.4 84.2 20 278.5 301.8 5879.6 51.5 21.3 459.1 3.67 9.72 760.9 44.9 419.6 80.0 30 302.3 342.0 6479.6 52.8 21.5 495.8 3.97 11.01 837.8 40.6 496.2 83.0 40 326.1 348.7 6606.4 52.9 20.4 628.7 5.03 11.23 977.5 45.4 534.3 89.7 C= Check, N = nitrogen, S= Sludge, GY = grain yield (g m-2), SN= number of spikes/m2, KNM2 = number of 2 kernels /m , TKW = 1000 kernel weight (g), KS= number of kernels/spike, BIOH= above ground biomass accumulated at heading stage (gm-2), VGR = vegetative growth rate (g m-2 day -1), GFR = filling rate of the KNM-2 -2 -1 -2 (g m day ), BIOM = above ground biomass measured at maturity (g m ), HI = harvest index(%), STR = straw yield (g m-2), PHT = plant height (cm). 177 The relative increase in the mean values of the yield component was smaller compared to the increase noted in grain yield. Grain yield increase resulted from the multiplicative effects of the increase obtained in the yield components. The thousand kernel weight was the yield component which was the less sensitive to the amendment effect; because this trait is formed when climatic growth conditions become less favorable. The increase noted in the mean value of straw after application of sludge or mineral nitrogen indicated that organic or mineral amendment induced a better expression of the above ground biomass compared to the grain yield, which had a negative effect on harvest index as explained above. The comparison between organic amendment and mineral fertilization treatments showed that the mean values of these treatments did not differed significantly for the number of spikes, thousand kernel weight and harvest index (Tables 4 and 5). For these traits the effect of sewage sludge application was similar to the effect of nitrogen mineral fertilization. Organic amendment induced a relative increase of 128.1% for plant height and 213.5% for the number of kernels per spike. Grain yield showed a 192.7% increase relatively to the check mean yield (Table 5, Fig. 2). On average application of sewage sludge appeared to be more beneficial for the crop than mineral nitrogen fertilization. The effect of the applied sewage sludge was significant and more apparent on spike fertility, above ground biomass accumulated at heading and maturity, on vegetative growth rate and grain filling rate. These results indicated that applying sewage sludge to cultivated soils induced an increase in crop grain yield and contributed to disposal of and recycling of this waste material (Ripert et al., 1990). The increases noted in grain yield and in the yield associated variables are due to the high concentrations of nitrogen, phosphorus and organic matter of the sewage sludge applied. Bouzerzour et al. (2002) reported that the application of sewage sludge increased leaves dimensions, leaf area index, accumulated above ground dry matter, tillering capacity and plant height of barley (Hordeum vulgare L.) and oat (Avena sativa L.) genotypes, evaluated in pots experiment. They noted also that the response of the measured variables to the applied sewage sludge was linear which corroborated the results of the present study. The maximum amount of 40 t ha-1 of applied sewage sludge did not show any harmful effect on the expression the measured parameters. 220 210 200 190 % 180 170 160 150 140 130 120 GY KNM2 KS BIOH VGR GFR BIOM STR PHT Fig. 2. Relative increase in the mean values of the measured traits due to the effect of applied sewage sludge as % of the mineral nitrogen fertilization effect 178 In the present study yield increase originated from the increase noted in the number of kernels produced per unit square of soil (r GY/KNM-2= 0.98*) and to the number of kernels per spike (rGY/KS = 0.92*) but not from the fertile tillering ability of the crop (r GY/SN =0.21ns). During the course of the experiment the check treatment was somewhat earlier and senesce more rapidly than the amended treatments. Application of sewage sludge acted as a seal, it reduced from the soil evaporation, and helped to keep soil more moist because of its high organic matter content. Sewage sludge is considered as a substrate which is susceptible to contribute to maintain soil organic matter and to improve soil structural stability, cationic exchange and water retention capacities (Gomez et al., 1984). Barbartik et al. (1985) noted that application of sewage sludge during 4 consecutive cropping seasons increased the upper the organic matter content of the upper 15 cm soil horizon from 1.2 to 2.4%. Tester et al. (1982) studied the response of tall fescue (Festuca arundinacea L) to sewage sludge; they observed that soil amendment with sewage sludge improve tall fescue nitrogen nutrition, stimulated root growth and increase forage production comparatively to the non amended check. With ray grass (Lolium perenne L), Guiraud et al. (1977) observed an improvement of nitrogen concentration of tissue of plants grown in sewage sludge amended soils. Cherak (1999) noted an improvement of the tillering capacity of oat (Avena sativa L.) grown under sewage sludge amended soil. According to Sachon (1995) incubated sewage sludge develops aerobic and anaerobic chemical reactions which, in 6 to 7 weeks, reduced the organic matter to the form of compost which is similar to the humus. The mineralization of organic nitrogen is dependent on the C/N ratio, higher this ratio is the lower the mineralization will be (Barbartik et al., 1985; Sachon, 1995). CONCLUSION Use of wastewater in agriculture could be an important consideration when its disposal is being planned in arid and semi-arid regions. Treated sludge can be applied to growing cereal crops without constraint. Land application of raw or treated sewage sludge can reduce significantly the sludge disposal cost component of sewage treatment as well as providing a large part of the nitrogen and phosphorus requirements of many crops. The organic matter in sludge can improve the water retaining capacity and structure of soils, especially when applied in the form of dewatered sludge cake. Sludge application resulted in significantly increased crop yields, attributed to the beneficial effects on soil structure and to the nutrients contain. REFERENCES Aboudrare N., Jellal T., Benchekroun D. and Jemali A. (1998). Wastewater reuse for agricultural purposes in Ouarzazate. Terre et Vie, 26: 7-12. AFFCI (2003) Weather data report. Experimental Farm, Field Crop Institute, Setif , Algeria. Barbartik A., Lawarabnce JR., Sikpra J. and Colacicco D. (1985). Factors affecting the mineralization of nitrogen in sewage sludge applied to soil. Am. J. Soil Sci., 49: 1403-1406. Bozkurt M.A. and Yarilgaç, T. (2003). The effects of sewage sludge applications on the yield, growth, nutrition and heavy metal accumulation in apple trees growing in dry conditions. Turkish Journal of agricultural Forestry, 27: 285-292. Bouzerzour H., Tamrabet L. and Kribaa M. (2002). Response of barley and oat to the wastewater irrigation and to the sludge amendment. Pers. comm. Chapman H.D. and Pratt, P.F. (1982). Methods for analysis of soils, plants and water. Chapman publishres, Riverside, CA. Chatha, T.H. Haya, R. and Latif, I. (2002). Influence of sewage sludge and organic manures application on wheat yield and heavy metal availability. Asian Journal of Plant Sciences, 1(2): 79-81. Cherak L. (1999). Incidence of wastewater reuse on the microflora and the oat behaviour. Master thesis, University of Batna, Algeria. 110 pages. 179 Gomez A., Lineres, M., Tanzin, J. and Solda P. (1984). The study of the effect of addition of the sludge to sandy soils on the quantitative and qualitative evolution of the organic matter. CR. Acad. Sc. Fr. 516-524. Guiraud G., Fardeau JC. and Hetier JM. (1977). Evolution of the soil nitrogen in the presence of the sewage sludge. Pers. Comm. Mohammad, M.J. and Athamneh, B.M. (2004). Changes in Soil Fertility and Plant Uptake of Nutrients and Heavy Metals in Response to Sewage Sludge Application to Calcareous Soils. Journal of Agronomy 3(3): 229-236. Pescod, M.B. (1992). Wastewater treatment and use in agriculture. FAO irrigation and drainage paper N° 47. Rome. Ripert C., Tiercelin JR., Navarot C., Klimo E., Gajarszki G., Cadillon M., Tremea L. and Vermes L. (1990). Agricultural and forestry reuse of the domestic wastewater. Technical report of Cemagref. 