RUNOFF AND SOIL LOSS AS INFLUENCED BY TILLAGE AND RESIDUE COVER

To gain a better understanding of the interactions between soil detachment, transport capacity, and residue cover, and USDA programmable rainfall simulator was used to erode plots created on established and newly created ridge-till areas of less than 1% slope with and without residue cover. A control of conventional moldboard pow-spring disk was also included. Results showed that for all treatments, ridge sideslope erosion was three to four times greater than total soil loss, suggesting that transport capacity was the limiting factor. For most runs no significant difference in soil loss was measured between ridges of different ages. The presence of residue decreased soil loss to one-sixth or one-seventh on older ridges and to one-half on new ridges. Location of residue was more important than the total amount of residue. Residue placed only on the furrow bottom was as effective in reducing soil loss as residue placed over the entire ridge and furrow, while residue placed only on the ridge side-slope did not reduce soil loss significantly from treatments without residue.