Improving Food Security for Smallholder Farmers in Western Kenya: The Effects of Biochar on Long-term Maize Yield Dynamics

David Guerena & Johannes Lehmann

Source: FAO

Production Constraints

Soil fertility main biophysical constraint

Limited access to fertilizers High Costs High soil degradation

Low soil organic matter Inefficient fertilizer use

Historic rain sufficiency 2009 poor rainfall

Chronosequence: Soil health restoration

Established 2004

Soil degradation sequence

10 to 100+ year old farms

27 farmers 1-2 ha

Treatments

Applied organic amendments to maize LR 2004/2005, SR 2004

6 t/ha C Sawdust Tithonia diversifolia Manure Biochar (charcoal)

Fertilized and non-fertilized

Previous results and conclusions Increased yield over

control Biochar and Tithonia

Not due to greater nutrient status

Water availability?

Beneficial soil microorganisms? Mycorrhiza

July and August 2009

Objectives Measure longer term yield response Determine plant water status during critical

periods (grain filling) Measure soil physical characteristics

Infiltration and water holding capacity Collect yield data for farmers own practices

Grain Yield With Fertilizer LR 2009

Grain Yield Across Treatments

0

1

2

3

4

5

6

Fert No Fert Fert No fert Fert No Fert Fert No Fert FarmerPractices

Biochar Sawdust Tithonia Control

Yie

ld (t

/ha)

Water Stress

ABA ABA water stress

hormone Acute Stress Sampled in grain fill

Proline Chronic water

deficiencies Measured at harvest

Relate to yield In Process

Some Extension Work

Questions?