Conceptual typology of Conservation Agriculture systems for Semi Arid and Sub-Humid areas in West and Central Africa

1. Conceptual typology of
Conservation Agriculture systems
for semi-arid and sub-humid areas
in West and Central Africa
Dr Patrice Djamen
18th-21th March 2014, Lusaka, Zambia
1st African Congress on Conservation Agriculture:
CA: Building entrepreneurship and resilient farming systems

2. Articulation
• Context and objective
• Methodology
• Results
• General discussions and conclusion

3. Poor soils
ContextHow to achieve
the sustainable
intensification
of farming in
WCA?
© P. Djamen
Poverty
Source: Tittonell & Giller, 2012
Low productivity
0
100
200
300
400
500
600
700
800
900
1000
2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013
Rainfall(mm/year)
Year
Annual Rainfall in Yilou (BF)
Poor and erratic
rainfall
Food insecurity
Etc.

4. What should be the local color(s) of CA in WCA?
Durable
Vivable
Viable
ENVIRONNEMENT
ÉCONOMIE
Équitable
SOCIAL
?
• Four agroecosystems (Jalloh et
al., 2012) : semi arid, sub-humid,
humid forest, and swamp
• Population density : from < 20 to
> 80 ihbts/km²
• Etc
If yes, how to implement it
considering the wide diversity
of socioeconomic and
agroecological conditions ?
Is CA an Option?
Objective: To develop potential CA options matching the
variability of local conditions in WCA

5. PADER-BGN : Programme d’Appui au
Développement Rural en Basse Guinée Nord
PICOFA : Programme d’Investissement
Communautaire en Fertilité Agricole
PDRD: Programme de
Développement Rural Durable
PPILDA: Projet de Promotion de l’Initiative
Local de Développement à Aguie
300 – 450
mm/year
800 – 1,000
mm/year
600 – 700
mm/year
2,000 – 3,000
mm/year
Methodology
Research conducted in the framework of SCAP >> Burkina Faso, Guinea, Niger
Potential and implementation modalities of CA in WCA ?

6. Methodology
• Review of existing knowledge on past and on-going CA
operations developed in WCA
• Diagnosis of farming practices, biophysical and socio-
economic characteristics of the study site
• Participatory identification of options for CA principles
Options Min soil Dist
(MSD)
Permanent Soil cover
(PSC)
Crop diversification
(CDV)
MSD1 PSC1 CDV1
MSD2 PSC2 CDV2
MSD3 PSC3 CDV3
CA system (CA-S) = a particular combination of implementation modalities of
each of the three CA principles, the modalities being chosen according to their
suitability with the biophysical and socioeconomic characteristics of the
environment and farms where they are applied.
CA-S = MSDk + PSCd + CDVp
K, d, p = options respectively for minimum soil disturbance,
permanent soil cover and crop diversification

7. CA principles
• 1. Minimum Soil Disturbance:
– no-tillage and direct seeding;
– The disturbed area must be less than 15 cm wide or less than 25% of the
cropped area
– no periodic tillage that disturbs a greater area than the aforementioned
limits.
– Strip tillage is allowed if the disturbed area is less than the set limits.
• 2. Organic soil cover:
– three categories are distinguished: 30-60%, >60-90% and >90% ground cover
at the seeding operation.
– Area with less than 30% cover is not considered as CA.
• 3. Crop rotation/association: at least 3 different crops.
http://www.fao.org/ag/ca/6c.html

8. Results
Soil cover
i. Density
– 30 – 60%
– 60 – 90%
– > 90%
ii. Type of
materials
– Crop residues
– Grasses
– Biomass from
trees/shrubs
Crop diversification
i. Diversification
pattern:
– Crop association
– Crop rotation
ii. Main functions of
crop
– Food security /
income
– Animal feeding
– Soil fertility
Min soil disturb.
i. Pattern
– Zero tillage
– Ripping
– zaï
ii. Use of
herbicides
– Yes
– No
implementation modalities of CA principles identified

