Tillage Effects on Erosion and Sediment Sizes

ABSTRACT SOIL erosion can be described by the factors of the well known USLE that is extensively used to predict erosion from farmland. The C factor of this equation represents the cropping system and tillage management by which a farmer can most easily control erosion. This research was concerned with tillage timing and frequency which contributes to the value of the C factor. Using a rainfall simulator, evaluations of the treatments were made from measurements of runoff, soil loss and soil particle sizes (both dispersed and undispersed). No difference in the measurements could be attributed to tillage performed 0, 30, and 60 days before a final smoothing operation immediately before testing with the rainfall simulator. However, rainfall applied 30 days after the first test without further tillage resulted in 17% greater runoff, 39% greater soil loss, and twice as much aggregated silt and clay in the sediment as measured during the first test. These results demonstrated that differences in effects of tillage are relatively small but differences in runoff, soil loss, and sediment sizes are large due to wetting and drying with time after tillage.