Farmers' evaluation of legume cover crops for erosion control in Gathwariga catchment, Kenya

Abstract

Studies were conducted in Gathwariga catchment, Kenya with the aim of evaluating farmers' perception about the impact of legume cover crops (LCC) on soil erosion control. A sensitization workshop involving the farmers was held to discuss the benefits of using LCC for erosion control after which the farmers opted for the following treatments: pure stand of maize (Zea mays) (T1), maize intercropped with Mucuna pruriens (T2), maize plus Vicia benghalensis (T3) and maize plus Lablab purpureus (T4). All the farmers indicated that plots previously planted with LCC provided post-harvest cover to the soil almost 7 months after planting which was crucial in controlling erosion during the on-set of subsequent rains when the ground is bare. The post-harvest percent cover taken at the beginning of the subsequent season was 0, 43.2, 9.0, and 11.4% for T1, T2, T3 and T4 respectively. T1 had 9, 2 and 2.5 times more soil loss than T2, T3 and T4 respectively. The eroded sediments had higher concentrations of plant nutrient elements than the 'field soil'. A follow up visit showed that 84% of the farmers planted mucuna as a sole crop to control erosion in degraded areas, one used mucuna as an intercrop with cassava, two decided to plant mucuna on relatively flat areas for seed multiplication while one farmer had grown mucuna to reclaim a gully.