79. pp 18. Sachon S. (1995). The sludge of the urban wastewater treatment plants, reuse in agriculture BTI., 21: 14-29. Tester CF., Sikora LJ., Taylor JM. and Parr JF. (1982). N Utilization by tall fescue from sewage sludge, compost amended soils. Agro. J., 74 : 1013-1018. Steel GDS. and Torrie JH. (1980). Principles and procedures of Statistics: a biometrical approach. Editions Mc Graw Hill Book Company, NY. Tasdilas CD. (1997). Impact of wastewater reuse on some soil properties. Pers. Comm. Xanthoulis, D., Kayamanidou M., Choukr-Allah R., El-Hamouri B., Benthayer B., Nejib Rejeb M., Papadopoulous I. and Quelhas Dos Santos J. (1998). Wastewater reuse in irrigation, global approach of the effluents treatment, comparison the different irrigation systems on divers crops and their institutional and organisational aspects. Synthesis of the multilateral research projects on wastewater. Faculty of agronomic sciences, Gembloux. 10 pp. 180 REUSE OF MEMBRANE FILTERED MUNICIPAL WASTEWATER FOR IRRIGATING VEGETABLE CROPS A. Lopez *, A. Pollice *, G. Laera *, A. Lonigro **, P. Rubino ** and R. Passino * * CNR, Istituto di Ricerca Sulle Acque, Viale F. De Blasio 5, 70123 Bari, Italy ** Università di Bari, Dip. Scienza delle Produzioni Vegetali, Via Amendola, 70123 Bari, Italy SUMMARY - In the framework of a nationally relevant project named AQUATEC carried out in the period 2002-2006 and focused on innovative tools for mitigating the water-stress and/or scarcity in southern Italy, a technical scale investigation was performed to test the suitability of membrane filtration for agricultural reuse of municipal wastewater. Membrane filtration was tested at Cerignola (FG) where a test field was also operated and three different crops (processing tomato, fennel and lettuce) were grown in rotation. The experimental period considered in this paper spans between summer 2003 and spring 2005. Technological, water-quality and agronomic aspects were carefully investigated. Throughout the whole investigation the quality of treated wastewater was monitored (chemically and microbiologically) and compared with conventional water pumped from a local freatic well. Both water sources were used in parallel for irrigating two separate plots of the test field. Except for higher Cl-, Na+ and B concentrations, the average chemical quality of tertiary filtered municipal wastewater was comparable with that of conventional well-water. Irrigation with treated wastewater caused an increase of Na+, Ca++ and EC values in the soil during summer periods that, however, were recovered during the following rainy seasons. From the microbial standpoint, unexpectedly, the plot irrigated with well-water resulted more contaminated than that irrigated with treated wastewater. The measured content of heavy metals in vegetables was independent of the water used for irrigation. Crops productivity did not show significant differences between the plot irrigated with treated wastewater and the one watered with well-water. Keywords - Wastewater reuse, membrane filtration, alternative water resources, water scarcity management. RESUME - Dans la structure d'un projet nationalement pertinent, nommé AQUATEC, fait dans la période 2002-2006 et s'est concentré sur les outils innovateurs pour atténuer la stress d'eau et/ou la pénurie en Italie du sud, une enquête a été exécutée à l'échelle technique pour tester la convenance de filtration de la membrane pour la réutilisation agricole d'eau usée. La filtration de la membrane a été testée à Cerignola (FG) où une zone d'essai a aussi été opérée et trois récoltes différentes (tomate traité, fenouil et laitue) ont été grandi en rotation. La période expérimentale considérée dans ce papier a été déroulée entre été 2003 et printemps 2005. La qualité d’eau technologique et les aspects agronomiques ont été enquêtés avec soin. Partout dans l'enquête entière la qualité d'eau de rebut soignée a été dirigée (chimiquement et microbiologiquement) et bien comparé avec les eaux conventionnelles pompées d'un phréatique local. Les deux sources de l'eau ont été utilisées en parallèle pour irriguer deux intrigues séparées de la zone d'essai. À l'exception de la plus haute concentration en Cl-, Na+ et B, la qualité chimique moyenne de l’eau usée de filtration tertiaire était bien comparée avec celle conventionnel. L'irrigation avec eau usée traitée a causé une augmentation de la valeur de Na+, Ca++ et EC dans le sol pendant les périodes estivales qui, cependant, s'est été remises pendant les saisons pluvieuses suivantes. Du point de vue microbien et de façon inattendue, l'intrigue irriguée avec les eaux de puits est plus contaminé que celui irrigué avec les eaux usées traitées. Le contenu mesuré de métaux lourds dans les légumes était indépendant de l'eau utilisée pour l’irrigation. La productivité des récoltes n'a pas montré de différences considérables entre l'intrigue irriguée avec les eaux usées traitées et celui arrosé avec les eaux des puits. Mots-clé - réutilisation de l'Eau usée, filtration de la membrane, ressources de l'eau alternatives, gestion de la pénurie de l'eau. 181 INTRODUCTION In Italy, an overall annual water inflow around 155 billions m3 yields only 52 billions m3 of resources actually utilizable. However, because of the geographically uneven rainfalls distribution, in southern regions such figures drastically decrease as rainfalls are much lower (even 30 % less) than the national average (980 mm/y) (IRSA-CNR, 1999). Furthermore, in such areas, very often, only part (15-20%) of the already scarce water resources is actually available because of the out-of-date local water distribution systems. Accordingly, most of such regions have to face major problems related to water shortage for agriculture and, in some cases, even for drinking purposes. With the aim to tone down water stress in these areas, a national relevant and strategic R&D and Training project whose acronym is AQUATEC has been carried out in five Regions (Campania, Apulia, Sicily, Calabria and Basilicata) in the period 2002-2006. The project was mainly focused on developing and/or testing innovative tools for contributing to mitigate the chronic water-stress and/or scarcity peculiar of these areas. Referring to Apulia, it is a southern east region extended for about 20,000 km2 with 800 km of coasts and about 4,500,000 inhabitants. At national level, it is the region with the lowest rainfall average value (i.e. about 660 mm) and, because of its orography and its hydro-geological subsoil features, its average runoff coefficient value (0.23) is also the lowest (IRSA-CNR, 1999). Nevertheless, the economy of the region, mainly based on two water demanding activities, agriculture and tourism, is ranked as one of the best in the south of the Country. This is possible thanks to the Apulian water aqueduct (AQP), the largest in Europe, which imports water from three bordering regions: Campania, Lucania and Molise. AQP is a complex multi-purposes and multi-reservoirs system with 19,635 km of distribution networks; it serves 4,623,349 inhab. and distributes, net of leakages, 309,416,113 m3 of drinking water (http://www.aqp.it/home.htm). As for the Apulian agricultural sector, it must be pointed out that in spite of the scarce regional rainfalls, most (78.8%) of the Apulian land is used for agricultural purposes (i.e., 15,239 km2 over a total area of 19,332 km2). However, only 23.8 % (i.e., 3,653 km2) of the cultivated area is irrigated. Although such a small portion of irrigated land, in order to satisfy the agricultural water demand, in addition to the resources provided by large irrigation-water distribution consortia, in the region relevant amounts of water are withdrawn from local aquifers as a negative gap of about 700 Mm3 exists (Portoghese et al., 2005). In practice, to fill this gap, it has been estimated that regional farmers have drilled, more or less legally, about 140,000 wells and because of such an extensive groundwater over-exploitation, particularly in coastal areas, a sharp salinity increase, with peaks such high as 20,000 µs/cm, has taken place due to sea water intrusion phenomena (Maggiore et al., 2001). Taking into account that agricultural reuse of municipal wastewater is an appropriate tool for mitigating local scarcity of water resources (Lazarova, 2003) and that in the whole Apulian region about 250 Mm3/y of treated wastewater could be reused for partially filling the above gap, within the AQUATEC project a specific activity has been planned and carried out in Apulia testing the suitability of membrane filtration technology for agricultural reuse of municipal wastewater. At a test field located in the Municipality of Cerignola (FG), three different crops (processing tomato, fennel and lettuce) were grown in rotation. Membrane filtration was chosen as viable technology due to its claimed efficiency for treating wastewaters with variable characteristics and removing