Effect of Topography on Soil Eredibility in Kakuuto Micro-Catchment, Uganda

Abstract

Soil erodibility is a property that determines the vulnerability of a soil to erosion processes. Interrill erodibility of 7 soil types, haplic Luvisols, haplic Acrisols, skeletic Luvisols, skeletic Acrisols, rhodic skelectic Acrisols, ferric Acrisols, ferri Rhodic Acrisols of Kakuuto micro-catchment of the Lake Victoria basin was measured, and its toposequence pattern investigated using a portable rainfall simulator in the field. Simulated rainfall of 7 mm/min was applied for 5 min on 0.25 by 0.25 m plots; 16 tests were run on each soil type, under 2 moisture regimes (dry and wet). Results indicated that there were 2 groups of no pairewise significant difference in interill erodibility: haplic Acrisols, haplic Luvisols, Rhodic skeletic Acrisols, and skeletic Acrisols, ferric Acrisols, ferri rhodic Acrisols and skeletic Luvisols (p=0.011) being the second. The first group was more eroded than the second. Significant differences (p=0.05) were observed along the toposequence on interrill erodibility with an increase towards the footslope. The footslope interrill erodibility was 4.13 × 10⁶kg/m²s while values of 1.05 × 10⁶/kgm⁴s and 1.74 × 10⁶/kg/m²s were observed at the upper and the middle landscape position; respectively.