Rill Erosion as Affected by Incorporated Crop Residue and Seasonal Consolidation

Afield study using artificial rainfall and added inflow was conducted to investigate the effects of incorporated-crop residue and tillage condition on rill erosion. Cornstalk residue was incorporated at rates of 0, 1 120, 2 240, and 4 480 kg/ha. The experiments were conducted just after incorporation, and 30 and 60 days following incorporation. Just after incorporation, rill erosion rates were significantly reduced 75 and 40%, at inflow rates of 9 and 69 L/min, respectively, for the 4 480 kg/ha rate compared to the zero residue rate. Rill erosion was significantly greater for the first experimental run on each furrow compared to experimental runs 30 and 60 days later. For a majority of furrows, the eroded channel shape produced by the first experimental run was essentially unchanged during later runs. An empirical factor was developed from the data to express the relative effect of incorporated-crop residues on rill erosion. This factor was a decreasing exponential model with a decay coefficient value of 0.000277. An empirical factor was also identified to express the combined relative effects of prior erosion, lack of disturbance, weathering, and wetting and drying on rill erosion. This factor was a decreasing exponential model with a decay coefficient value of 0.046. The decay coefficients were developed for these study conditions. These coefficient values may vary with a number of factors such as residue type, soil, and other site specific conditions.