towards sustainable intensification of maize-legume cropping systems: kenya experience. john achieng

Towards Sustainable Intensification of Maize-Legume Cropping Systems:

Kenya Experience

SIMLESA PROJECT ACTIVITIES

Achieng, J., Micheni, A., F. Kanampiu

15th World Congress on Conservation Agriculture, Brisbane

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 potentialof ≥ 3.5 t


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


Objectives

Long-term:• To test resilient smallholder maize-legume 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-legume yield

• To test the capacity of APSIM to model performance of maize-legume systems under CA practices


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


Materials & Methods• 10 sites:

– low potential zone: 2 sites each in eastern and western Kenya

– medium potential zone: 2 sites each in eastern and western Kenya

– Two on-station: each in KARI Embu and Kakamega

• Participating farmers: 45 in Eastern, 130 in western; members of farmers’ groups

• Type of research: Participatory and farmer-managed


Materials & Methods Cont

Treatments (western Kenya)1. Conventional practice2. CA + non-inoculated beans3. CA + inoculated beans4. CA + desmodium

Treatments (Eastern Kenya)*1. Farmers’ tillage2. Conventional tillage3. Zero tillage4. Furrows & Ridges* Intercropped with either beans or pigeon pea


Materials & Methods Cont

Weather data

• Daily rainfall

• Daily Min & Max temp

• Daily Min & Max temp for 30 yrs

• Daily Radiation for 15 yrs

Rain gauge in a farmer’s home to record daily rain


Materials & Methods Cont.

• Soil DataSoil 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 10

Scientist and technicians examining degraded Western Kenya soils

Tumaini Farmers’ Field School members discussing pros and cons of CA


• Crop Data– Maize crop sampled 3 times each season

for chemical analysis– Maize & bean yield and related parameters


Materials & Methods Cont.Maize and beans grown under conventional practice, western Kenya

Maize and beans grown under CA practice, western Kenya


Materials & MethodsCrops under conventional practice in eastern Kenya Crops under CA in eastern Kenya


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Materials & Methods Cont.Residue retained in a maize crop in CA trial, western Kenya

Desmodium grown as a cover crop in maize in CA trial, western Kenya


Technology DisseminationThe District Commissioner being shown CA plots at Siaya Field Day

Provincial Administration staff attended the field day. DCs and Chiefs are influential and respected


Result : Water Use Efficiency

Treatment WUE (kg/mm/ha)

2010 LR Season

WUE (kg/mm/ha)

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


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Result: Siaya Crop Yield (2010 Season)

Treatment Beans (kg/ha)

Maize (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 yieldCA had no effect on maize yield

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Result : Siaya Crop Yield 2011 season

Treatment Beans (kg/ha)

Maize (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 practice5th World Congress on Conservation Agriculture, Brisbane

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Suitability of APSIM

The slope of the regression between observed and predicted yield is R2 = 0.9, indicating a high degree of accuracy


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0

1500

3000

4500

6000

0 1500 3000 4500 6000

Observed yield (kg/ha)

Pre

dict

ed y

ield

(kg

/ha)

Beans

Maize

1:1 line

R2=0.9

Maize grain yields under different tillage practices in on-farm trials in eastern Kenya

Beans grain yields under different tillage practices in on-farm trials in eastern Kenya

ConclusionsCombination 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 5th World Congress on Conservation Agriculture, Brisbane

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AchievementsoFarmers, extension and researchers

trained four timesoThree field-days heldoOne article in CIMMYT’s Informa

September issueoTwo articles in newslettersoOne documentary (CD) producedo3 papers presented at WCCA


Challenges

oCompetition for crop residues

oLack of appropriate implements to be used under very smallholder farms

oTermites that feed on residue



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towards sustainable intensification of maize-legume cropping systems: kenya experience. john achieng

Education

5th world congress

brisbane treatment beans

food security

methods cont

ca practices

ca trial

minimal tillage

tillage practices