Rangeland Erosion Measurements for the USLE

A rotating-boom rainfall simulator was used on sagebrush and shadscale rangeland sites in southwest Idaho and north-central Nevada to obtain USLE soil erodibility, K, and cover-management, C, factor values. A good relationship, r^ = 0.89, was obtained between measured soil loss from tilled simulator plots at four different sites and predicted soil loss using the USLE soil erodibility nomograph. However, relationships between soil loss predictions using a cover-management subfactor procedure and soil loss measurements using the rainfall simulator were in poor agreement, r^ = 0.27, for all vegetated plots combined. Soil loss from simulation on plots ungrazed for ten years was consistently less than predicted, and plots on one site clipped of all standing vegetation produced more soil loss than predicted. Thus, the variability in predicted soil losses from sagebrush rangelands indicates a need for more accurate quantification of cover and management conditions.