An overview of soil fertility management, maintenance, and productivity in Kenya

Abstract

Soil fertility-related issues are a major concern to Kenya. For more than a decade, the country has experienced a declining trend in agricultural production as exemplified by low yields of major crops. Crop yields of no inputs declined by over 70% in 11 years. Continuous cropping without fertilizer caused declines in soil organic carbon and microbial biomass size and activity compared to farmyard manure alone or in combination with inorganic fertilizer. In fertilizer trials throughout the country, nitrogen (N) and phosphorus (P) were deficient in 57% and 26% of the sites, respectively. With declining productivity and soil nutrient depletion, many farmers have taken the initiative to improve the situation by use of both inorganic and organic nutrient sources such as manures, composts and traditional fallows where possible. There is strong evidence that application of fertilizer increases crop production, especially for maize. Among the bio-physical factors, a soil fertility decline remains the single most important constraint to food security in this region. After soil moisture stress, low soil fertility is the most important constraint limiting crop productivity in sub-Saharan Africa.