The Potential Role of Organic Soil Fertility Management in the Kenya Highlands

Summary

Soil fertility degradation still remains the single most important constraint to food production in the Kenyan Highlands. It is estimated that 64% of the population resides in the highlands, with population densities in some areas of over 1000 persons/km2. Use of inorganic fertilisers on smallholdings in the Kenya Highlands has been steadily declining since the 1960s, when heavy promotion and subsidization of fertilisers coincided with the release of improved maize varieties and the creation of co-operatives such as the Kenya Grain Growers Co-operative Union. Currently, their use continues to be constrained by their high cost, the low purchasing power of smallholders, and limited access to credit facilities. Farm sizes are getting smaller, and this promotes continuous cropping with limited scope for crop rotation and inadequate soil fertility replenishment. Soil fertility improvement can be achieved through organic farming techniques such as biomass transfer, re-activation of the ‘N bulge’, and phosphorus scavenging. Legume intercropping with maize – Kenya’s staple food – as well as the implementation of short rain legume fallows are known to enhance maize yields in most cases.