ABSTRACT

Forest soils in Ekiti state western Nigeria are destroyed due to agricultural activities. Information about the effect of land use on soil is important for soil sustainability and productivity. A study was conducted to investigate changes that may occur in the soil organic carbon content (SOC) and some selected soil physical properties due to conversion of forest to arable land. Six locations that were selected for this purpose include; Ona-Ara (Ll), Asin (L2), Ijesa Isu (L3), Odo-Oro (L4), Asaba (LS) and Osin (L6) in Ikole and Oye Local Government Area in Ekiti state, southwestern Nigeria, Soil parameters evaluated include particle size distribution, bulk density, moisture content, total porosity and soil organic carbon. Disturbed and undisturbed samples were collected from six locations at each of the forest and adjacent cultivated sites from depth 0-10cm and 10-20cm. The experiment was arranged as a 2 x2 x 6 factorial experiment for the factors land use, depth and location with three replication in completely Randomized Block Design. The result indicated 70, 41, 17, 67 and 33% decline in clay, silt, SOC, porosity and moisture content of the soil respectively. Bulk density increased by 31% while 26% increase was recorded in the sand fraction. Increase in sand fraction implies loss of fine fractions which might be attributed to selective erosion. At the two different depths, result shows that cultivation caused a significant decline in all soil properties. Interaction of location and land use showed that all the location were adversely affected by land use change, although in different degrees probably due to management system and inherent property of each locations. In conclusion, the study observed that cultivation of forest land resulted to degradation of soil organic carbon and physical properties which are crucial for sustainability and productivity.

Key words: Land use, Forest, Cultivated, Soil physical properties, SOC (soil organic carbon).