Soil heterogeneity and soil fertility gradients in smallholder farms of the East African highlands

Abstract

Heterogeneity in soil fertility in smallholder systems is caused by both inherent soil-landscape and human-induced variability across farms differing in resources and practices. Interventions to address the problem of poor soil fertility in Africa must be designed to target such diversity and spatial heterogeneity. Using a mixed model approach, data was collected from six districts in Kenya and Uganda that revealed a high variation in soil organic C, total N and available P was mostly related to differences in the inherent properties of soils across sites with field-to-field differences within farms. Soil fertility indicators decreased significantly with increasing distance from homesteads. Framers allocated nutrient resources to fields with high fertility. Categorizing of fields within a farm and soil fertility classes are good entry points to target soil fertility recommendations