pathogenic microrganisms. The main beneficial features of such a technology are the possibility of avoiding chemical disinfection and its toxic by-products as well as maintaining fertilizing species such as ammonia and phosphate ions in treated effluents. This paper just reports the main results recorded during the investigation carried out in Apulia within the AQUATEC project. MATERIALS AND METHODS Membrane filtration pilot plant Wastewater tertiary treatment by membrane filtration was carried out at the pilot scale by a hollow fiber submerged system (Zenon Environmental Inc., Canada). The membrane fibers were assembled 182 in a module (ZeeWeed®) having a total membrane surface of 23.5 m2. The module was plunged into a 1.5 m3 steel tank fed with municipal secondary effluent and was operated out-in, i.e. the permeate was extracted from the internal surface of the fibers by imposing a negative pressure (never exceeding 0.7 bar) to both ends of the module, where the extremities of all fibers were connected. Hollow fibers have an external diameter of about 1.9 mm, internal diameter around 1.0 mm, and nominal (average) pore size of 0.03 µm. Operational cycles included extraction of the permeate (300 sec), and backwash (60 sec). The latter step was carried out by pumping, under positive pressure, a fraction of the permeate inside the fibers to unclog their pores. Coarse bubble aeration was also provided in the filtration tank to increase the shear stress and limit biofilm formation on the external surface of the hollow fibers. Operational parameters such as transmembrane pressure (TMP) and permeate flux (J) were regularly recorded. The pilot plant had a maximum productivity of about 0.7 m3/h and was installed at the municipal wastewater treatment plant of Cerignola, a town of 50,000 PE in South-Eastern Italy. A fraction of the secondary effluent of the full scale plant was sent to the pilot for tertiary filtration, and the permeate was stored into six tanks (5 m3 each). Although each irrigation required about 15 m3 of water, a total stored volume of 30 m3 was always available in order to match the continuous production with the discontinuous demand for irrigation. The test-field was located about 100 m away from the pilot plant and was connected to the storage tanks through a pipeline (Pollice et al., 2004). Experimental field Two-year studies (2003-2004) were carried out to compare the effects on soil and crops of two types of water, tertiary filtered municipal wastewater (“Treated Wastewater”, TW) and conventional water (control) pumped from a freatic well (“Conventional Source”, CS), on three crops in succession. The three crops chosen for the investigation were processing tomato, fennel and lettuce. Processing tomato (Lycopersicon esculentum Mill.) was transplanted in June 2003 in double rows 160 cm apart from each other, realizing a theoretical plant density of 3.1 plants/m2, and was harvested in September 2003. Fennel (Foeniculum vulgare Mill.) was transplanted in October 2003 in single rows, 0.3 m apart from each other, realizing a theoretical plant density of 11.1 plants/m2, and was harvested in April 2004. Lettuce (Lactuca sativa L.) was transplanted in April in single rows, 0.4 m apart from each other, realizing a theoretical plant density of 6.25 plants/m2, and was harvested in July 2004. For all crops, drip irrigation was used by placing the dripping lines between each couple of tomato rows and every other row of fennel and lettuce. The three crops were irrigated when the soil water deficit (SWD) in the root zone was equal to 35% of the total available water (TAW). Irrigation was scheduled based on the evapotranspiration criterion, providing water to the crops when the following conditions were met: n 1Σ (Etc - Re) = 30 mm for tomato, and 25 mm for fennel and lettuce where: n = number of days required to reach soil water deficit limits starting from the last watering; Etc = crop evapotranspiration (mm); Re = rainfall (mm). Evapotranspiration was expressed as follows: Etc = E*Kp*Kc with E = “class A” pan evaporation (mm); Kc = crop coefficient; Kp = pan coefficient (0.8). The experimental field was cultivated according to the methods commonly adopted by the local farmers. 183 Analyses Tertiary filtered wastewater and conventional water samples were collected on every watering and analysed according to standard methods (Eaton et al., 1995). The measured parameters were TSS, COD, N-NH4+, NO3-, P-PO43-, electrical conductivity (ECw), total and faecal coliforms, Escherichia coli and Salmonella. Moreover, metals such as Ca, Mg, Na, K, B, Fe, Mn were monitored in both the filtered effluent and the conventional well water. Soil samples were taken from each plot after every crop cycle, at depths decreasing from 0 to 0.8 m, every 0.2 m. They were analyzed for N, P2O5, K, organic matter (O.M.), pH, electrical conductivity on saturated paste extract (ECe), SAR, alcalinity (as CaCO3), and exchangeable sodium percentage (ESP) according to standard procedures (Sparks, 1996). Microbiological analyses (total and faecal coliforms, Escherichia coli, and Salmonella) were also carried out on soil samples at depths of 0-0.1 m and on tomato fruits, fennel heads and lettuce leaves, according to standard methods (Scharf, 1966; Woomer, 1994). Finally, crops productions were compared and dried samples of the crops were extracted and analysed for their content of heavy metals in order to evaluate the differences due to irrigation with the two water sources. RESULTS AND DISCUSSION Pilot plant performance The operational parameters of the membrane filtration pilot plant are summarized in Table 1. Table 1. Operating parameters of the membrane filtration pilot plant. Parameter Unit Operational value Production (suction) time sec 300 Backwash time sec 60 Feed flowrate L/h 2000 Production (suction) flowrate L/h 300 Backwash flowrate L/h 450 Frequency of chemical cleanings For suction pressure > than 0.6 bar During the considered experimental period, the pilot plant operated discontinuously according to the water demand for irrigation and to the management needs of the filtration system. In particular, the operating pressure of the system tended to increase over time due to the variable quality of the secondary wastewater. This pressure increase reflected the tendency of the membrane surface to foul, and was counteracted by periodical chemical cleaning of the module. This was done every time the operating negative pressure reached 0.6 bar, and consisted in sinking the module in a 200 mg /L NaClO solution for 4-6 hours. The solution was removed from the tank and the module rinsed before re-starting the plant’s operation. Figure 1 shows the net flux of the filtration system (i.e. the net productivity of tertiary filtered wastewater) and the operating pressure over time. In the period between June and November 2003 the plant was operated by imposing higher permeate fluxes, and this resulted in more rapid decrease of membrane permeability (i.e. pressure increase). Chemical cleaning was required more often during this period than in the following ones when lower fluxes (and better influent quality) caused slower increase of the suction pressure (Fig. 1). 350 m3 of the tertiary filtered wastewater produced by the pilot plant were used for irrigation of the first experimental crop (tomato) that was transplanted in June and removed in September 2003. The following experimental period spanned from February to April 2004, when the plant produced about 184 1000 m3 of treated effluent, of which 150 m3 were used for the irrigation of fennel. The last period started in June and ended in July 2004, and 100 m3 of reclaimed wastewater allowed the experimental cultivation of lettuce. The average quality of the tertiary filtered municipal wastewater was comparable with the well water conventionally used for irrigation (Table 2). Chemical, physical and microbial characteristics of the tertiary filtered municipal wastewater and the conventional well water showed similar concentrations except for Cl-, Na+ and B that were higher in the treated wastewater. On the contrary, the microbial pollution resulted higher in the well water. However, both chemical and microbiological parameters of the two water sources were below the regional limits for unrestricted irrigation except for the SAR. The higher salinity in the reclaimed wastewater was attributed to the presence of local preserved food industries, whose effluents partly reached the municipal sewer system. The test field and the crops Irrigation seasonal time-spans of tomato, fennel, and lettuce crops were of 57, 106, and 12 days respectively. The three crops were provided with 11, 4, and 3 waterings respectively (seasonal irrigation volumes 3300, 1000, and 750 m3 ha-1 respectively). Irrigation with tertiary filtered wastewater caused an increase of Na+, Ca++, SAR and EC along the soil profile (0-0.8 m) during summer 2003, when a higher number of waterings was provided. However, lower values were recovered in the soil during the following rainy season (Fig. 2). Soil microbial contamination results show that the plots irrigated with the conventional well water were more polluted than those irrigated with the treated municipal effluent (Fig. 3). Salmonella was never found in either plots. Microbiological analyses performed on crop samples showed that total coliforms were the only indicator found on tomato fruits, fennel heads, and lettuce leaves (Fig. 4). Irrigation with treated wastewater did not affect the productivity of the different crops, although the occasional presence of significant chlorine concentrations caused some effects on the plants. The unexpected occurrence of chlorine in the secondary effluent before chlorination was attributed to occasional management practices at the full scale plant. 