Soil erosion assessment in the hilly terrain of Arunachal Pradesh, India through integrated approach of RUSLE and geospatial technology

Abstract

Soil erosion is a major challenge in the north-eastern Himalayan region, due to the fragile nature of the soil and ecosystem, high intensity of rainfall and faulty agricultural processes. To understand and asses the causes, measure the impact of soil erosion and find suitable correction measures, a study was undertaken at Diyun block, Changlang district of Arunachal Pradesh. For this study, the RUSLE method was used and thematic layers were extracted using remote sensing and soil data in the GIS environment. The block was divided into six broad landforms, viz., low amplitudinal hills (LAH), interhill valley, upper piedmont, lower piedmont, upland and floodplain. Under these landforms, soil series were identified viz., Shillongphar, Dimapur and Kamayakapur, Balupathar, Shayambhasti and Deba block, Modoi and Udaipur, respectively. It was observed that LAH (Shillongphar series), the inter-hill valley (Dimapur and Kamayakapur series) and the upper piedmont (Balupathar series) are more prone to erosion. However, soil erosion in floodplain (Udaipur series) was eroded extremely severe, which is located near to the river side. The area under soil loss falling in category of the severe to extremely severe class was 6450.16 ha (29.71% of TGA), whereas the soil losses of block follow under very slight category was of 11733 ha (54.06 % of TGA), extremely severe 3369 ha (15.52% of TGA), severe 1632 ha (7.52% of TGA), very severe 1448 ha (6.67% of TGA), slight 1218 ha (5.61% of TGA), moderate 893 ha (4.12% of TGA) and moderately severe 680 ha (3.14% of TGA). The soil erosion was found to be higher near to the 1st and 2nd order streams, where soil conservation measures are necessary to check soil erosion. It has been proven that the use of geospatial technologies in combination with RUSLE is a comprehensive approach which helps in the spatial assessment of soil erosion for better resource planning.