INTERRILL SOIL-EROSION AS AFFECTED BY TILLAGE AND RESIDUE COVER

No-till cropping systems are effective in reducing soil erosion. The objective of this study was to determine whether high infiltration rates and low runoff and soil loss under long-term, no-till conditions in loessial regions of the Midwest US result from both the well-structured, porous condition of the soil and the protective cover of crop residue or primarily from residue cover. Soil loss, runoff, and infiltration were measured using a rainfall simulator on interrill erosion plots with and without residue cover on a conventional and two no-till systems in central Illinois. For both conventional till and no-till conditions, removing surface residue significantly decreased infiltration rates and increased soil loss. Tilling the no-till surface while maintaining an equal surface cover as with the no-till system slightly increased interrill erosion. Removing residue on a no-till system, however, increased soil loss significantly. A no-till soil condition without adequate residue cover will seal, crust, and erode with extremely high soil losses following surface drying.