12 1,2 net flux pressure 1,0 8 0,8 6 0,6 4 0,4 2 0,2 0 Jun-03 Aug-03 Oct-03 Dec-03 Feb-04 Apr-04 Jun-04 pressure (bar) net flux (L m-2 h-1) 10 0,0 Aug-04 time (days) Fig. 1. Behaviour of the membrane filtration pilot plant over the investigated period in terms of productivity (net flux) and energy/maintenance requirements (trans-membrane pressure). 185 Table 2. Average values of the main physical, chemical and microbial parameters measured, over the research period, in the two types of compared water. Treated Regional Conventional Wastewater Source limits (*) TSS mg/L < d.l. < d.l. 10 COD mgO2/L 43 32 50 mg/L 1.0 0.3 2 N-NH4+ mg/L 9.5 5.8 NO3mg/L 2.3 2.3 10 P-PO4mg/L 329 124 Na+ mg/L 45 44 Ca++ Mg++ mg/L 27 51 mg/L 460 256 500 Clmg/L 30 18 K+ B mg/L 1.0 0.1 2.0 Fe mg/L 0.0 0.0 2.0 Mn mg/L 0.0 0.0 0.2 ECw dS/m 2.4 1.5 3.0 S.A.R. 13 4 10 Total coliforms Cfu/100mL 146 293 Faecal coliforms Cfu/100mL 38 73 Escherichia Coli Cfu/100mL 11 9 10 Salmonellae Cfu/100mL 0 0 0 (*) Limits established by Apulia Region for unrestricted reuse of municipal wastewater in agriculture. Parameter Unit 2,5 140 TW 2,0 ECe (dS/m) 100 1,5 80 60 CS 1,0 40 Rainfall (mm) 120 20 0,5 04/03/03 8 04/29/04 ju l ja n fe b m ar ap r m aj ju n oc t no v de c 10/03/03 07/12/04 TW 140 S.A.R. 7 120 6 100 5 80 60 4 CS 3 40 Rainfall (mm) 0,0 ju l au g se p ap r m ay ju n 0 20 2 0 04/03/03 10/03/03 04/29/04 ju l fe b m ar ap r m aj ju n ja n oc t no v de c ju l au g se p ap r m ay ju n 0 1 07/12/04 Fig. 2. Average values of soil Electrical Conductivity (ECe) and SAR versus time recorded over the research period and compared with rainfall in plots watered with conventional source (CS) and treated wastewater (TW). Histograms represent the rainfall. 186 10000 MPN/g of dry soil 1000 Tomato Tomato Treated Wastewater Conventional Source Tomato 100 Fennel Lettuce 10 Lettuce 1 Fennel Fennel Faecal Coliform Total Coliform Lettuce Tomato Fennel Lettuce Salmonella Escherichia coli Fig. 3. Average values of total and faecal coliforms, Escherichia coli and Salmonella (as MPN/g of dry soil) measured at harvesting time in soil samples from plots watered with conventional source (CS) and treated wastewater (TW). 10000 Treated Wastewater Conventional Source Lettuce MPN/g of marketable yield 1000 Tomato Tomato Tomato 100 Lettuce 10 Fennel Lettuce 1 Total Coliform Fennel Fennel Faecal Coliform Escherichia coli Tomato Fennel Lettuce Salmonella Fig. 4. Average values of total and faecal coliforms, Escherichia coli and Salmonella (as MPN/g of marketable parts of vegetables) measured at harvesting time on tomato fruits, fennel heads and lettuce in plots watered with conventional source (CS) and treated wastewater (TW). 187 The content of heavy metals in the vegetables was observed to be independent of the water source used for irrigation. Higher levels of some specific metals were occasionally measured in the crops irrigated with treated wastewater, but these concentrations were below those considered to cause acute toxicity (Table 3). Table 3. Heavy metals average concentrations in crops irrigated with well water (CS) and treated wastewater (TW). Tomato fruits Fennel heads Lettuce leaves CS CS TW 5 10 Metal Unit CS TW Fe mg/kg 12 13 Al mg/kg 4.0 1.2 Cu mg/kg 0 0 Zn mg/kg 0.4 2.0 9 Pb mg/kg 0 0 Mn mg/kg 0 0 TW Common Toxic range range 30-300 7-75 75 3 4 3-20 25-40 10 6 6 15-150 500-1500 0 0 0 0 2-5 400-200 92 101 90 48 15-150 CONCLUSIONS The main results obtained during a two-year field investigation aimed at evaluating the feasibility of using membrane filtered secondary effluents for irrigating vegetable crops (tomato, fennel, lettuce), were the following: • Except for higher Cl-, Na+ and B concentrations, the tertiary filtered municipal wastewater was comparable with the well water conventionally used for irrigation in terms of average quality. Chemical and microbiological parameters of both water sources were below the local limits fixed for unrestricted irrigation, except for SAR. Wastewater salinity was due to uncontrolled effluent dumping into the sewer from local industries. • Irrigation with tertiary filtered wastewater caused an increase of Na+, Ca++, SAR and EC values along the soil profile when higher volumes of water were provided (in summer), but these values returned to the background level during the rainy season. • From the microbial contamination standpoint, unexpectedly, the plots irrigated with well water resulted more polluted than those irrigated with treated municipal effluent, possibly due to untreated wastewater discharge into the water table that caused groundwater faecal contamination. Also, the only indicator found on the irrigated crops were total coliforms. • The content of heavy metals in the vegetables was independent of the water source. • Irrigation with treated wastewater did not affect crops productivity except when unscheduled spikes of relevant amount of chlorine occurred in the secondary effluent due to operational practices at the full scale plant. REFERENCES Eaton, A.D., Clesceri, L.S. and Greenberg, A.E. (Eds.) (1995). Standard Methods for the Examination of Water and Wastewater. 19th edn, American Public Health Association/American Water Works Association/Water Environment Federation, Washington DC. IRSA-CNR (1999). Un futuro per l’acqua in Italia. Istituto di Ricerca Sulle Acque del Consiglio Nazionale delle Ricerche, Quaderni, n. 109, (in Italian). 188 Lazarova, V. (2003). Drivers and constraints for water reuse development in Europe. In: Proc. of Seminar and Symposium: Wastewater Reclamation and Reuse, LIFE 99/ENG/GR/000590, Thessaloniki (Greece), 13-14 February 2003, 65-78. Maggiore, M., Raspa, G., Sabatelli, L., Santoro, D., Santoro, O. and Vurro, M. (2001). Monitoring of seawater intrusion in a karst aquifer (Apulia - southern Italy). In: Proc. of the 1st Int. Conf. on Saltwater Intrusion and Coastal Aquifers - Monitoring, Modeling, and Management. Essaouira (Morocco), 23–25 April 2001. Pollice, A., Lopez, A., Laera, G., Rubino, P. and Lonigro, A. (2004). Tertiary filtered municipal wastewater as alternative water source in agriculture: A field investigation in Southern Italy. Sci Tot. Env., 324, 201-210. Portoghese, I., Uricchio, V. and Vurro, M. (2005). A GIS tool for hydrogeological water balance evaluation on a regional scale in semi-arid environments. Computers & Geosciences, 31, 1, 15-27. Scharf, J.M. (Ed.) (1966). Recommended methods for the microbiological examination of foods. APHA, 2nd Edition, New York. Sparks, D.L. (Ed.) (1996). Methods of soil analysis. Part 3: Chemical Methods. Soil Science Society of America Inc., Madison WI. Woomer, P.L. (1994). Microbiological and biochemical properties. In: Methods of soil analysis. Part 2. R.W. Weaver et al., (Eds.), Soil Science Society of America Inc., Madison WI. 189 USE OF SANDS OF THE DUNES LIKE BIOFILTER IN THE PURIFICATION OF WASTE WATER OF THE TOWN OF OUARGLA (ALGERIA) F. Ammour * and M. Messahel** * Chargée de Cours à l’Ecole Nationale Supérieure de l'Hydraulique (ENSH) tel / fax : 00 213 25399446 Email: [email protected] ** Professor Ecole Nationale Supérieure de l'Hydraulique (ENSH), Member of the Board of World Water Council, Member of French Water Academy Tel : 00 213 63051329 / fax : 00 213 25399446 Email: [email protected] SUMMARY - In Algeria, on the 50 stations of purification carried out, nearly two third are out of order and the 15 stations, which are