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United States Department of Agriculture

Agricultural Research Service

Title: A Single, Continuous Fuction for Slope Steepness Influence on Soil Loss

Author
item Nearing, Mark

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 26, 1996
Publication Date: N/A

Interpretive Summary: Soil erosion depends on many factors, the most important of which are climate, topography of the land surface, soil type, and land use and management. This study presents a mathematical relationship for the effect of slope steepness of soil erosion. It is unique in that for the first time ever, a single equation is presented which is useful and valid for slopes ranging from flat up to 60 percent grade. The equation will be useful to soil conservationists who advise farmers on developing farm conservation plans to combat soil erosion in their fields.

Technical Abstract: Recently proposed relationships for the effect of slope steepness on soil loss by water are linear functions of the sine of the slope angle. The Revised Universal Soil Loss Equation (RUSLE) uses two such functions: one for slopes less than 9 percent and another for slopes greater than 9 percent. Recent research indicates that yet a different linear function is necessary for slopes greater than approximately 22 percent. The objective of this study was to develop a single slope steepness function which is representative of the data for all slopes. The resultant equation takes the form of a logistic function. It closely follows the RUSLE relationships for the slope steepness factor for slopes up to 25 percent, and also fits existing data for slopes greater than those from which the RUSLE relationships were derived.

Last Modified: 4/17/2014
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