Author(s): Wanli Shi; Qinke Yang; Xuezhong Yu; Guanghui Zhang
Linked Author(s):
Keywords: WEPP model; CLIGEN; Sediment yield; Soil loss; The Loess Plateau
Abstract: There is a growing volume of research outputs concerning the application of the Universal Soil Loss Equation (USLE) on different scales in China. However, WEPP model originated from U. S. is seldom conducted in China, especially in the Loess Plateau. To get a wider application to other countries in the world, the study was carried out to evaluate the WEPP model in the loess environment in terms of typical climate, soil, slope and crop management. The climatological data, observed in Ansai experimental station (1986-2003), were used to generate the climate file by CLImate GENerator (CLIGEN). WEPP model was calibrated and validated for the study area with observed runoff and soil loss of 4 years（2001-2004）from 10 runoff plots. The measured surface runoff and sediment yield from plot No. 1 to 4 were employed to calibrate soil erodibility parameters of the WEPP model. In the calibration process, a sensitivity analysis of the WEPP is conducted to optimize model parameterization. Calibrated critical shear stress was 4. 6 pa, interrill and rill erodibility were 2. 8×106kg s m-4 and 0. 321 s m-1, respectively. With the calibrated parameters, runoff and soil loss predicted by WEPP model are lower than the measured values. The relative errors between the simulated runoff and measured data are 50% for cropland and 6. 3% for fallow, while both of them for soil loss are almost 40% . The sensitivity analysis and the calibration process illustrated that WEPP model was sensitive to the effective hydraulic conductivity and the erodibility parameters. Therefore, it is necessary to explore new tillage managements for the reduction of soil loss in the Loess Plateau.
Year: 2013