operational, encounter problems. Their operation is seldom in conformity with the posted performances. This established fact shows the gravity of the situation when it is known that more than 700 HM3 of wastewater are evacuated annually. Like the other towns of the country, the town of Ouargla (southern Algerian) knows serious problems of cleansing in particular since that the station of purification is out of order in 1980. The alarming situation of the network of cleansing of the Ouargla town put in the obligation the authorities to create several outlets around the city. However, the rejection of urban effluents without any preliminary treatment it accentuated the enhancement and the contamination of the water table on one hand and on the other hand it generated the degradation of the closer palm plantations. This Oasis knows today a catastrophic ecological situation, which could be the origin of many epidemics. Facing to cleansing and management of purification stations problems, it’s recommended to involve other techniques of purification less expensive and simpler to manage in order to protect the public health and to safeguard the receiving backgrounds. The use of a local material, such as the sand of the dunes, as biological filter is a promising technique for the purification of the water used in the Algerian south. Among many parameters, which condition the purification capacity of those natural techniques it’s included: their physicochemical characteristics, the quality of water to be treated and the speed of filtration. This study made it possible on one hand to determine of the physicochemical characteristics of sand’s dunes (structure, texture and chemical composition) and to put forward their filtering capacity and on another hand to evaluate the purification performances of the designed prototype. Key words: wastewater, Ouargla in Algeria, treatment and techniques of purification, biological filter INTRODUCTION In the town of Ouargla, the discharges of wastewater in an anarchistic way and without treatment, contribute considerably to the contamination of the ground water and the increase in its ascent. In addition, the state of degradation and out datedness of the station of purification is such as any rehabilitation is not economically possible. Thus the recourse to other techniques such as biological filtration, by using a local material, offers a very promising alternative for the cleansing in the area. SAND FILTERS The sand filters are natural environments, which can be used as mass filter in the purification of wastewater, by ensuring a double role: retention of MES and fixing of the biomass, which develops around the grains. 191 The choice of a filter support rests on the following criteria: - Important specific Surface, favorable to the bacterial development. - The granular support must be siliceous, and stable, at weak soluble matter rate. - The granulometry must be selected in order to provide a sufficient surface to the development of the bio-film and to avoid the too fast filling of the filter. BIOFILTRATION The biological filtration of the wastewater, on granular support and at low speed became a particularly gravitational process of purification. In addition to the mechanical retention of MES, this technique allows the biological breakdown of organic, phosphorated and nitrogenized pollution. On the microbiological level slow filtration constitutes a stage of disinfections, which moreover has the advantage of retaining well the protozoa and the flagellate unicellular, which can resist disinfections by chemical agents. In this process, one attends the development of a biological membrane around the sand grains, in which microscopic algae, bacteria and zooplankton are lodged. They are extra cellular polymers, synthesized by the micro-organisms, which play the part of coagulant. MATERIAL AND METHODS Choice of the filter background On the basis of a preliminary study, carried out on several grounds of the area it arises that: 1. The grounds of the palm plantation have a muddy sandy texture. These grounds have a good permeability and are slightly alkaline. As for salinity, it is very variable in space and the electric conductivity of the extract of the paste of ground varies between 0,60 and 15,43 mS/cm. Let us note that salinity is lower than the average for the majority of the intake points, however, 12% of the analyzed samples have a relatively strong salinity, this is due primarily to the bad drainage, leading to stagnations of water in the low areas, which receive the excess of irrigation water from high zones. 2. For sands of dune and rude sands, we can say that they are grounds with fine sand textures and rude sands, alkaline with a very low salinity and a soluble matter rate which is also weak; these two grounds which are primarily made up by quartz have a rate exceeding 87% of their composition. Sand of dunes and rude sands show favorable characteristics as filtering backgrounds. The results of the qualitative analysis of these two supports are consigned in tables 1 and 2 and fig.1. Table 1. Physical analysis of the soil point of sample Permeability K (cm/h) Density in (kg/l) The coefficient of uniformity The representative diameter Mekhadma 15.29 – 42.89 1.57 – 1.60 1.70 – 1.74 - Ksar 3.52 – 30.80 1.40 – 1.70 1.68 – 1.72 - Ain Beida 7.16 – 81.13 1.31 – 1.60 2.22 – 2.40 - Rouissat 6.28 – 18.49 1.45 – 1.60 1.80 – 1.88 - Sand dune Ain Beida 7.2 – 12.8 1.56 – 1.60 1.69 0.18 Rude sand Ain Beida 78.0 1.60 – 1.62 2.40 0.25 Ground Ground of Palm plantation 192 Table 2.Chemical analysis of the soil Sampling point pH EC (mS/cm) Insoluble (%) CaCO3(%) Mekhadma 8,16 – 6,23 1,45 – 6,00 86,2 – 84,0 0.03 – 0.16 Ksar 7,53 – 6,27 2,12 –15,43 85,2 – 80,25 0.03 – 0.18 Ain Beida 7,96 – 6,12 0,60 – 5,92 83,2 – 78,9 0.13 – 0.46 Rouissat 7,77 – 6.25 2,59 –11,12 80,2 – 79,0 0.13 – 0.24 Sand dune Ain Beida 8,53 0,52 87,94 0.87 Coarse sand Ain Beida 7,80 0,82 94,65 0.87 Ground Ground of Palm plantation The curves of the granulometric analysis, corresponding to the three types of grounds (sand of the palm plantation, sands dunes and rude sands), are represented in fig. 1. % 100 90 80 Sable grossier 70 60 Sable de dune Sable de la palmerie 50 40 30 20 10 0 10 10 1 5 2 0 .1 1 ,4 0 0 .01 0,2 0,1 0,08 Fig. 1. Granulometric analysis of soils of the area of Ouargla For our study we chose the sand of the dunes, which in addition to its availability, presents very favorable characteristics for its use as filters: its permeability is 7.2 to 12 cm/H, its salinity is very low (electric conductivity is 0.52 mS/cm), the rate of the insoluble matters is approximately 87% (quartz compound primarily) and its organic matter is very low (less than 1%). The granulometric analysis show that it is about a very uniform ground (the dimension of the aggregates varies between 0.3 and 2 mm). Experimental device With an aim of studying the performances of sands of the dunes in purification of pre-treated wastewater, we set up an experimental device consisting of: 1. A water container and flow regulator having a volume of 250 ml. 2. A Plexiglas septic tank, which ensures the anaerobic pre-treatment with the following dimensions: L1 = 250 mm, L2 = 125 mm H = 165 mm h1=79 mm and H2 =40 mm (Fig. 2). 193 3. A column of PVC filtration of 90 cm height and 24.2 cm in diameter filled from bottom upwards by a gravel layer of 10 cm and a dune sand layer of 70 cm height. It is posed on an elevated steel support of 25 cm to allow the recovery of filtered water. 