Predicting rainfall erosion losses: a guide to conservation planning

Abstract

The Universal Soil Loss Equation (USLE) enables planners to predict the average rate of soil erosion for each feasible alter- native combination of crop system and management practices in association with a specified soil type, rainfall pattern, and topography. When these predicted losses are compared with given soil loss tolerances, they provide specific guidelines for effecting erosion control within specified limits« The equation groups the numerous interrelated physical and management parameters that influence erosion rate under six major factors whose site-specific values can be expressed numerically. A half century of erosion research in many States has supplied infor- mation from which at least approximate values of the USLE factors can be obtained for specified farm fields or other small erosion prone areas throughout the United States. Tables and charts presented in this handbook make this information readily available for field use. Significant limitations in the available data are identified. The USLE is an erosion model designed to compute longtime average soil losses from sheet and rill erosion under specified conditions. It is also useful for construction sites and other non- agricultural conditions, but it does not predict deposition and does not compute sediment yields from gully, streombank, and stream bed erosion.