Mucuna pruriens differentially affect maize yields in three soils of Kakamega District

Abstract

Maize production in smallholder farming systems in Kenya is largely limited by low soil fertility. As mineral fertilizer is expensive, green manuring using leguminous cover crops could be an alternative strategy for farmers to enhance farm productivity. However, due to variability in soil type, the effects of green manure are likely to differ with farms. This study was conducted in three contrasting soils in Kakamega District, Kenya, to evaluate Mucuna pruriens on (i) biomass and nitrogen fixation (¹⁵N natural abundance) and (ii) the effects on maize yields over two cropping seasons. Mucuna at 6 weeks accumulated 1-1.3 Mg ha^-1 of dry matter and 33-56 kg ha^-1 nitrogen of which approximately 70% was nitrogen derived from the atmosphere (Ndfa). Maize yield increased by 0.5-2 Mg ha^-1, 0.7-2 Mg ha^-1 and 1.5-4 Mg ha^-1 with Mucuna, farmyard manure and mineral fertilizer use, respectively, and the response was stronger in Nitisol than in Acrisol or Ferralsol. We concluded that green manuring using Mucuna seem promising in enhancing soil fertility and maize yields in Kakamega, provided soil conditions and rainfall are suitable.

Keywords: Acrisol, Ferralsol, green manure, Nitisol, nitrogen fixation