Assessment of farmers' perceptions of soil quality indicators within smallholder farms in the central highlands of Kenya

Abstract

A study was conducted to determine farmers' perceptions of soil quality and soil management practices that influenced soil fertility within farmers' fields in Chuka and Gachoka divisions in central Kenya highlands. Soils were characterized by farmers after which they were geo-referenced and sampled at surface depth (0-20 ern) for subsequent physical and chemical analyses, to determine differences within farmers' soil quality categories. Special attention was given to agricultural weed species. Indicators for distinguishing productive and non-productive fields included crop yield, crop performance, soil colour and soil texture. A total of 18 weed species were used to distinguish between high and low soil categories. Significant differences among soil fertility categories implied that there were qualitative difference in the soils that were chacterised as different by farmers. Fertile soils had significantly higher pH, total organic carbon and exchangeable cations, with available-N being significantly different in Gachoka. Factor analysis on 15 soil properties identified 4 factors that explained 65% of the total variance in soil quality. Soil fertility and crop management practices that were investigated indicated that farmers understood and consequently utilized spatial heterogeneity and temporal variability in soil quality status within their farms as a resource to maintain or enhance agricultural productivity.