Evaluating the Role of Agroforestry in Soil Conservation in the Semi-Arid Zone of Niger State, North Central Nigeria

Soil degradation from wind and water erosion in the semi-arid zone of Niger State threatens agricultural productivity and food security for farming communities. Agroforestry systems have been advocated as ecologically appropriate interventions for reducing erosion and rebuilding soil fertility. This study evaluated the role of established agroforestry systems in soil conservation across six farming communities in the semi-arid zone of Niger State. Agroforestry plots integrating Faidherbia albida, Vitellaria paradoxa, and Parkia biglobosa with food crops were compared with adjacent monoculture fields. Soil samples were collected at 0 to 15 and 15 to 30 centimetre depths from both plot types and analysed for erosion indicators including aggregate stability, organic carbon, total nitrogen, bulk density, and available phosphorus. Runoff and soil loss were measured using erosion plot collectors installed in a subsample of plots. Results showed significantly greater aggregate stability, higher organic carbon, and lower bulk density in agroforestry plots compared to monoculture fields. Measured soil loss rates under agroforestry were 62 percent lower than from bare cropland during simulated rainfall events. Organic carbon improvement was greatest in plots with Faidherbia albida, which fixes nitrogen and drops its leaves during the cropping season. The study recommends scaling agroforestry adoption in Niger State's semi-arid zone through farmer field school programmes and targeted tree seedling distribution by the Agricultural Development Programme. Keywords: agroforestry, soil conservation, Niger State, semi-arid, erosion.