David Presentation Jan 7 2009
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Transcript of David Presentation Jan 7 2009
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?