ABSTRACT
This study involved analysis of soil samples of the watershed of the Iyada River in Ogwashi Uku Forest Reserve, Delta State Nigeria. The aim was to determine the effect of the vegetative cover of Tectona grandis (Teak) and Gmelina arborea (Gmelina) on the watershed as potential nutrient and fertility sources for the river while acting as an ecological fort against possible sheeting off of the soil surface to fill the river’s water catchment corners, and reshape its channels which could eventually endanger its sustainability. Soil samples were collected at five depth ranges ( 0-30, 30-59, 59-79, 79-99 and 99-150 cm) in the reserve to determine the particle size distribution, bulk density, porosity, moisture content, organic carbon, total nitrogen, exchangeable acidity and cat ion exchange capacity. Results revealed that soil organic carbon, calcium and phosphorus accumulated most at the 0-30cm and 30-59cm depths. However, the concentrations of these elements decreased significantly (P < 0.05) with depth. Hence loss of soil organic carbon and phosphorus can be minimized through less intensive cultivation practices of the watershed. |
