About RUSLE 

Research on soil erosion and its effect on agricultural productivity started in 1930s. During 1940 and 1956, research scientists began to develop a quantitative procedure for estimating soil loss in the Corn Belt in the United States. Several factors were introduced to an early soil loss equation, in which slope and practice were primarily considered. It was recognized that a soil loss equation could have a great value for farm planning and the Corn Belt equation could be adapted for other regions. In 1946, a group of erosion specialists held a workshop in Ohio to reappraise the factors previously used and added a rainfall factor. U.S. Department of Agriculture, Agricultural Research Service (ARS) established the National Runoff and Soil Loss Data Center at Purdue University in 1954 to locate, assemble, and consolidate all available data throughout the United States. More than 10,000 plot-years of basic runoff and soil loss data were then collected from U.S. federal-state cooperative research projects in 49 U.S. locations. 

Based on the data assembled at the Data Center and previous studies, Wischmeier, Smith, and others developed the Universal Soil Loss Equation (USLE). An Agriculture Handbook (No. 537) describing USLE was published in 1965 and revised in 1978. With a widespread acceptance, USLE has become the major conservation planning tool which is used in the United States and other countries in the world.

With additional research, experiments, data, and resources become available, research scientists continue to improve USLE, which led to the development of Revised Universal Soil Loss Equation (RUSLE). RUSLE has the same formula as USLE, but has several improvements in determining factors. These include some new and revised isoerodent maps; a time-varying approach for soil erodibility factor; a subfactor approach for evaluating the cover-management factor; a new equation to reflect slope length and steepness; and new conservation-practice values (Renard, et al., 1997). A new Agriculture Handbook (No. 703) which describes RUSLE in great detail was published in 1997 by the U.S. Department of Agriculture. 

A  =  R * K * LS * C * P