A Comprehensive Review of Rainfall, Topography, and Soil Dynamics Shaping Erosion in Northeast India’s Vulnerable Highlands

Abstract

Soil erosion is a critical environmental challenge in Northeast India, significantly affecting agricultural productivity, water security, and ecosystem stability. The region’s hilly landscapes, fragile soils, and monsoon-dominated rainfall patterns make it highly vulnerable to erosive processes. High-intensity, short-duration rainfall events generate rapid surface runoff, mobilizing soil particles and accelerating land degradation. Continuous topsoil loss leads to nutrient depletion, reduced soil fertility, lower crop yields, and sedimentation in rivers and reservoirs, while also threatening biodiversity and the resilience of rural communities reliant on rainfed agriculture. This review synthesizes recent literature on the key factors influencing soil erosion in Northeast India, focusing on rainfall erosivity, topography, and soil characteristics. Rainfall erosivity, determined by the intensity and kinetic energy of precipitation, is a primary driver of soil detachment and sediment transport, with seasonal and extreme events producing spatially variable erosion patterns. Topography, including slope length and steepness, regulates water accumulation, flow velocity, and sediment yield, contributing to heterogeneous erosion risks across micro-watersheds. Soil properties, such as texture, structure, infiltration capacity, and organic matter content, mediate soil susceptibility, with clay-rich soils exhibiting higher runoff and sediment loss compared to better-drained sandy loam soils. Integrated, multi-factor analyses combining rainfall, topography, and soil characteristics enhance predictive accuracy and identify erosion-prone areas more effectively than single-factor studies. GIS-based modeling, remote sensing, and field-scale assessments provide critical insights for prioritizing conservation interventions. The review emphasizes that targeted, site-specific soil and water management strategies, such as slope stabilization, soil cover improvement, and water retention measures, are essential to mitigate erosion, sustain agricultural productivity, and protect fragile ecosystems. Understanding the complex interactions among climatic, topographic, and edaphic factors is fundamental to developing adaptive and sustainable soil conservation practices in Northeast India.