Revised Universal Soil Loss Equation

The Revised Universal Soil Loss Equation (RUSLE) is an upgrade of USLE that is land use independent. It can be used on cropland, disturbed forestland, rangeland, construction sites, mined land, reclaimed land, military training grounds, landfills, waste disposal sites, and other lands where rainfall and its associated overland flow cause soil erosion. RUSLE was first introduced in the USDA Soil and Water Conservation Service in 1993. RUSLE maintains the same empirically based equation as USLE to compute sheet and rill erosion as follows: A=RKLSCP where A is computed soil loss, R is the rainfall-runoff erosivity factor, K is a soil erodibility factor, L is the slope length factor, S is the slope steepness factor, C is a cover management factor, and P is a supporting practices factor.

The major changes compared to USLE are in the values given for erosion as modified by vegetative cover and better calculations of the slope (LS) factors, as well as more advanced computerization.RUSLE gives more credit to the ability of surface residues to reduce erosion, as well as residues incorporated in the soil near the soil surface. Where USLE assumed that runoff was uniform over the catchment, RUSLE takes better into account that some runoff is channeled into rills and gullies. RUSLE also captures better than USLE that long rains can saturate the soil, leading to reduced intake and greater erosional runoff. In contrast with USLE, RUSLE can handle converging and diverging terrain and considers areas with net sedimentation.

An additional change incorporated in the RUSLE is to account for rock fragments on and in the soil. Rock fragments on the soil surface are treated like mulch in the C-factor, while K is adjusted for rock in the soil profile to account for rock effects on permeability and, in turn, runoff.