Spatial Prediction of Soil Erodibility Indices of the Sensitive Landscape of Bengkulu Watershed, Indonesia

Abstract

Soil erodibility index (K) is a complex concept and it is influenced by many soil properties, which can reflect the soil resistance to erosion. The K index indicates soil aggregate resistency to disperse and particle transported by rainfall. Higher the erodibility index, the soil is more susceptible to erosion or in reverse. This study was aimed to show spatial feature of soil erodibility index in the fragile landscape of Bengkulu watershed conducted from July to November, 2021. Spatial analysis used some map and Landsat 8 OLI satellite imagery and ArcGIS version 10.3. The analysis depicted spatial distribution of soil textures, soil structures, soil organic matter contents, soil permeabilities and soil erodibility indices. Actually, soil organic matter content in the hilly range and undulating areas in the upper part of the watershed are categorized moderate to very high classes, however, soil texture classes in the upstream dominantly are covered by sandy loam, and loamy sand. Soil aggregate formation through the soil organic matter and soil texture binding has composed the fine and very fine granular soil structures in the upper part and in the middle part of the watershed. In the upper part and in the middle part of the watershed landscape, in fact, soil permeabilities are classified as from moderate to fast. Overlying the all inherit soil attributes, in short, the soil erodibility indices in the fragile landscape of Bengkulu watershed are not prone to precipitation detachment causing soil erosion and soil productivity deterioration.