Evaluating the Effectiveness of Indigenous Soil and Water Conservation Practices in Reducing Runoff and Erosion in the Sahel Zone of Zamfara State, North West Nigeria

This study empirically evaluates the hydrological effectiveness of indigenous soil and water conservation (ISWC) practices used by Sahelian farmers in Zamfara State, located in Nigeria's North West geopolitical zone. Indigenous SWC practices including zai pit planting, half-moon catchments, stone bunds, and tied ridges have been practised by farmers across the West African Sahel with anecdotal evidence of success, but rigorous hydrological measurement of their effectiveness under Zamfara State conditions is largely absent, creating a gap between policy advocacy and scientific evidence. Using a runoff plot design, 15 runoff measurement plots (5 by 20 metres) were established on representative farm sites in Kaura Namoda and Talata Mafara local government areas, with each indigenous SWC practice replicated against a bare fallow control. Runoff volume and sediment concentration were measured for each rainfall event exceeding 10 mm throughout two wet seasons. Soil infiltration rate and surface storage capacity were measured at the beginning and end of each season. Findings revealed that zai pits and tied ridges produced the greatest runoff reduction (68 and 61 percent respectively) compared to the unprotected control. Sediment yield was reduced by 72 percent under half-moon catchments and by 65 percent under stone bunds. All ISWC practices significantly improved in-situ infiltration. In-season crop yields were 40 to 85 percent higher on ISWC-treated plots than bare fallow. The study provides empirical validation for ISWC scaling in Zamfara State and recommends integration of ISWC training into the Zamfara State agricultural extension curriculum. Keywords: indigenous soil conservation, runoff, erosion, Zamfara State, Sahel.