基于AnnAGNPS模型的黄土高原小流域土壤侵蚀定量评价

以位于黄土丘陵沟壑区的砖窑沟流域为试点，利用AnnAGNPS模型进行土壤侵蚀定量评价。采用流域8次径流事件监测数据进行模型检验，径流量和沉积物量的相对误差分别为10%和-10%，AnnAGNPS模型能够比较理想地模拟流域长期的径流量和沉积物量，并可应用于黄土丘陵沟壑区的径流流失和土壤侵蚀定量评价。采用2004年土地利用状况模拟分析了流域土壤侵蚀量及其空间分布，结果表明：该流域平均片蚀和细沟侵蚀强度为3508 t/(km²·a)，属中度侵蚀等级，黄土沟壑地的平均侵蚀强度最大，属极强度侵蚀等级；严重的沟道侵蚀显著增加了运移到流域出口的泥沙。

Soil erosion quantitative evaluation of small watershed in Loess Plateau based on AnnAGNPS model

The Annualized Agricultural Non-Point Source Pollution model(AnnAGNPS) was used to evaluate soil erosion of Zhuanyaogou watershed in the hilly area of loess Plateau in China. Results show that the relative errors of runoff and sediment yield are 10% and -10% using monitoring data of eight times runoff events, respectively. AnnAGNPS model provides reasonable estimation result of long-term annual runoff and sediment yield. AnnAGNPS model is suitable for quantitative evaluating runoff losses and soil erosion in the hilly area of Loess Plateau. Therefore, the soil erosion of small watershed was simulated based on the land use pattern in 2004 and the spatial distribution of soil erosion were analyzed. The average sheet and rill erosion intensity is 3508 t/(km²·a), which belongs to moderate erosion. Average gully erosion intensity belongs to intensive erosion, which is distinctly higher than that of other land use types. Because there is serious gully erosion, the sediment loading of watershed outlet is obviously added.