Revised Slope Length Factor for the Universal Soil Loss Equation

ABSTRACT An analysis based on theoretical considerations and data interpretation was used in developing revised relationships for the slope length exponent for the Universal Soil Loss Equation. The analysis was based on the ratio of rill to interrill erosion and resulted in a general relationship between the slope length exponent and slope steepness. Parameters in the relationship are changed depending upon whether the ratio of rill to interrill erosion is expected to be low, moderate or high. Such conditions might be representative of rangeland or no-till seeding, normal seedbed conditions or highly disturbed conditions, respectively. For thawing soil conditions where rill erosion is dominant, an exponent value of 0.5 is recommended..