A formula used to estimate erosion rates by considering climate, soils, and topographic conditions at a site, as well as any degree to which the use and management of the soil reduce erosion. It is being replaced by a revised universal soil loss equation.

an equation developed to predict soil losses due to runoff from specific field areas in specified agricultural cropping and management systems. The equation consists of a rainfall and runoff factor, soil erodibility factor, slope-length factor, slope-steepness factor, cover and management factor, and support practice factor.

An erosion model designed to predict the long-term average soil losses in runoff from specific field areas in specified cropping and management systems. The equation is: A = RKLSCP where A = Computed soil loss per unit area R = Rainfall and runoff factor K = Soil erodibility factor L = Slope-length factor S = Slope-steepness factor C = Cover and management factor P = Support practice factor The NRI calculations use location-specific data for the field in which the NRI sample point falls or that portion of the field surrounding the point that would be considered in conservation planning.