Impact of Land Use Types and Soil Depths on Selected Soil Properties in Igboora, Nigeria

This study was carried out to evaluate the impacts of land-use types at different sampling depths on some selected soil properties within the Oyo State College of Agriculture and Technology, Igboora, Nigeria. The different land-use types were a woodlot, Cajanus cajan plot, nursery plot, vegetable plot, and cassava plot. Soil samples were collected from the land-use types at two depths (0-20 cm- topsoil; and 20-40 cm- sub-soil) in three replicates. Data collected were subjected to analysis of variance using Genstat statistical package and means separated using Least Significant Difference (LSD) at 5 % level of probability. The results show that in both the topsoil and sub-soil, particle size distribution, pH, organic carbon (OC), total N (TN), available P and exchangeable K were significantly different amongst various land use types and soil depth. The highest proportion of sand (92.10 %) was recorded in the woodlot while the lowest value (85.60 %) was found in the cassava plot. The highest proportion of silt (7.10 %) was recorded in the cassava plot while the lowest value (2.60 %) was observed in the woodlot and vegetable plot. Clay fraction was highest in cassava (7.30%) and lowest in nursery and C. cajan plots (4.80 %). The values of sand, silt, and clay in the topsoil are 91.20, 3.20, and 5.60 %, respectively while it is 88.40, 5.60, and 6.00 % for sand, silt, and clay in the sub-soil. Results obtained also showed that the pH value was highest (7.42) in the vegetable plot while the lowest value (6.22) was recorded in the cassava plot. This trend was observed for OC, TN, P, and K in the vegetable plots. The values recorded are 1.23 %, 0.10 %, 20.73 mg kg-1 and 0.36 cmol kg-1 for OC, TN, P and K, respectively. The impact of sampling depth on pH, OC, TN, and K revealed that they reduced with depth. On the contrary, P values were observed to increase with the sampling depth. This investigation thus revealed that land-use types and sampling depth greatly influenced soil properties in this area and recommends agronomic practices that will boost the organic matter contents as well as the nitrogen level of these soils.