Conservation Agriculture for
smallholder farmers in Ethiopia
Melesse Temesgen (PhD)
Agricultural Engineer
Principal Researcher, Aybar Engineering PLC
Mobile: 0911245701
Email: [email protected]
The problem
• Conventional tillage causes soil degradation
and timeliness problems
• Land degradation:
– loss of soil organic carbon and soil erosion
caused by:
– Soil inversion and plowing at high speed.
– Plowing at uniform depth leads to soil
erosion and hardpan formation
– plowing up and down the slope accelerates
loss of soil and water
The problem (cont’d)
• Timeliness:
– Plowing and harrowing
– Repeated cross plowing with Maresha
• V-shaped furrows –unplowed strips of land
• Too much time spent on already plowed soil
• Clods formed through failing soil by pushing with
blunt wooden wings necessitates repeated plowing
and requires high draft power to prepare fine
seedbed
Conservation agriculture
• Principles (action based)
– Minimum soil disturbance
– Permanent soil cover
– Crop rotation
• Definition based on practice not objectives.
• Conservation agriculture aims at minimizing:
– loss of soil organic carbon
– Loss of soil moisture
– Soil erosion
– Pests and diseases
– Energy and time requirement
Global distribution of CA
Soil moisture, soil temperature & power source
Source: Derpsch,R., Friedrich,T.,
Kassam, A., Hongwen, L. 2010. Current status of adoption
of no-till farming in the world and some of its main benefits. Int J Agric & Biol Eng. Vol. 3 No.1.
Open Access at http://www.ijabe.org
Challenges to CA adoption by
smallholder farmers
• Mixed crop-livestock farming – competition for
crop residues
• Shortage of rainfall to maintain soil cover
• Lack of appropriate implements
• Chemical weed control more costly than
manual/animal powered mechanical weed
control (less costly than tractors)
• Adulteration of herbicides
• Health and environmental hazards of Herbicides
(New findings on grain toxicity from Glyphosate)
Is Roundup safe?
• According to Dr Joseph Mercola, in 2009, a French court
found Monsanto guilty of lying; falsely advertising its
Roundup herbicide as "biodegradable," "environmentally
friendly" and claiming it "left the soil clean (Mercola,
2013). In the article it is also stated “You'd also be wise
to stop using Roundup around your home, where
children and pets can come into contact with it simply by
walking across the area.”
Mercola, J. 2013. Monsanto’s Roundup Herbicide May Be
Most Important Factor in Development of Autism and
Other Chronic Disease. Available online:
http://articles.mercola.com/sites/articles/archive/2013/06/
09/monsanto-roundup-herbicide.aspx
CA for smallholder farmers
• Identify root causes of soil degradation
• Other African countries: Use of moldboard plows
that invert, pulverize and smear the soil
• Ethiopia: Use of Maresha, which creates V
shaped furrows with unplowed strips of land and
which produces too many clods, forces farmers
to carry out repeated cross plowing.
• Result: Loss of soil organic carbon, formation of
plow pans, loss of water through surface runoff
and evaporation, soil erosion and low biomass
production
Problems with Maresha plowing
• Creates V-shaped furrows with
unplowed strips of land
• Too much time spent by plowing
already plowed land in search of
missed strips
Problems with Maresha plowing
•Plowing up and down the slope
•Increased flow momentum (high
surface runoff and soil erosion)
•Too low and too high rake angles of
plow while plowing up and down,
respectively.
•Strenuous and energy demanding
Problems with Maresha plowing
(cont’d)
Difficult to plow fields with soil conservation
structures due to short turning distance
Poor distribution of water within a terrace leads to either
waterlogging at lower part or dry soils at the upper part in
addition to risking bund failure and accelerated erosion
Problems with Maresha plowing
(cont’d)
• Opens up the soil leading to
higher evaporation and loss of soil
organic carbon.
• High draft power requirement due
to cutting with blunt wooden wings
• Long travel distance of soil along
wooden wings increases draft
forces.
• Failing soil by pushing results in
clod formation due to failure along
slip lines. More plowing is needed
to reduce clod size.
Why urge farmers to reduce
plowing while using Maresha?
• No farmer would like to waste time and
energy on repeated plowing.
• The solution: we have to provide them with
an efficient tool that minimizes tillage
• We have identified the root causes of
repeated plowing with Maresha
• The next step is to come up with
something that removes those root causes
Silet Deger
.
