Soil Loss Estimation through USLE and MMF Methods in the Lateritic Tracts of Eastern Plateau Fringe of Rajmahal Traps, India

Abstract

Laterites of Birbhum district are indentified as the ‘low-level laterites’ of ‘Rarh Plain’ of West Bengal and these are very much prone to severe soil erosion (mainly surface and sub-surface water erosion) in the monsoon season (June - September). Laterites and lateritic soils (locally named ‘Kankara’) of Caniozoic upland (adjoining areas of Rampurhat I block, Birbhum and Shikaripara block, Dumka- the study area), are the direct result of monsoonal wet-dry type of morpho-climatic processes and further laterisation of fluvial deposited materials (formation of surface duricrust) which was coming from Rajmahal Hills of eastern Chotanagpur Plateau (Jharkhand) in late Pleistocene. Such type of vermiform laterites is shaped and dissected by numerous gullies and ravines, giving birth of badland topography (locally named ‘Khoai’) of both degradation and aggradation processes. Before the soil conservation practices it is helpful if the assessment of soil erosion can be transformed into a statement of how fast soil is being eroded. The estimation of rate of annual soil loss is required in that case, because we must have to predict soil loss through effective models under a wide range of conditions. In this study the entire assessment is focused on the application Universal Soil Loss Equation (USLE) and Morgan, Morgan and Finney (MMF) methods in the soil loss estimation of sample slope segments, and relative comparison and suitability of both methods in the precise estimation of predicting soil loss.

Keywords: Laterite, Gully, Rainsplash, Overland flow, USLE and MMF