Crop production in smallholder farming systems of Zimbabwe is limited by low inherent soil fertility, particularly N and P and available soil moisture. One of the major agricultural challenges in developing countries is the development of technologies that are able to sustain soil fertility and conserve soil and moisture. The use of legumes is one way this could be achieved and therefore there is need to select appropriate and beneficial legumes for smallholder crop production in Southern Africa. Hairy Vetch (Vicia villosa Roth) has great potential for improving the crop production of high N demanding crops such as maize (Zea mays). This study therefore seeks to investigate the effect of the cover crop, Hairy vetch (Vicia villosa Roth) on maize yield, determine its N contribution through biological nitrogen fixation (BNF), its biomass production, characterise its decomposition and nutrients N and P release patterns and its effect on soil and water conservation in smallholder farming systems of in central Zimbabwe. Two agro-ecological zones, Natural Region II (Rainfall 750-1000 mm/year) and in Natural Region III (Rainfall 450-650mm/year) were selected for this study. Preliminary results have shown that sunnhemp has the greatest biomass production followed by cowpea with hairy vetch having the lowest yield. Soil and foliar samples are being analysed and soil and nutrient loss being measured using rainfall simulation.