Effects of Crop Canopy and Residue on Rill and Interrill Soil Erosion

ABSTRACT A rainfall simulation study with slope length simulation by flow addition was used to determine the effects of crop canopy and residue on rill and interrill soil erosion. An equation having a constant term for in-terrill erosion and a linear term with slope length for rill erosion was found to be applicable to the situation where clear water is added at the upper end of a small plot to simulate increased slope length. It was found that a coefficient of rill erodibility was related to surface residue cover and that this relation was little affected by crop canopy for one soil but was reduced by crop canopy for another soil. The effects of crop canopy on interrill soil erosion were not independent of the soil type. The study results were applied to determine the relationship of C values for the Universal Soil Loss Equation to crop residue cover for various slope lengths. The relationships were generally independent of slope length but varied with the soil and/or slope.