Evaluation of Wild Oat Straw as a Soil Erosion Retardant Using Simulated Rainfall1
- Michael J. Singer and
- John Blackard2
Soil cover is recognized as an important factor in soil erosion control. This study was made to determine the qantitative relationship between cover percent for one cover type and soil loss under simulated rainfall. Data from this experiment are used to calculate a cover coefficient for wild oat (Avena barbata Brot.) straw similar to the “C” factor in the Wischmeier Universal Soil Loss Equation (USLE). The R, K, L, S, and P factors were kept constant during the experiment.
A rainfall simulator was used in the laboratory to produce 30 min rainfall events of 76 mm/hour (3 in/hour) intensity on soil material at 9% slope. Under these conditions, wild oat straw significantly reduced sediment loss at cover levels of 50% or more. A significant reduction in runoff volume was observed for cover percentages exceeding 90%. A parabolic regression model Y = 158.4 − 0.051X − 0.014X2 which describes the relationship between Y sediment loss and X percent cover (0 to 100) was highly significant R2 = 0.81. The effect of the straw was to 1) reduce splash, 2) reduce soil crust formation, 3) block sediment movement, 4) delay runoff initiation, and 5) reduce total runoff loss. A cover coefficient (CC) can be calculated as a ratio of soil loss under any straw cover percent to soil loss under no straw cover. The relationship needs to be tested for other cover types before it is used with cover types different than straw mulch, or substituted for the C factor of the Wischmeier equation.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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