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United States Department of Agriculture

Agricultural Research Service

USLE

About the Universal Soil Loss Equation

The Universal Soil Loss Equation (USLE) is hailed as one of the most significant developments in soil and water conservation in the 20 thcentury.   It is an empirical technology that has been applied around the world to estimate soil erosion by raindrop impact and surface runoff.   The development of the USLE was the culmination of decades of soil erosion experimentation conducted by university faculty and federal scientists across the United States.

USLE as a complete technology was first published in 1965 in USDA Agriculture Handbook 282.   An updated version was published in 1978 in Agriculture Handbook 537.   The Revised Universal Soil Loss Equation (RUSLE), which is a computerized version of USLE with improvements in many of the factor estimates, was initially released for public use in 1992.   Work is continuing on a further-enhanced Windows version of the software, known as RUSLE2.

Universal Soil Loss Equation A = R K L S C P

The USLE was developed at the USDA National Runoff and Soil Loss Data Center at Purdue University in a national effort led by Walter H. Wischmeier and Dwight D. Smith. The USLE is based on extensive erosion data from studies throughtout the USA, and provides a quick approach to estimating long-term average annual soil loss (A). The equation is comprised of six factors:

  • R - rainfall and runoff;
  • K - soil erodibility;
  • L - slope length;
  • S -slope steepness;
  • C - cover and management;
  • P - support practice.
USLE was the first empirical erosion equation that was not tied to a specific region of the United States, thus the title "Universal" Soil Loss Equation.

The USLE has beem used in more than 100 countries to guide connservation planning, assess soil erosion for conservation policy development, and estimate sediment yield. It has helped to save millions of tons of soil, thus helping to the feed the world's population, and to protect the environment from sediment produced by soil erosion.

The National Soil Erosion Research Lab, located in West Lafayette, Indiana, serves as the repository for the USLE data which is made available via this web site.  The data is available in three different sets: Storm Data, Soil Loss and Runoff, and Site Specific Data.  These sets are taken from various locations from all over the United States. 


Storm and Runoff, Soil Loss Data

USLE data can be downloaded from the following link: USLE Data Download Page

Cultivation Dates for Fallow Plots and Selected Sites

This is a very selective data set. It contains cultivation dates for fallow plots at the following locations: Watkinsville, Georgia; Castana, Iowa; Clarinda, Iowa; Independence, Iowa; and Morris, Minnesota. There is data from 1933 to 1970.

Cultivation Data as text file
Culitvation Data as Excel Spread Sheet

USLE History

The following link is short history of the USLE. History of the USLE

USLE Documents

USDA-Agriculture Handbook (AH) 537 (9MB)

USDA-Agriculture Handbook (AH) 282 (6.3MB)


Last Modified: 1/29/2009