Sustainability
and
Role of Bio-fertilizers
Dr. Bhavesh Patel
Principal
V.P. and R.P.T.P. Science College, Vallabh Vidyanagar
Email- [email protected]
The Presentation Focuses On
 Fertilizer Consumption and Food Grains
Production Scenario in India;
 Causes of Declining Crop Productivity;
 Sustainability of Farmers;
 Deficiency of Nutrients in Soil;
 Use Of Balanced Fertilizers and Biofertilizers;
 Comparison to other Countries.
Stagnation in Food grains Production in India
• Till 1997-98 strong
correlation is found
between Fertilizer
consumption and food
grains production
Exploring Relationship Between Foodgrain
Production & Fertilizer Consumption
18000.0
180
NPK Consumption
140
12000.0
120
10000.0
100
8000.0
80
6000.0
60
4000.0
40
2000.0
20
0.0
0
in Million MT
in '000 MT
160
Foodgrain Production
14000.0
2002-03
1999-2000
1996-97
1993-94
1990-91
1987-88
1984-85
1981-82
1978-79
1975-76
1972-73
1969-70
1966-67
Some states witness
consumption of fertilizer
picking up without any
conspicuous gain on
agricultural crop
productivity
200
16000.0
• After 1997-98, this
relationship distorted
Most of States are
experiencing increase in
fertilizer consumption
with slower pace of crop
productivity
20000.0
The Role of Fertilisers
• Increase productivity
• Therefore, there has to be a positive correlation
between use of fertilisers and crop yield
• The crop yield is falling and not in proportionate
to fertilizer consumption
COMPARISON TO OTHER COUNTRIES
Country
Fertiliser Uses
Kg/Ha
1
India
104.7
2
Pakistan
164.1
3
Bangladesh
188.6
4
France
215.9
5
Sri Lanka
271.8
6
China
275.1
7
United
Kingdom
315.1
8
Egypt
471.5
9
N. Zealand
668.5
Country
2003
Kg/ha
2004
Kg/ha
Increase
in Yield
Kg/ha
Egypt
7209
7347
138
China
4745
5044
299
Srilanka
3219
3475
256
India
2098
2103
5
Due to higher level of
consumption, productivity is on
rise in Egypt, China, Srilanka
Causes Of Declining Crop Productivity
• Imbalanced and indiscriminate use of chemical
fertilisers
• Occurrence of multi-nutrients deficiency such as
Zinc, boron, sulphur etc. besides NPK
• Rain dependent agriculture - About 2/3 area
• Inadequate irrigation facilities
• Continuous fragmentation of land, unfavourable
for adoption of technology
• Land holding pattern and Predominance of
marginal and small farmers
Major Cause: Nutrient Deficiency In Soil
Photosynthesis: CO2 + H2O  carbohydrates (CHO) + O2
• Besides NPK, Sulphur, Zinc
And Calcium are also
required in good quantity.
• Other nutrients such as
Iron, Boron etc. though
required in small quantities,
but their deficiency
significantly impacts plant
growth & life.
Nutrients are taken up primarily by the roots
in the form of an aqueous solution in the soil
• Micronutrient deficiency
(Zn, Boron, Iron & Sulphur)
in Indian Soil is increasing
Innumerable experiments prove there is Significant increase in Yields by
application of secondary & micronutrients along with NPK nutrients
Use Of Balanced Fertilisers
• Use of Balanced Fertilizers, Organic fertilizers and
Bio-fertilizers can provide viable leverage to increase
crop productivity
• It enrich the soil with important nutrients
• Bio-fertilizers has potential to generate additional
income to farmers from the same size of land
• Types of Bio-fertilizers
–
–
–
–
Rhizobium, Azotobactor,
Azospirillium, PSB
BGA, Azolla
Mycorrhiza
Benefits from Biofertilizers
• Low cost, easy technique
• Free from pollution hazards
• Increase soil fertility
• Quantity required decreased year by year
• Cyanobacteria secrete growth promoting substances like
IAA, IBA, NAA, AA, Proteins, Vitamins etc.
• Many agents secretes antibiotics which act as pesticides
• It improves physico-chemical properties of soil
• Harmless to human and animals
Nitrogenous Biofertilizers
N2 + 3H2
2NH3
• Fritz Haber (German Chemist) developed a method for
production of ammonia
o
• The reaction is carried out at 800 F, high pressure and
require high energy up to 13500 Kcal/ Kg of Nitrogen fixed
• Nitrogenous biofertilizersAzolla > Rhizobium > Cyanobacteria >Azospirillum >
Azotobacter
Rhizobium
• Nobbe and Hiltner introduce the laboratory
culture of rhizobia with the name “Nitragin”
in 1895
• This organism can be isolated from soil or
root nodule (preferably) after sterilizing the
root nodule by mercuric chloride or
sodium hypochlorite solution or 90% ethanol
• YEMA, 3-4 days, 28-30oC
• Colonies are white, translucent,
elevated with entire margin
Rhizobium - Identification
• CRYEMA test – Congo red + YEMA, rhizobium produce white
colony while agrobacterium produce similar but pink colony
• Microscopic observation – rhizobium upon staining with carbol
fuschin demonstrate the presence of PHB
• Lactose test – rhizobium do not utilize lactose
• Glucose Peptone Agar (GPA) test – rhizobium fails to grow
while agrobacterium grow well on GPA
• Salt tolerance test – YEMA+2% NaCl, rhizobium can not grow
but agrobacterium grow
• Nodulation test in pot
Microbial inoculants – Steps involved
• Isolation, identification of native strain
• Screening of best isolates and developing mother culture or
starter culture in YEM broth (28-30oC, 4 days)
• Cultivation on large scale using industrial media at pH 6.5-7.0,
5% inoculum, 4-7 days
8
9
• Measuring cell count (10 -10 cells/ml)
• Mixing the culture with carrier (Farm Yard Manure, Charcoal,
Lignite, Peat etc.)