4. A water supply system made up of four pipes in the form of a cross provided with nine small slits (ф=1.4mm) in order to allow the water supply of the filter in a homogeneous way. The rate of water supply of the filter is 2.6 l/day. During this study (138 days), we followed the purification performances of each work and determined the total output. CROSS SIGHT IN PLAN H2 h1 H L1 L2 Fig. 2. Dimensions of a septic tank RESULTS AND DISCUSSION After four days of operation (lasted of maturation of the filter) we carried out analyses of raw water, pretreated water (entry of the filter) and water filtered (exit of the filter) at various periods. The results obtained are gathered in Tables 3, 4 and 5. We note an increase in salinity at the exit of the septic tank, which could be attributed to the phenomena of re-releasing. On the outlet side of the filter, the increase in salinity is very important during the first five days, which could be explained by the scrubbing of the salts contained in sand. This increase is stabilized and become less important for the other sampling campaigns. The evolution of the pH on the outlet side of the filter shows a light fall during the first 4 samples then increases for all the other samples. This is explained by a more intense algal development, therefore a strong consumption of CO2, which results in a rise in the pH. The degradation of the organic matter was illustrated by the decrease rates of the DBO5 and the DOC in septic tank. The sand filter and all the installation allowed us to release the following observations: • The reduction in the DBO5 was remarkable; it reaches a best performance in the septic tank after 38 days. • The output knew stabilization with a value exceeding 50 %. The temperature of the study area and the quality of wastewater justifies this increase in the output. • After filtration the rate of abatement varies from 47 to 88.5 % and reached its maximum after 65 days. • The purification performances of the installation exceeds 62%, with a maximum of 97%, at the end of 65 days of operation. The abatements obtained on the DOC were also very interesting: with a range varying from 24.3% to 75.6%, for the septic tank, 55.8% to 89.3% for the filter and 69.6% to 96.2% for all the installation. 194 The outputs obtained are very encouraging and seem justified by the temperature of the area and the quality of wastewater. Table 3. Physicochemical parameters’ analysis Number of days T °C N° Dates 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 10.08.99 17.08.99 29.08.99 05.09.99 12.09.99 19.09.99 26.09.99 09.10.99 17.10.99 30.10.99 13.11.99 20.11.99 29.11.99 04.12.99 12.12.99 21.12.99 5 12 24 31 38 45 52 65 72 86 100 107 116 121 129 138 30 33 32 30 30 29 27 26 28 26 25 23 19 18 20 16 pH Raw water 7.48 7.11 7.37 7.43 6.31 7.42 7.44 6.93 7.23 7.11 6.44 6.81 7.22 6.88 7.38 6.72 EC (mS/cm) Raw Pretreated Filtered water water water 7.80 7.50 7.77 7.93 7.72 7.91 8.00 7.80 7.50 7.40 6.71 7.31 7.43 6.99 7.30 7.38 8.07 7.42 7.65 7.44 7.76 8.10 7.98 8.10 8.21 8.10 8.14 8.16 8.31 8.36 8.34 8.30 2.60 2.80 2.70 2.80 2.70 2.70 2.80 2.70 2.70 2.60 2.50 2.70 2.30 2.80 2.60 2.50 Pretreated Filtered water water 5.40 4.30 3.00 3.10 3.10 2.80 2.90 2.70 2.70 2.70 2.80 2.80 2.30 2.60 2.70 2.60 13.40 5.20 4.20 3.90 4.00 3.80 3.80 3.60 3.40 3.30 3.30 3.60 3.20 3.30 3.40 3.10 Table 4. Results of analysis of the DBO5 N° Number of days 1 2 3 4 5 6 7 8 9 10 11 12 13 14 5 12 24 31 38 45 52 65 86 100 116 121 129 138 Raw water 430.00 450.00 410.00 330.00 580.00 460.00 260.00 500.00 580.00 580.00 480.00 260.00 400.00 300.00 DBO5 Mg/L Pretreated water 360.00 320.00 240.00 180.00 160.00 140.00 70.00 130.00 260.00 270.00 220.00 110.00 180.00 140.00 Filtered water 160.00 170.00 120.00 80.00 40.00 30.00 15.00 15.00 50.00 65.00 60.00 30.00 55.00 45.00 Septic tank Output 16.28 28.89 41.46 45.45 72.41 69.57 73.08 74.00 55.17 53.45 54.17 57.69 55.00 53.33 Output % Filtration Output 55.56 46.88 50.00 55.56 75.00 78.57 78.57 88.46 80.77 75.93 72.73 72.73 69.44 67.86 Total output 62.79 62.22 70.73 75.76 93.10 93.48 94.23 97.00 91.38 88.79 87.50 88.46 86.25 85.00 195 Table 5.Results of analysis of the DCO Number of days 1 2 3 4 5 6 7 9 10 11 12 13 14 15 16 17 5 12 24 31 38 45 52 65 72 86 100 107 116 121 129 138 Rendement N° Rough water 826.00 1200.00 1104.00 768.00 998.00 1286.00 739.00 989.00 952.00 749.00 768.00 624.00 1536.00 634.00 1498.00 1382.00 DCO Mg/L Pretreated water 538.00 826.00 836.00 442.00 394.00 538.00 259.00 355.00 307.00 346.00 365.00 260.00 614.40 211.00 365.00 461.00 Filtered water 230.00 365.00 288.00 154.00 67.00 86.00 29.00 38.00 58.00 86.00 106.00 77.00 192.00 76.80 144.00 154.00 Septic tank Output 34.87 31.17 24.28 42.45 60.52 58.16 64.95 64.11 67.75 53.81 52.47 58.33 60.00 66.72 75.63 66.64 Outputs % Filtration Output 57.25 55.81 65.55 65.16 82.99 84.01 88.80 89.30 81.11 75.14 70.96 70.38 68.75 63.60 60.55 66.59 Total output 72.15 69.58 73.91 79.95 93.29 93.31 96.08 96.16 93.91 88.52 86.20 87.66 87.50 87.89 90.39 88.86 1 2 0 ,0 0 1 0 0 ,0 0 8 0 ,0 0 6 0 ,0 0 4 0 ,0 0 2 0 ,0 0 0 ,0 0 0 50 100 150 Jo u rs Rendement F o s s e S é p t iq u e Rendement f ilt r a t io n Rendement g lo b a le Fig. 3. Evolution of the abatement of the DBO5 according to the time at the exit of each work. 196 Rendement 1 2 0,0 0 1 0 0,0 0 8 0,0 0 6 0,0 0 4 0,0 0 2 0,0 0 Re n d e me n t Fo s s e S é p tiq u e 0,0 0 0 50 100 1 50 Re n d e me n t Filtr a tio n Jo u r s Re n d e me n t g lo b a l Fig. 4. Evolution of the abatement of the DOC according to the time at the exit of each work. CONCLUSION It comes out from this study that the use of sands of dune makes it possible to solve the problem of the water used without recourse to very expensive techniques, which require very important means of management. The physicochemical and granulometric characterization showed that they are very uniform grounds, with sandy texture, primarily of quartz; they are not very saline and at weak rate of limestone and organic matter. Results obtained on the abatement of the DBO5 and DOC show the effectiveness of this technique in the degradation of the organic matter. However, to justify the choice of this technique, it is necessary to carry out an experimental site to reduce the errors of scale and to take into account the other parameters of pollution that was not studied in this work (MES, nitrogenized, phosphorated Pollution and bacteriological quality). REFERENCES Adoun, M.S. (1988). Les procédés d’alimentation en eau et d’assainissement urbain. Maison Errate universitaire, Caire, Egypte (en Arabe). CNERIB, (1993). Centre national d’étude et de recherche intégrées du bâtiment. Assainissement autonome et semi collectif. Edile inf, (1996). Bulletin international de l’eau et de l’environnement N°11. Gougoussi, C. (1979). Assainissement individuel et aptitude du sol à l’élimination et à l’épuration des effluents domestiques. Thèse 3éme cycle, Institut National Polytechnique de Lorraine ; Hadjar, S. (1994). Traitement des eaux potables Haleb SERIE (en Arabe). Memonto technique de l’eau ; Degrement ; 1989 Normalisation française. Mise en œuvre des dispositifs d’assainissement autonome ; AFNOR ; 1992. OMS (1984). Guide pratique pour l’eau et l’assainissement rurale et suburbain, Copenhague 197 SALMONELLA TRANSPORT AND PERSISTENCE IN SOIL AND PLANT IRRIGATED WITH ARTIFICIALLY INOCULATED RECLAIMED WATER: CLIMATIC EFFECTS M.P. Palacios *, P. Lupiola ** F. Fernandez-Vera ***, V. Mendoza * and M.T. Tejedor ** *Agronomía Fac Veterinaria. Universidad de Las Palmas de Gran Canaria [email protected] **Microbiología. Fac Veterinaria. ULPGC. 35416 Autovia Las Palmas Arucas km 6.5 ***Granja Agrícola Experimental Cabildo de Gran Canaria 35416 Autovia Las Palmas Arucas km 6.5 SUMMARY - The acceptability of reclaimed water to replace other resources for irrigation is dependent on whether the health risk and environmental impacts entailed are acceptable or not. Secondary effluent chlorination is extended but there are incidences in which Salmonella survive contaminating reclaimed water ponds. Specific site conditions influence pathogens existence and persistence. The aim of the experiments was to increase the scientific information on the climatic and soil effects on pathogens transport and survive under agricultural conditions. Results from three experiments are presented here. Five pots were irrigated using a secondary effluent artificially inoculated with Salmonella. To study the effect of competence with soil bacteria, plates with sterilized soil were also tested. Radiation effect was also studied by blocking UV light. Stems and leaves, three different soil depths (surface, 0.15 and 0.45 m) and plates were sampled. As result of the radiation effect, less bacterial counts on plant were obtained during the day. But during the night Salmonella was able to re-grow, depending on the nocturnal temperatures. After 3 weeks in the field, Salmonella was still detected in plant samples. Radiation caused Salmonella death in soil samples in spring while natural soil bacteria competence was the main factor affecting in autumn. Soil was able to filtrate Salmonella, but preferential flux transported bacteria to 0.45m depth, surviving 3 weeks. Soil physical properties, irrigation system and water management will have an effect on the sanitary risk associated to reclaimed water irrigation. In this sense, SDI must be considered as the safest irrigation method. Key word: Salmonella, survival, radiation, reclaimed water, soil RESUME - L’acceptabilité des eaux dépurées sur d’autres sources d’eau pour l’irrigation dépend de l’impact sur l’environnement et des risques sanitaires. En ce qui concerne ces derniers, les conditions spécifiques