The impact of agroforestry on soil health and maize productivity in the Rift valley, Ethiopia

The present study investigated the effects of Moringa stenopetala (Baker f.) Cufod. trees on soil physico-chemical properties and maize (Zea mays L.) grain yield in the Karfura watershed, located in the Rift valley of Ethiopia. A total of 36 composite soil samples and corresponding maize yield data were collected at three radial distances (1 m, 3 m, and 10 m) from the trunks of M. stenopetala trees across three altitudinal zones (low, mid, and high elevations). Soil samples were analyzed for texture, moisture content, bulk density, pH, total nitrogen (TN), available phosphorus (AP), organic carbon (OC), and electrical conductivity (EC). Maize grain yield was measured from plots established at the same radial distances around each tree. Results showed that soil bulk density increased significantly with distance from the tree trunk, whereas soil moisture, TN, AP, OC, and EC decreased. Maize grain yield was consistently higher under M. stenopetala canopies than in adjacent open fields. Elevation had a strong influence on soil and yield parameters: soil nutrient concentrations, moisture content, and maize yield all declined significantly with increasing altitude. These variations were likely attributed to microclimatic differences, reduced organic matter input, steeper slopes, and more intensive land use at higher elevations. Overall, the findings demonstrate the ecological and agronomic significance of M. stenopetala in smallholder farming systems. Scattered M. stenopetala trees enhance soil fertility and maize productivity, particularly in degraded landscapes. The study highlights the potential of indigenous parkland agroforestry systems as sustainable land management strategies for improving soil quality and strengthening food security. Future research should explore litter decomposition dynamics, soil microbial activity, carbon sequestration potential, and the long-term impacts of M. stenopetala orchard establishment on soil health and productivity.