Benefits of the mbili-mbili maize-legume intercropping systems under subsurface water harvesting technology (SWRT) on sandy soils in the semi-arid Marange region of Zimbabwe

In semi-arid regions of southern Africa, smallholder farmers grow maize ( Zea mays L.) under rain-fed systems, even though their yields remain extremely low due to poor soil fertility and frequent droughts. Integrating water harvesting and legumes into these cropping systems can improve yields. This 3-year replicated field experiment investigated the benefits of mbili-mbili maize - legume strip cropping, where t wo rows of maize are alternated with two species of legumes , on crop yield in plots with or without subsurface water harvesting technology (SWRT) in Marange Zimbabwe. The treatments comprised of sole maize (SM), MBILI systems comprising maize + cowpea ( vigna unguiculata ) (M+CP) and maize + beans ( Phaseolus vulgaris ) (M+beans); and mbili-mbili systems comprising: maize + cowpea + bambara nuts (M+CP+BN); maize + cowpea + groundnuts (M+CP+GN); and maize + cowpea + beans (M+CP+beans). There were no significant differences between average maize grain yields in SWRT and no SWRT, and in sole maize (4.1 t/ha) and the strip-cropped systems (3.2-3.9 t/ha). However, during the low rainfall season (2021/22), sole maize had significantly higher grain yields than intercropped maize. MEY were; 1280, 1230, 1358, 1625, 1206 and 1330 kg ha ^-1 for Sole maize, M+CP, M+CP+BN, M+CP+GN, M+N45 and M+N45+CP, respectively. Although mbili-mbili intercropping had similar MEY to sole maize, it offered dietary diversity and high quality biomass (haulms). The MBILI and mbili-mbili intercrops also had higher returns on investment than sole maize, incomes ranged between $323-1487. We concluded that MBILI and mbili-mbili intercropping increased crop yields, crop and dietary diversity, and incomes with no penalties on the maize crop.