Assessment of Agricultural Land Use Systems for Soil Fertility Maintenance

Land is the most important endowment in nature, providing livelihood in both the agricultural and non-agricultural sectors. However, most areas of land previously developed from tropical rainforest have been degraded as a result of land misuse with nutrient mining and soil degradation presently considered as problems in arable farms. Hence, the extent to which land for crop production influences soil properties need to be studied to greater details due to variations in soils by location. The objective of the study is to investigate the effect of agricultural land use systems on the soil physical and chemical properties. Three representative fields with three replicates each which have been in active use for last 5 years were selected from each agricultural land use types: Cultivated (07.31° N 05.12° E 360.0 M), Agroforestry (07.31° N 05.21° E 373.5 M) and Grazing land (07.29° N 05.35° E 355.0 M). Five soil subsamples were collected from the depths of 0-20 and 20 - 40 cm each in a radial sampling. The data was subjected to analysis of variance (ANOVA) using Statistical Analytical System (SAS) and the means were separated using Duncan’s Multiple Range Test (DMRT) at P<0.05 significant level. The mean values of soil chemical properties are highest in the agroforestry land followed by cultivated and then in the grazing land. Grazing land shows the highest bulk density of (1.87 g/cm3), cultivated (1.30 g/cm3) and then agroforestry (1.24 g/cm3) with same trends recorded in particle density across the land use. The soils significantly responded to changes in land use systems through salient soil features which constitute soil properties governing soil fertility and productivity. Such human-induced change is not limited to surface soils but also the subsurface soils and has remarkable implication for ecosystem quality and productivity of the traditional low-external-input agriculture in the study area.