Impact of Land Use Changes on Soil Erodibility in the Outer Himalayas

Abstract

Land use change hurts soil characteristics such as permeability, soil texture and aggregate stability, soil erodibility etc. which make soils susceptible to erosion and degradation. The outer Himalayan region is prone to large-scale soil erosion by water owing to the vast disparity in the slope gradient, undulating relief, largely mountainous joined with high-intensity rainfall and lithological characteristics of these rocks. Soil erodibility, one of the key factors affecting the rate of erosion can be estimated by using various soil erodibility indices. In examining erodibility indices across various land use changes, it was evident that both the clay ratio (CR) and modified clay ratio (MCR) escalated as land use shifts from forest to more disturbed environments. As we transit from forest to agriculture, these ratios increased and were even more marked in the transition from forest to wasteland. The erosional behaviour as per CR and MCR in agriculture land use transitions could be arranged in the order that forest < agriculture <builtup< wastelands. Among wasteland use transitions, the high CR and MCR indicated potential challenges in soil management, while the lower CR and MCR in transitions to agriculture and forest suggested more favourable soil conditions for these specific uses. The CR and MCR ratios indicated that the lower the ratio, the more would be the clay accumulation and lesser the erosion. This information is crucial for understanding the implications of land use changes on soil erosion and health and for guiding effective land management practices in diverse ecological settings.