• Packing and Storage (4-15oC)
• Transportation and application
Azotobacter
• Beijerinck isolated and described Azotobacter chroococcum
and A. agilis
• It fixes 20 – 40 Kg N/ha/annum
• Also produce IAA, GA, AA, Vitamines
• Recommended for rice, wheat, cotton etc.
• A. beijerincki, A. insignis, A. paspali, A. macrocytogenes,
A.vinelandii are the other spp.
Azotobacter - Characterstics
• Gram negative, rod shaped, aerobic, peritrichously flagellated
• Grow well at 25-30oC, high humidity, aeration, pH 7.2-7.6, high
salt conc.
• Forms cyst which resist unfavorable conditions (UV,
desiccation)
• Isolation can be done from soli using N free media like Ashby's
manitol media, Jensen's media
• Colonies are flat, soft, milky and mucoid
• Steps involved in large scale productions and application are
same as rhizobium
Azospirillum
• In 1925, Beijerinck isolated nitrogen fixing bacteria from root of
grass in Brazil and named it as Spirillum lipoferum
• In 1978, Tarrand renamed spirillum as Azospirillum
• It is an associative symbionts, colonise on root and sometime
infects cortex, without developing any apparent structure on
roots
• Fixes 20-40 Kg of N/ha/annum under microaerophilic conditions
• A. lipoferum, A. brasilense, A. amezonens, A.
halopraeferns, A. irakense are the known spp.
Azospirillum
• Isolation can be done from soil or root surface after sterilization
with 0.1% mercuric chloride
o
• Media used for growth contains sodium malate (28-30 C,2
days). Medium turns blue in presence of Azospirillum
• Azospirillum is a Gram negative, motile, containing PHB
• Aerobic to microaerophilic in nature
• Suitable carbon sources are malate, succinate, lactate,
pyruvate, poor growth on glucose or citrate
• For mass cultivation ammonium chloride containing Okon's
medium is recommended
Phosphate Solubilising Bacteria(PSB)
• P is second vital nutrient after N for the growth of plants
• P available in soil is in insoluble form
• Generally supplied in the form of superphosphate
• Many organisms in the soil solublises phosphate
eg. Pseudomonas, Bacillus, Micrococcus, Flavobacterium,
Aspergillus, Penicillium, Fusarium, Sclerotium etc.
• PSB produces organic acids like lactic, succinic, propionic,
formic acid etc. Consequently bound form of phosphate
solubilises and charged molecule of phosphorus are absorbed
by plants. Pikovskaya medium is used for isolation.
Cyanobacterial Inoculants
• Role of blue green algae (Anabaena, Nostoc, Plectonema,
Aulosira, Cylindrospermum) in the paddy field is well known
• In water lodging condition cyanobacteria multiply, fix nitrogen
and release it in the form of amino acids, proteins and other
growth promoting substances
• Cyanobacteria can be isolated on fogg’s medium by adding soil
from paddy field
• After proper agitation, flask is incubated at RT under the
influence of 12 hrs of light and dark regime
• Further isolation and purification is made using solid medium
Cyanobacterial Inoculants-Mass cultivation
• For mass cultivation pure culture of BGA is used as inocula
• Methods for mass cultivation involves –
- cemented tank method
- shallow metal troughs method
- polythene lined pit method
- field method
• BGA after growth can be dried, powdered, kept in sealed
polythene begs and supplied to the farmers
• Cyanobacterial inoculants can be stored for more then 3 yrs
with out any loss in viability (10 kg BGA/ ha of paddy field)
Azolla
• Azolla is an aquatic heteroporus fern which contains an
endophytic cyanobacterium, Anabaena azollae in its leaf cavity
• A total of six spp. of Azolla are known i.e. A. caroliniana, A.
filiculoides, A. mexicana, A. microphylla, A. nilotica, A. pinnata,
A. rubra
Azolla
• For good growth of Azolla P2O5 is added in water pond, pH is
maintained 8.0 and temperature between 14-30oC. An
insecticide furadon is added to check the growth of insects.
After 3 weeks Azolla is harvested, dried and applied
• Azolla shows tolerance to heavy metals like Hg, Pb, Cu, Cd, Cr
Thank You