Landuse and sediment yield in parts of South Western Nigeria

Abstract

12, 3rd order drainage basis were selected from an area of similar geology (quartzite-quartz schists) and relief (ridge and valley topografy) in parts of Central Western Nigeria,noted for upland rice cultivation which has involved the virtual transformation of a dry rainforest into contiguous farmlands. The basins were monitored for one year with emphasis on runoff and sediment yield. Six basins had 55-81% forest cover while 6 had 56-89% farm coverage. All the streams were perennial. The farmed basins had significantly higher values of specific suspended sediment yield than the forested basines, while values of specific solute load from the two sets of basins were not significantly different. The mean denudation rate was significantly higher in the farmed basins.