The Effect of Land Uses on Soil Erodibility (Index) and Soil Loss of the Keana Geological Sediments of Parts of Nasarawa State, Nigeria

Abstract

The effect of land uses on soil erodibility and soil loss of the Keana geological sediments of parts of Nasarawa State, Nigeria was investigated in this study. Geographic positioning system (GPS) was used to identify three land uses (agricultural, forested, and residential). Soil samples were collected from top soils at 0-30 cm depth using core sampler from 1 ha of each land use in 8 settlement communities (16 locations). Standard laboratory methods for soil analysis were followed for determination of Dispersion ratio, Erosion ration, Clay ratio and Modified clay ratio. Linear regression and correlation were used to determine the logical relationship between the erodibility index and corresponding soil loss. The soils from the study area were classified as sandy loam and sandy clay loam with high density, high permeability and porosity making them less vulnerable to shear stress. Dispersion ration (DR) modified clay ratio (MCR), Clay ratio (CR) and Erosion ratio (ER) where high, which suggests that soils from the study area are vulnerable to erosion at various degree of susceptibility.  Mean value of erodibility factor (K) and predicted soil loss of 0.0492, 0.0460 and 0.0357; 7.77, 7.20 and 5.48 tonnes/hectare/year  for agricultural, forested, and residential  lands respectively. The findings suggest that land uses influence the soil erodibility in the formation is in this order residential land > agricultural land > forested land use. The erosion class is ‘very low’ for forested (soils in this class have very slight to no erosion potential), ‘low’ (soil losses will occur) for agricultural and residential land uses respectively. These findings suggest that soil erodibility has been significantly influence by land use change in Keana geological sediment.