The Effect of Slope Gradient on Particle Size Distribution of the Splashed Soils

Abstract

Soil erosion involves two interrelated processes of detachment and transportation of soil material. The detachment of soil material caused by raindrop impact is first and foremost a function of soil-dependent process. Benue State is a predominantly agrarian State, but is ravaged by soil erosion menace, particularly the removal of the top nutrient rich soil. This paper examined the effect of slope gradient on particle size distribution of splashed soils in Makurdi, Benue State. Data was collected on splashed sediments in an experimental station in Benue State University, Makurdi for some selected months of April, June, August and October in 2007. Sediment collectors were attached to 4 soil trays placed at an angle of 5, 15, 25, and 35 degrees to collect splash yield at the selected months upslope and downslope sides. The soils were oven dried, weighed and analysed for textural characteristics. The result showed that at the beginning of the rainy season in April, the sandy nature of the original soil was reflected in the particle size distribution of the splashed soil. Sand particles dominated at virtually all the slopes, both at the downslope and upslope section. The result also showed that there was dispersion, sorting and separation of soil aggregates with silt and clay
dominating the splashed soil particularly as the rain progressed. The implication is that if the soils in the study area are exposed, the soil surface would be enriched by sand and stones resulting in breakdown of soil structure.