Investigating spatial contribution of land use types and land slope classes on soil erosion distribution under tropical environment

Increasing land occupancy for farming without conservation principles, particularly in the Indonesian island of Java, is resulting in a severe erosion problem. This study investigated the characteristics of soil erosion and the spatial contribution of land use and land slope on erosion under the tropical climate in a watershed scale. The Revised Universal Soil Loss Equation model with locally source parameters assessment in a Geographic Information Systems was used for soil erosion calculation. Erosion (in unit t ha−1 yr−1) and land slope were classified into five classes. Meanwhile, the types of land use were classified into six types. The results showed critical erosions largely occurred in steeply sloping areas, where the main source of erosion was farmland. We found that land cultivation practices have more potential to increase soil erosion in slopes steeper than 15%, and the large amount of erosions were generated from some small areas of the watershed. This study also demonstrated the land slope and erosion correlation equations for five land slope classes, which detected that the largest effect of land slope on erosion was recognized in the low sloping areas. These findings indicated erosion studies in various land slope zones were necessary to understand the uniqueness of erosion in specific land slope areas. The present study provides a fundamental knowledge of land slope zonations for erosion control planning particularly in high-risk erosion areas.