9. Results
• 1. CA-S 1: CA featuring agroforestry, direct seeding under mulch
from tree/shrub pruning, cereal in association with leguminous
food crops
• 2. CA-S 2: CA featuring crop residue retention; direct seeding under
mulch of crop straws, cereal in association preferably with
leguminous food crops
• 3. CA-S 3: CA featuring cover crops, direct seeding under biomass
of cover crops, cereal in association or rotation with fodder crops.
• 4. CA-S 4: CA featuring cover crops, direct seeding under mulch of
cover crops, cereal in rotation with fodder crops or improved fallow
Four CA-Systems adapted to local conditions

10. CA-CS 1
Soil tillage Direct seeding /ripping
Material for
organic soil cover
Biomass of shrubs
(Piliostigma reticulatum,
Guiera senegalensis,
Hyphaene thebaïca)
Main crop Millet / sorghum
cover crops /
associated crops
Cowpea / peanuts
Crop association /
rotation?
Association
Average accessible
soil cover rate
30 – 60%
i/ CA featuring agroforestry,
Four CA-Systems adapted to local conditions

11. Four locally adapted CA systems
CA -S 2
Soil tillage Direct seeding / ripping
Material for
organic soil cover
Mulch of cereal
eventually complemented
with biomass of shrubs
or grass
Main crop Sorghum / millet
cover crops /
associated crops
Cowpea / peanuts
Crop association /
rotation?
Association
Average accessible
soil cover rate
50 – 70%
iI/ CA featuring crop residue retention, DS, Cereal in association
with leguminous food crops

12. CA - S3 CA- S4
Soil tillage
Direct seeding +
herbicide
Direct seeding +
herbicide
Material for organic
soil cover
biomass of cover crops +
straws of cereal
Biomass or cover
crops + grasses
Main crop Maize, sorghum, cotton Rice / maize
Cover crops /
associated crops
Fodder crops (brachiaria,
mucuna, dolichos etc.)/
leguminous food crops
Fodder crops
(brachiaria, pigeon
pea, dolichos,
mucuna etc.)
Crop association /
rotation?
Association / Rotation Rotation
Average accessible
soil cover rate
80 – 100 100%
Four locally adapted CA systems
CA featuring cover crops : CA-S3 & CA – S4

13. Populationdensity
(inhabitants/km²)
600 1,000 1,400 Rainfall (mm/year)
20
40
60
CA- S 1: CA
feat.
agroforestry,
cereal +
legum. food
crops CA-S2: CA feat.
residue
retention,
cereal mixed
with
leguminous
grain
CA-S 4: CA featuring cover
crops, cereal in rotation
with fodder crops
/improved fallow
CA-S 3: CA featuring cover
crop; cereal intercropped
/ in rotation with legumes
food crops / fodder crops
Source: Djamen et al. 2013. Conservation Agriculture in West and Central Africa
The four CA-
systems are
not exclusive

14. Discussions and conclusion
• Further knowledge still needed on the performance
and operational modalities of CA-S in WCA
CA-CS1 CA-CS2 CA-CS3 CA-CS4
Biophysical ++ +++ +++ ++++
Socio-economics effects + ++ +++ ++
Implementation
modalities
+ +++ +++ +++
Impacts

15. Discussions and conclusion
• The proposed typology can be refined through a better
integration of livestock, irrigated agriculture and mechanization
• Are the expected benefits of CA the same in all contexts?
CA-CS1 CA-CS2 CA-CS3 CA-CS4
Soil fertility ++ + + ++++ ++++
Food security and
revenue
++++ +++ ++ ++
Animal feeding ++ ++ ++++ ++++
Labour
requirements
- - - - - +++ +++
Caption: + = positive effect; - = negative effect; the number of signs shows the importance of the effects

16. Merci pour votre
attention