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| Applicability of APEX model for slope scale in the Middle and Upland Huaihe River |
| Yin Liming1,2，Pan Jianjun2，Wang Xiuying3 |
| 1． Soil and Water Conservation Office, Department of Water Resources of Hunan Province， 410007, Changsha;2． College of Resource and Environmental Sciences, Nanjing Agricultural University，210095, Nanjing： China;3．Texas AgriLife Research, TX 765029622, Temple, USA |
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Abstract This study was conducted to evaluate the applicability of Agricultural Policy Environmental eXtender (APEX) model using daily runoff and sediment yield (1982—1986) collected from three plots located in the Middle and Upland Huaihe River. Sensitivity analysis was conducted for the surface runoff and soil erosion components using Extended Fourier amplitude sensitivity test. Then the automatic calibration procedure was used for this study, which utilized Monte Carlo simulation and multi-objective function techniques. Moisture condition 2 curve number (CN2), curve number index coefficient (CNIC), conservation practice factor (PEC), and peak rate-rainfall energy adjustment factor (APM) were influential for sediment yield, and that CN2 and CNIC were influential for surface runoff. The absolute value of the percent errors of mean was within 20％, with Nash-Sutcliffe efficiency and R2 values above 0.45 and 0.55 respectively for both daily runoff and sediment yield for the three plots during the calibration period. For the validation period, the APE was within 25%, with the EF and R2values above 0.4 and 0.5 respectively. The results show that APEX model is applicable to slope scale and is a useful tool for assessing soil and water loss for different management practices in the Middle and Upland Huaihe River.
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Received: 28 June 2011
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