Soil‐Erodibility Evaluations for Soils on the Runoff and Erosion Stations

Abstract

Abstract The universal soil‐loss estimating equation introduced by Wischmeier is: A = R K L S C P where A is estimated soil loss, R is the rainfall‐erosion index, K is the soil‐erodibility factor, and L, S, C, P are factors for length and percent slope, cover, and mechanical conservation practices, respectively. The soil‐erodibility factor (K) is defined as the average soil loss per unit of the erosion index (R) from continuous fallow on a plot 72.6 feet long on a 9% slope. The value of this factor was approximated for 20 soil types represented on the U. S. Department of Agriculture runoff and erosion research stations located in the eastern half of the United States. The estimated values were computed from the plot data, using those plots whose conditions most closely approximated base conditions of cover and geometry. Observed soil losses from cropped plots were adjusted to fallow conditions by use of previously published numerical values of C and P. The resulting table of K values provides a list of bench‐mark values for estimating the erodibility of other soils.