Why the universal soil loss equation and the revised version of it do not predict event erosion well

摘要

The universal soil loss equation (USLE; Wischmeier and Smith, 1978) and its revised version (RUSLE; Renard et al., 1997) were developed to predict the long-term average annual erosion A from field-sized areas from six factors: R the rainfall-runoff (erosivity) factor, K the soil (erodibility) factor, L the slope length factor, S the slope gradient factor, C the crop and management factor and P the conservation support practice factor. The USLE/RUSLE model is often represented by the equation A = RKLSCP where R is the average annual sum of the event rainfall-runoff (erosivity) factor when this factor is given by the product of the kinetic energy of the rainstorm E and the maximum 30 min rainfall intensity I_30, L = S = C = P = 1.0 when the area is bare fallow on a 9% slope that is 22.13 m long with cultivation up and down the slope, and K is the average annual soil loss per unit of R when L = S = C = P = 1.0.