Farmers in Western Kenya traditionally row-crop maize with nitrogen-fixing legumes to increase yields and soil fertility. Nitrogen is returned to the soil from the falling leaves and decomposing roots of the bean plants. Researchers at the Sustainable Agriculture Centre for Research, Extension and Development in Africa (SACRED-Africa), noticed that the single rows were not providing enough light for the legumes, and that the second maize crop often failed due to insufficient late rains. To address these constraints, they pioneered a new system known as MBILI (Managing Beneficial Interactions in Legume Intercrops), meaning “two” in Swahili. MBILI consists of intercropping double rows of maize and legumes, allowing for better light and soil conditions, whilst maintaining the same plant populations. The system yields nearly 3 tonnes of maize and more than 500kg of legumes per hectare.
MBILI has been shown to increase production by 26% – 37% in the short rain season and around 7% in the long rain season. The greatest improvement is noted in groundnut which can increase by 101% compared to conventional conditions. Farmers earn an average of 31,689 KSh (US$325) per hectare using MBILI intercropping, compared to 26,333 KSh (US$270) with conventional methods.