Soil erodibility assessment of laterite dominant sub-basin watersheds in the humid tropical region of India

Abstract

Sub-basin prioritization is an essential aspect of watershed development initiatives as a part of the sustainable management program for natural resources. The present work aims to analyse the soil erodibility at sub-basin scale in the Pathro River Basin area of Jharkhand, India. Degradation of land resources is multifaceted, and its severity leads to soil detachment, thus rendering it a complex and interlinked system. Sixteen closely correlated morphometric attributes of the erosion process are considered for prioritizing watersheds by applying the frequency ratio (FR) method. This work assigns Support Vector Machine (SVM) algorithm to evaluate the existing soil risk condition with the help of twelve soil erosion influencing geo-environmental factors at the sub-basin area. Soil samples were examined using scanning electron microscopy with energy dispersive x-ray analysis (SEM-EDX) to acquire the micro-graphic and physical condition of dominant soil forming minerals and their influences to develop susceptibility of peds to erode. The prioritisation results from both approaches show a reasonably similar output, identifying nine sub-watersheds as very high soil erosion-prone, while four sub-watersheds are recognised as low-risk. Field observation reveals that lowering of plunge pool and head retreat are dominant processes of gully extension in very high to high sub-basin prioritization areas. The final output provides a comprehensive platform for the urgency of policy interventions to minimize erosion risk and ecological damage in prioritized areas of Pathro River Basin, Jharkhand.