du site de réutilisation influence l’existence et persistance des pathogènes, l’information de la littérature scientifique à ce sujet étant contradictoire. La chloration lors du traitement de l’eau est très étendue mais il y a des évidences sur la survivance de Salmonella. L’objectif de ce travail est de contribuer à la connaissance de l’effet du climat et des sols sur la transport et la survivance de Salmonella dans des conditions de terrain en culture. On présente les résultats de trois expériences. Cinq pots semés de Medicago sativa furent irrigués avec un effluent secondaire inoculé de Salmonella. Les paramètres climatiques furent registrés avec une station climatique automatique. Les tiges et les feuilles, ainsi que les sols à trois profondeurs (surface, 0.15 et 0.45 m) furent échantillonnés. Comme résultat de la radiation, le nombre de bactéries décru pendant le jour, tandis que pendant la nuit une re-croissance se produit, spécialement dans l’expérience du printemps. Après trois semaines sur le terrain, on pouvait détecter la Salmonella dans les échantillons végétaux. La radiation semble être la cause de la mort de Salmonella dans les sols au printemps tandis que la compétence biotique pourrait être le facteur principal en automne. Le sol est capable de filtrer la Salmonella, mais à travers le flux préférentiel, elle peut atteindre le sous-sol (0.45 m de profondeur) où elle peut survivre au moins trois semaines. Mots Clés: Salmonella, survivance, radiation, eau dépurée, sol 199 INTRODUCTION Municipal reclaimed water, as a non-conventional resource, can increase the sustainability of agricultural production mainly in arid and semiarid countries. Specific site conditions influence pathogens existence and persistence in agricultural lands (Guan and Holley, 2003). Water and soil characteristics, irrigation systems and water management (Sivapalasingam, 2003), crops, animal and human exposure affect so much the risk associated with water reuse that no quality standards are universally accepted (WHO, 1989 and 2000, Pescod, 1992, Westcot, 1997, Blumenthal et al., 2000, ANZECC, 2000, Carr et al., 2004, USEPA, 2004) and sometimes contradictory information in the scientific literature is found based on the proposed criteria: risk assessment or sustainability criteria (Jensen et al., 2001). Finally, the climatic effect on pathogen persistence or attenuation must be also considered. Thus, acceptability of reclaimed water to replace other water resources for irrigation is highly dependent on whether the health risk and environmental impacts entailed (Pedersen et al., 2005) are acceptable or not (Angelakis et al., 1999). There is a lack of regulatory standards in Europe regarding reclaimed or “regenerated” water reuse. In fact, nowadays in Spain there is not reuse regulations at all. Total count and species of microorganisms founded in wastewater widely varies due to climate conditions, season, population sanitary habits and diseases incidence. The use of many bacteria indicators is extended, but only limited species of them are pathogens. Salmonella is one of the pathogenic bacteria most frequently associated with water caused illness (Fernández-Crehuet y Espigares, 1995; Fett and Cooke, 2003; Brooks et al., 2003; Estrada-Garcia et al., 2004). Although chlorination is widely extended, there are situations in which coli forms, Salmonella and other heterotrophic bacteria are able to survive (Al-Nakshabandi et al., 1997; Snelling et al., 2006) especially in rural communities with low cost water treatment plants (Hernandez Moreno and Palacios, 2006). In this sense, Tejedor et al. (1998) detected the rare presence of Salmonella in chlorinated reclaimed water in agricultural field lands. That presence coincided with seldom high DBO5 values of the secondary effluent measured in the reclaimed water treatment plant. Salmonella lives in gastrointestinal habitat. Thus, it is widely accepted that it has a limited survival period in environmental conditions. Despite of this, high nutrient contents of agricultural soils (especially when irrigated using reclaimed water) and favourable temperature and humidity conditions (frequent in irrigated lands from semiarid countries) have been mentioned as a suitable environment for pathogenic bacteria (Byappanahalli and Fujioka, 1998). In this sense, pathogenic bacteria have been previously cited as able to persist in water, soils and on crops (Batarsseh, et al. 1989a,b, Hassen et al., 1996), agreeing with our results showing that Salmonella is able to survive in reclaimed water ponds for periods longer than one month (Tejedor-Junco et al., 2005) in subtropical climates. The establishment of Macaronesian quality guidelines for reclaimed water (RW) reuse envisages: (i) Developing a single set of guidelines and criteria that are appropriate for Macaronesia and that are based on a consensus of Macaronesia expert and other role players in water quality, and (ii) Adapting national/international guidelines in the light of local research and experience (Palacios and Hernandez- Moreno, 2005). Thus, the aim of this experiment was to increase the scientific information on the climatic and soil effects on pathogen transport and survive under agricultural field conditions, in order to improve local knowledge and to establish the best reclaimed water management practices from health, environmental and economical point of view. MATERIALS AND METHODS Analysing the results of two previous assays that were carried out during autumn and spring (Palacios et al., 2001) we decided to conduct a third experiment. In this experiment we increased the frequency of sampling to demonstrate our hypothesis. Thus, the results from this third experiment carried out during the following autumn are presented here. Detailed material and methods are presented in mentioned paper. Five pots (0.8 m height and 0.9 m in diameter) were placed in the experimental field, filled with local soil 9 months before the first experiment and seeded with Medicago sativa. Two pots were irrigated using a secondary effluent in each experiment: one artificially inoculated and the second one without Salmonella (control). One control pot from the first experiment was reused for the third. Main soil characteristics were: clay soil (47% of expansive clay), 1.1% of organic matter, 1.8 dS/m of electrical conductivity, 38 and 83 mg/kg of nitrates and Olsen phosphorous and 4.36 me/100 g of potassium. An Automatic Weather Station recorded climatic 200 parameters. The reclaimed water were artificially inoculated with a known Salmonella biotype and serotype with (124±8)·103 (first experiment) (565±85)·103 (second) and (412±73)·103 (third) cfu·mL-1. Reclaimed water samples were collected in sterilized bottles before inoculation and were analysed for Salmonella presence. Soil and plant samples were also analysed before each experiment. Composite plot soil samples were taken from soil surface, 0.15m and 0.45m depth, after different periods in each experiment: 2, 7 and 12 days after irrigation (first experiment); 22, 46, 166, 310 and 358 hours after irrigation (second experiment) and every two hours from sunrise to sundown during 3 days, 10 and 20 days after irrigation from the soil surface. For 0.15 and 0.45m soil a sample was taken 1, 2, 3, 10 and 20 days before irrigation (third experiment). Open plates (filled with sterilized soil) and ultra violet radiation isolated plates (filled with non sterilized soil) were sited on the two plots surface in the second and third experiments. Every plate was irrigated using the same quality of water than used to irrigate each plot using higher counts ((5±1.5)·106.cfu·mL-1) for the third experiment. Composite plant samples were collected in each plot: 0, 1 and 2 days after irrigation during the first experiment, 0, 3.5, 11, 22, 46, 166 and 214 hours after irrigation (second one) and using the same frequency for sampling as described by the surface of the soil (third one). Salmonella count was determined using Brillant Green and Rapport Agar plates incubated at 43 ºC. Plant and soil samples (25g) were diluted in 225mL peptone buffered water with increasing dilution values. Thus, the results are presented in cfu·mL-1. Presence test were also made in all the samples for the second and third experiments. More detailed procedures, which were already described for second experiment, are presented in Palacios et al., 2001. RESULTS AND DISCUSSION Salmonella ausence was found in all the water, soil and plant samples before the experiments. Likewise, Salmonella ausence and non detectable counts were found in every soil and plant samples irrigated with non inoculated water (control) during the experiments. Results of Salmonella counts for the third experiment in plots irrigated with inoculated reclaimed water are shown in Fig. 1. Plant data from the first and the second experiment are also represented. 