A presentation from the WCCA 2011 event held in Brisbane, Australia.

1. Sustainable intensification of maize-
bean production among smallholder
farmers in western Kenya
Achieng, J.1, F. Kanampiu2, Y. Chauhan3, D. Rodriquez4
1Kenya Agricultural Research Institute
2CIMMYT, Nairobi, Kenya
3Agri-Sciences Queensland, Toowoomba, Australia
4The University of Queensland, Toowoomba, Australia
5th World Congress on Conservation Agriculture, Brisbane 1

2. Introduction & Background
• Maize is a major staple food in Kenya
• Often grown in association with beans
• About 80% of maize produced by smallholders
• Current yield: ‹1.0 t ha-1 against potential
of ≥ 3.5 t
5th World Congress on Conservation Agriculture, Brisbane 2

3. Justification
• Conv. tillage practices have degraded the soils
• Droughts and long dry-spells are regular
• Use of inorganic fertilizers is not common
• Demand for maize increases by 4% annually;
Food security is threatened
• Need to embrace Conservation Agriculture to
restore lost soil fertility
5th World Congress on Conservation Agriculture, Brisbane 3

4. Objectives
Long-term:
• To test resilient smallholder maize-bean farming
technologies based on CA principles
Short-term:
• To investigate the effects of minimal tillage and
residue retention on water use efficiency, SOM and
maize-bean yield
• To test the capacity of APSIM to model performance
of maize-beans system under CA practices
5th World Congress on Conservation Agriculture, Brisbane 4

5. Expected Output
• About 30% increase in yield due to
adoption of CA practices within a period
of about 10 years
• About 30% decrease in production risks
due to adoption of CA practices within a
period of about 10 years
5th World Congress on Conservation Agriculture, Brisbane 5

6. Materials & Methods
• Sites: 5
– two in Siaya: low potential zone
– two in Bungoma: medium potential zone
– One on-station: medium potential zone
• Participating farmers: 130; members of
farmers’ groups
• Type of research: Participatory and
farmer-managed
5th World Congress on Conservation Agriculture, Brisbane 6

7. Materials & Methods Cont
Treatments
1. Conventional practice
2. CA + non-inoculated beans
3. CA + inoculated beans
4. CA + desmodium
Varieties: Depended on site and season
Fertilizer: CA treatments = 80 kg N and 60 kg P/ha
Conventional = 40 kg N and 30 kg P/ha
Plot Size: 20m X 17m
5th World Congress on Conservation Agriculture, Brisbane 7

8. Materials & Methods Cont
A farmer showing group
members how to record
Weather data weather data and rainfall trend
that month
• Daily rainfall
• Daily Min & Max temp
• Daily Min & Max temp for 30 yrs
• Daily Radiation for 15 yrs
5th World Congress on Conservation Agriculture, Brisbane 8

9. Materials & Methods Cont.
• Soil Data
Soil sampled from 4 layers (up to
90cm), 3 times a season for:
• Gravimetric water determination
• Bulk Density determination
• Chemical analysis
5th World Congress on Conservation Agriculture, Brisbane 9

10. Materials & Methods Cont.
Scientist and technicians examining Tumaini Farmers’ Field School members
degraded Western Kenya soils discussing pros and cons of CA
5th World Congress on Conservation Agriculture, Brisbane 10

11. Materials & Methods Cont.
• Crop Data
– Maize crop sampled 3 times each season
for chemical analysis
– Maize & bean yield and related parameters
5th World Congress on Conservation Agriculture, Brisbane
11

12. Materials & Methods Cont.
Maize and beans grown under Maize and beans grown under
conventional practice, western Kenya CA practice, western Kenya
5th World Congress on Conservation Agriculture, Brisbane 12

13. Materials & Methods Cont.
Residue retained in a maize Desmodium grown as a cover crop in
crop in CA trial, western Kenya maize in CA trial, western Kenya
5th World Congress on Conservation Agriculture, Brisbane 13

14. Technology Dissemination
The District Commissioner being Provincial Administration staff attended the
field day. DCs and Chiefs are influential and
shown CA plots at Siaya Field Day respected
5th World Congress on Conservation Agriculture, Brisbane 14

15. Result : Water Use Efficiency
Treatment WUE WUE
(kg/mm/ha) (kg/mm/ha)
2010 LR Season 2011 LR Season
Conventional 8.5 8.0
CA + non-inoculated beans 10.8 11.9
CA + inoculated beans 9.5 9.9
CA + desmodium 9.8 9.9
Conventional practice gave lower WUE compared to CA
CA practices progressively increased WUE while conventional
practice progressively reduced the WUE
15
5th World Congress on Conservation Agriculture, Brisbane

16. Result: Crop Yield (2010 Season)
Treatment Beans Maize (kg/ha)
(kg/ha)
Conventional 355c 4,075
CA + non-inoculated beans 626b 4,650
CA + inoculated beans 927a 4,416
CA + desmodium 707ab 4,483
Mean 654 4,406
LSD (5%) 231 ns
Rhizobial inoculation increased bean yield
CA had no effect on maize yield
16
5th World Congress on Conservation Agriculture, Brisbane

17. Result 2011 Season: Crop Yield
Treatment Beans Maize
(kg/ha) (kg/ha)
Conventional 640a 2,810b
CA + non-inoculated beans 520ab 5,150a
CA + inoculated beans 390ab 4,330a
CA + desmodium 320bc 4,310a
Mean 468 4,150
LSD (5%) 240 989
Conventional practice gave highest bean yield
CA practices gave higher maize yield compared to conventional practice
17
5th World Congress on Conservation Agriculture, Brisbane

18. Suitability of APSIM
Predicted yield (kg/ha) 6000 1:1 line
R2=0.9
4500
3000
Beans
1500 Maize
0
0 1500 3000 4500 6000
Observed yield (kg/ha)
The slope of the regression between observed and predicted
yield is R2 = 0.9, indicating a high degree of accuracy 18
5th World Congress on Conservation Agriculture, Brisbane

19. Conclusions
Combination of minimal tillage and residue
retention:
– maximized soil water use and hence can be an
effective tool in mitigating effects of drought
and prolonged dry spells
– More than doubled maize yield; food security
among smallholders can be achieved in a short-
run
APSIM can model performance of maize-beans
system under CA practices
Farmers beginning to appreciate CA
19
5th World Congress on Conservation Agriculture, Brisbane

20. Challenges
o Competition for crop residues
o Lack of appropriate implements to be
used under very smallholder farms
o Ants that feed on residue
5th World Congress on Conservation Agriculture, Brisbane 20

21. Acknowledgments
o KARI: For facilitating the research
o CIMMYT: For technical backstopping
o ACIAR: For financial support
o Western Kenya farmers: For
implementation
o WCCA Organizing Committee: For
accepting the paper
o This esteemed audience for accepting to
listen to the presentation
5th World Congress on Conservation Agriculture, Brisbane 21