Soil Survey and Land Evaluation Studies of A Proposed Irrigation Project Site at Ejigbo Dam, Ejigbo, Osun State, Nigeria

An intensive soil survey and land use evaluation study of a proposed irrigation project site at the Ejigbo Dam in Ejigbo, Osun State, south-west Nigeria, was carried out. The major objective was to identify the soil types to obtain information about their productivity under irrigation. A rigid grid system of survey was adopted. Five soil types were identified on the site along the toposequence from the upper part of the slope to the valley bottom. These are: Plinthic Ustropept; Plinthic Tropustalf; Plinthic Ustropept; Plinthic Tropustalf and Typic Plinthaqualf. A total of about 30.6% of the available 75 hectares of land is a lateritic area due to excavation, construction work (for buildings or road construction). About 22.3% of the land has sandy-loam top soil overlying slightly sticky sandy clay loam with plinthite in the subsoil. Irrigation is possible on these soils because infiltration rates are high enough at the surface. However, the plinthic nature of the subsoil will not allow the use of much water per time as it may result in waterlogging. The native nutrients are not much in concentration and should be boosted over time with fertilizer and/or organic manure application. Crops like yam, cassava, maize, sorghum, upland rice, vegetables like pepper, leaf-vegetables, okra, garden eggs, etc. can be grown on these soils.