10000000 1000000 cfu/mL 100000 10000 1000 100 10 time 1 12:00 a.m. 6:00 a.m. 12:00 p.m. 6:00 p.m. 12:00 a.m. 6:00 a.m. 12:00 p.m. 6:00 p.m. 12:00 a.m. 6:00 a.m. 12:00 p.m. 6:00 p.m. plant (3rd exp) soil:surface (3rd exp) soil:0.15m (3rd exp) soil:0.45m (3rd exp) plant (1st exp) plant (2nd exp) 12:00 a.m. Fig. 1. Results of Salmonella counts obtained during the third experiment (November), in cfu·mL-1 (Artificially inoculated reclaimed water: (565±85)·103 cfu·mL-1 (second experiment) and (412±73)·103 cfu·mL-1 (third one) for soil and plant samples). As result of the solar radiation effect, less bacteria counts were progressively obtained on plant (continuous line with lozenges in Fig. 1) over time during the day. In fact, since the first day following irrigation, some no detectable counts were obtained due to the presence of many environmental bacteria growing in the laboratory plates that difficult the detection of Salmonella, although presence 201 test detected it. These results were also obtained by the second experiment and are coincident with obtained by other authors (Turpin et al, 1993). In order to represent these detectable but not countable results, it was decided to assign them the value three. During the night, Salmonella was able to grow although for 5 and 4 log(10) cfu·mL declines in the population organisms in plant samples from initially inoculated and from the first night population at field conditions respectively. These results were consistent for at least three days and for the three experiments demonstrating the solar radiation effect in bacterial death growing on the plant surfaces. Higher recovering was obtained during the spring nights of the 2nd experiment, probably due to the higher nocturnal temperatures (also affected by soil heat emission), from this season. Salmonella was detected for the 10 and 20 days before irrigation (3 and (9·103) cfu·mL-1, respectively). This result coincides with obtained by Ronconi et al., (2002) who demonstrated the persistence of E Coli in lettuces. Similarly, Guo et al., (2001) detected persistence of Salmonella in tomato plants and fruits over a longer period of time following inoculation at field conditions. Comparing plant and soil results we noticed that bacteria survival was higher on the soil surface than on the plant samples. Although as occurred in plant samples an initial declination in bacterial populations was obtained from the sunrise to the noon, bacteria mortality was low and it was able to recover high populations even during the day. It is probably due to the solar radiation attenuation caused by plant and soil particles shading. Results obtained in subsoil samples (at 0.15 and 0.45m triangles and stripes in fig 1) are coincident with obtained in plant samples. Soil was able to effectively filtrate Salmonella, decreasing its population in 2 log (10) cfu·mL for the second day, but preferential flux may let the bacteria to reach subsoil at 0.45 depths. As obtained for the second experiment Salmonella seemed to need one day after irrigation to reach this depth. But, once in subsoil, it was able to survive at least 3 weeks in subtropical climates. This result is consistent which obtained by other authors (Ibenyassine et al., 2006). Fig. 2 represents the results for the comparative study from the effect of Salmonella competence with soil bacteria to radiation. Filled lozenges and discontinuous line represent sterilized soil plates results with lozenges for the 2nd and 3rd experiments respectively, while ultra violet radiation blocked plates (filled with non sterilized soil) are represented by addition signs and continuous line with asterisks (2nd and 3rd experiments respectively). Radiation seems to be the main cause of Salmonella death in soil samples during the spring season (2nd experiment, with spring longer day duration) while natural soil bacteria competence could be the main factor affecting in autumn (3rd experiment), coinciding with Turpin et al. (1993). Hence, the season effect could explain contradictory results obtained by many authors. As latitude condition day duration too, the conclusions obtained with local survival studies have not to forget this factor. You et al. (2006) also founded higher Salmonella persistence when manure is applied to sterilized soil comparing to no sterilized one. 100000000 10000000 cfu/mL 1000000 100000 10000 1000 100 10 time 1 12:00 AM 6:00 AM 12:00 PM soil:surface (3rd exp) sterilized soil plates uv blocked plates (2nd exp) 6:00 PM 12:00 AM 6:00 AM 12:00 PM soil:0.15m (3rd exp) uv blocked plates 6:00 PM 12:00 AM 6:00 AM 12:00 PM 6:00 PM 12:00 AM soil:0.45m (3rd exp) sterilized soil plates 2nd exp) Fig. 2. Results of Salmonella counts obtained during the second (spring) and the third (autumn) experiments, in cfu·mL-1 (Artificially inoculated reclaimed water: (412±73)·103 cfu·mL-1 for soil samples and (565±85)·103) cfu·mL-1 for plates. 202 In the 3rd experiment, and when soil bacteria competence was eliminated, even an increase of 1 log (10) cfu·mL was measured during the first two days after irrigation. This result coincided with obtained by You et al. (2006) who founded a Salmonella concentrations increase by up to 400% in the first 1 to 3 days after inoculation following by a steady decline. Once again, the solar radiation attenuation caused by plant and soil particles shading, joined to competence elimination could explain this increment in Salmonella populations. Comparing the results obtained by surface soil and plates with subsurface soil (triangles and stripes, fig 2), and considering results obtained by Al-Nakshabandi et al. (1997) and Batarsseh, et al. (1989a,b) we concluded that soil bacteria “filtration” was the main factor to decrease pathogen risk associated with reclaimed water irrigation. Complex transport behavior other than advection-dispersion, simple retardation and first order removal has been observed in many biocolloid transport experiments in porous media (Cortis, et al., 2006). Colloid transport in subsurface environments is critical to solving problems related to groundwater pollution by microbial pathogens (Saiers and Ryan, 2006). In this sense, subsurface drip irrigation systems (SDI) must be considered as the safer way to reuse reclaimed water. Contradictory results were obtained by Assadian et al., (2005) who concluded that preferential flow of irrigation water to the surface of clayey soil columns promoted virus movement to the soil surface when using SDI. In spite of this, many authors mentioned that associated with increasing irrigation frequency (comparing drip and furrow irrigation) less vertical cracking clay was observed (Hodgson et al., 2005). This second experiment was carried out at field conditions, while Assadian et al. worked in soil columns. CONCLUSION High Salmonella levels artificially inoculated, higher than may be expected in any reclaimed water used for irrigation, were used in these studies. Analysing the results obtained by this 3rd experiment we are now able to demonstrate our previous hypothesis: Salmonella was able to survive at least 3 weeks on plant, surface and subsurface soil samples at field conditions in subtropical climates. Soil was able to effectively filtrate Salmonella, but preferential flux may let the bacteria reach subsoil at 0.45m depth. Due to this fact, soil physical properties, irrigation system and water management will have an effect on the sanitary risk associated to reclaimed water irrigation. In this sense, SDI must be considered as the safest irrigation method. The solar radiation declined pathogen’s populations from initially inoculated on plant and soil surface during the day. In spite of this, during the night Salmonella was able to re-grow, basically depending on the nocturnal temperatures, also affected by the soil heat emission. Radiation was the main cause of Salmonella death in soil samples in spring while natural soil bacteria competence was the main factor affecting in autumn, when the solar radiation attenuation caused by plant and soil particles shading seemed to be a critical factor. REFERENCES Al-Nakshabandi, G.A., Saqqar, M.M., Shatanawi, M.R., Fayyad, M., Al-Horani, H. (1997).Some environmental problems associated with de use of treated wastewater for irrigation in Jordan. 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