Socio-ecological niches for minimum tillage and crop residue retention in continuous maize cropping systems in smallholder farms of central Kenya

The prevalence of soil degradation and production constraints for smallholder farmers in Central Kenya offers an opportunity for the application of conservation agriculture practices. However, much variability exists between smallholders, rendering the benefits of CA quite site specific. The purpose of this study was to determine the effects of minimum tillage and mulches on maize yields of twenty-one farms with varying soil fertility, size, and, cropping seasons. Two tillage and two crop residue trials were compared across three soil fertility classes from 2007 to 2009. It was determined that minimum tillage practices are inappropriate for good and poor soil fertility and most beneficial for farms of medium soil fertility. In order to raise agricultural productivity in Sub-Saharan Africa, additional studies that account for heterogeneity among smallholders is critical.