Attached to the traditional plow,
Maresha, replaces the Deger
• Makes use of soil mechanics principles
• Designed to cut soil deep at the center &
shallow on the sides over a span of 36cm
• Integrates ripping with weeding
Advantages of Silet Deger
• Cup shaped furrow
– Disrupt plow pan at the center for increased
infiltration and root growth
– Shallow cutting on the sides to kill weeds
– Possibility of CA without Glyphosate
•
Reduced costs, reliability, reduced risk on health
and the environment.
– Formation of invisible barriers that mimic the
actions of soil conservation structures
Advantages of Silet Deger
(Cont’d)
• Wings designed for efficient soil cutting
– Reduced draft power requirement
– Reduced clod formation
• Reduced soil inversion
– Moisture conservation through reduction of
soil evaporation (soil mulching)
– Reduced loss of soil organic carbon
– Reduced draft power requirement
• Reduced deforestation
Advantages of Silet Deger (Cont’d)
• Avoids cross plowing
– Reduced energy and time requirement
– Reduced surface runoff (improved soil
moisture availability)
– Reduced soil erosion
– Convenient plowing between soil
conservation structures
– Reduced tillage frequency
– Improved timeliness of operation and/or
increased cultivable land
– Reduced cattle population
Test results
• Soil cutting performance (Sululta, Oromia, 2015)
Parameter
Mean furrow depth (cm)
Average minimum depth (cm)
Invisible barrier height (cm)
Max depth (cm)
Implement
Maresha Arashogel
11
16
0
9
7
14
19
Soil profile before and after plowing
0
50
100
150
200
250
300
350
0
5
10
•
.
Before plowing
After plowing
Maresha
15
20
25
30
35
40
0
50
100
150
200
250
300
0
5
10
15
Silet Deger
Before plowing
After plowing
20
25
30
35
40
Silet Deger penetrated deeper with complete plowing
in one pass while leaving invisible barriers to retard
runoff and reduce soil erosion
Effects on surface runoff and
soil loss
Effect of tillage method on surface runoff and soil loss (Bolo Sellase, Minjar,
Amhara RS, 2013). Laike Kebede et al.Unpublished data
Surface runoff coefficient (%)
soil loss
slope (%)
TT
CT
% reduction
TT
CT
% reduction
3
8.1
3.00
63.0
0.87
64.7
2.46
8
22.4
9.70
56.7
12.52
3.30
73.7
14
29.6
15.30
48.3
3.72
73.9
14.26
TT=Maresha, CT= Arashogel
Effect of CT with Silet Deger on
crop yields
• Nine farmers participated in an on-farm trial in
Semen Achefer, Bahrdar Zuria and Gonder zuria
districts of Amhara region
• Crop yields increased in all sites with a
maximum increment of 100% in wheat yield
(Mastewal Melkamu, Agronomist, BoA of Semen
Achefer) and Tef and Sorghum (Melke Belay,
Agronomist, BoA of Gondor Zuria woreda)
Waterlogging in vertisols
• Vertisols are fine textured soils with poor
drainage resulting in seasonal waterlogging
(water stagnation on the surface)
• 7.6 million hectares of vertisols in Ethiopia suffer
from waterlogging problems
• Farmers can effectively cultivate only 1.9Mill ha
• Plowing until September to plant chickpea leads
to soil erosion and emission of CO2
• Seasonal waterlogging leads to production and
emission of NH4 (20 times more potent than CO2
as GHG)
Construction of BBF to drain
excess water in vertisols
• Broad bed and furrows (BBF) constructed
at planting can drain excess water
• Development of appropriate BBF maker
(BBM) started in 1984.
• Farmers rejected earlier
models because of high
draft force, heaviness, poor
performance, etc
• Aybar BBM addressed all
complaints of farmers
• Crop yields increased by
upto 300%
Reversing the role of water from emission
of GHG to carbon sequestration
• Drainage allows early planting, which replaces
CO2 emission from plowing by carbon
sequestration from live crops in addition to
reducing soil erosion and generating additional
income to farmers
• Drainage reduces production and emission of
NH4
• Drained excess water stored in ponds is used to
irrigate a 3rd crop thereby extending soil cover by
live crops
.
Thank you