Predicting Rainfall Erosion Losses With The Universal Soil Loss Equation

The USLE equation provides techniques for numerically evaluating effects of climate, soil properties, topography, crop-productivity level, time and method of seeding, crop sequence, residue management, special conservation practices, and other pertinent variables that effect soil erosion. It is a required element in farm and ranch plans used to qualify for USDA assistance programs; it is an invaluable tool for natural resource inventories carried out in the United States; it has been the basis of economic analyses related to agriculture; and it has been an important element in analyses dealing with assessment and control of surface water quality.
USLE has become the major conservation planning tool which is used in the United States and other countries in the world.
The USLE was developed from erosion plot and rainfall simulator experiments. The USLE is composed of six factors to predict the long-term average annual soil loss.
A = R*K* L S* C* P
Where: A=The average annual soil loss, R= the rainfall erosivity factor, K= the soil erodibility factors, the topographic factors (L and S) L = slope length factor, S = slope steepness factor, and the cropping management factors (C and P) C = cover-management factor, and P = supporting practices factor

Useful USLE Links
Rainfall Erosivity Factor Calculator for Small Construction Sites
San Diego State University Online USLE
US Department of Agriculture
USDA-Agriculture Research Service
USLE Database