Soil Fertility Management Planning for Sustainable Maize-Yam Rotation Systems in the South East

This study develops soil fertility management plans for sustainable maize-yam rotation systems in South East Nigeria, addressing the specific nutrient dynamics, organic matter requirements, and fertility management challenges of this widely practiced rotation. Maize-yam rotation is one of the most economically important farming systems in South East Nigeria, generating both staple food and high-value cash crop income for smallholder farmers. Sustainable management of this rotation requires understanding the distinct nutrient demands and soil effects of each component crop. This study uses a combination of soil fertility monitoring on 20 farms with documented maize-yam rotation histories in Enugu, Imo, and Abia States with field experiments testing alternative fertility management strategies. Soil nutrient trajectories over rotation cycles, crop yield responses to different fertility management combinations, and economic returns are assessed. A soil fertility decision support tool is developed from the experimental data. Findings reveal that the yam phase is the most soil-depleting component, requiring 45 to 60 kilograms per hectare of potassium to maintain yield potential. The maize phase responds most strongly to nitrogen inputs. Integrated management combining organic matter addition before yam planting with mineral NPK for the maize phase maintains soil fertility while achieving economically optimal yields for both crops. The study concludes that rotation-specific fertility management plans significantly improve the sustainability of the maize-yam system. It recommends the decision support tool for use in extension and agribusiness advisory services in South East Nigeria.

Keywords: soil fertility management, maize-yam rotation, South East Nigeria, nutrient management, sustainable farming.