Assessing the Impact of Topography on Soil Erosion in Agricultural Areas Using UAV and GIS-Based Analysis

Abstract

Soil erosion is a critical environmental issue in mountainous agricultural areas such as the Lojing Highlands, where intensive agricultural activities accelerate soil degradation. Topographical factors such as slope, elevation, and aspect play a significant role in determining the rate of soil erosion, which in turn affects soil stability and agricultural productivity. This study investigated the influence of topographical factors (slope, aspect, and elevation) on soil erosion by integrating UAV photogrammetry and GIS analysis. High-resolution UAV images are processed in Agisoft Metashape to produce orthophoto and Digital Elevation Models (DEMs), while topographic parameters are extracted using ArcGIS Pro. Results showed that slopes greater than 15° (15-25%) had a high risk of erosion, with slopes exceeding 45% recording the most critical soil loss due to rapid surface flow. The south-facing slope has a 30% higher erosion rate than the north-facing slope due to its lower vegetation cover. The integration analysis of topographic parameters using GIS identified the risk zone with 85% accuracy, as validated by Ground Control Points (GCPs) and RMSE analysis. The study suggests focused management strategies, such as bioengineering (utilizing vetiver) for slopes exceeding 25° and agroforestry in southern regions, as well as enhancements to Sustainable Development Goals 2 (Zero Hunger) and 15 (Life on Land). This study is the first to integrate UAV-derived slope analysis in the Lojing Highlands by offering a scalable model for tropical upland erosion monitoring. This approach proves to be an efficient method for soil erosion monitoring in tropical upland agricultural landscapes.