RUSLE

RUSLE, the Revised Universal Soil Loss Equation, is an empirical model used to estimate long-term average annual soil loss caused by rainfall-erosion processes on cultivated land. It is designed to support soil conservation planning by providing a quantitative basis for comparing erosion under different land uses and management practices.

The model expresses predicted soil loss A as A = R × K × LS × C × P, where:

- R is the rainfall erosivity factor, representing the effect of rainfall intensity and amount on erosion potential.

- K is the soil erodibility factor, reflecting the inherent susceptibility of soil to erosion based on properties such as texture, structure, organic matter, and permeability.

- LS combines slope length (L) and slope steepness (S) to account for topographic influence on erosion.

- C is the cover-management factor, capturing how vegetation, residue, and tillage practices reduce erosion.

- P is the support practices factor, indicating the effect of practices such as contouring, terracing, and stripcropping on erosion.

RUSLE is widely applied in watershed and land-management planning, soil-conservation design, and comparative assessments of erosion-control measures. It requires data on rainfall energy, soil properties, land slope, vegetation/management, and conservation practices, typically using a geographic information system (GIS) for spatial analysis. Outputs are units of soil loss (often tons per hectare per year) that can inform practice adoption and policy decisions.

Limitations include its empirical basis, regional calibration needs, and focus on sheet and rill erosion rather than gully or mass wasting processes. It is best suited for long-term, average conditions on cultivated lands. RUSLE has a successor version, RUSLE2, which offers broader GIS integration and updated process representations.