Submitted to: American Society of Agri Engineers Special Meetings and Conferences Papers
Publication Type: Abstract Only
Publication Acceptance Date: 7/17/1996
Publication Date: N/A
Technical Abstract: The objective of this study was to compare runoff and soil loss predictions from the WEPP Hillslope model (version 95.1) to measured losses for eight cropping and management treatments where runoff and soil losses had been measured over an 11-year period (1983 through 1993) from natural rainfall erosion plots located near Columbia, MO. The eight treatments were continuous cultivated fall (FAL), continuous corn conventionally tilled (CCCT), continuous corn chisel plowed (CCCP), continuous corn in no-till (CCNT), continuous soybean conventionally tilled (BBCT), continuous soybean chisel plowed (BBCP), continuous soybean in no-till (BBNT), and continuous no-till alfalfa (ALFA). The mean annual predicted runoff averaged over the eight treatments was 224 mm compared to the measured value of 198 mm. On an individual treatment basis, WEPP overpredicted mean annual runoff from all treatments except CCNT and BBNT. All mean annual predictions were within 15% of the measured values, except for ALFA and BBCP. For the high runoff years of 1985, 1990, and 1993, WEPP runoff predictions were generally within 20% of the measured values. The mean annual predicted soil loss averaged over the eight treatments was 1.33 kg/m**2 compared to the measured value of 1.28 kg/m**2. On an individual treatment basis, WEPP overpredicted soil loss for two of the eight treatments - BBCT and BBCP. All mean annual predictions were generally within 50% of the measured values. Annual predictions of runoff and soil losses were generally higher than those measured for low runoff and soil loss years. Results from this validation study can be compared to other studies to obtain an overall evaluation of WEPP performance for different climate, soil, and cropping regions across the U.S.