中文摘要：

运用SWAT模型对水土保持、减少化肥农药施用量、减少表层土壤施肥量比例、退耕还林及综合措施对于不同非点源污染在灞河流域的消减效果进行了模拟。结果表明：（1）水保措施对N、P、DDT的削减效果最高可达44.4%,相对而言对于溶解磷的削减效果不是很明显。（2）减少施肥量措施对溶解P、总P、NO3-N的削减率相对较高,而对于其它指标的削减效果不是很明显;减少农药施用量措施对DDT的削减效果较好,削减率可达50.92%。（3）减少表层土壤施肥量占总施肥量的比例措施对溶解P、总P的削减效果较为明显,而对于其它指标的削减效果不是很明显。（4）退耕还林措施对于各项指标都有着明显的削减作用。（5）综合措施对于各项指标均有着很好的削减作用,总体看来综合措施可大大减少流域内的非点源污染负荷,对于改善流域水环境质量可起到巨大的作用。研究为灞河流域非点源污染最佳管理措施的实施提供了明确实际的决策支持。

英文摘要：

At present,China is in the midst of a gradual transition period of water pollutant composition. The contribution rate of point source pollution is gradually declining,but the contribution rate of agricultural non-point source pollution is gradually increasing. In this paper,the SWAT model was used for simulating the abatement effects of different non-point source pollution control measures such as soil and water conservation,reducing fertilizer and pesticide use amount,reducing the ratio of surface soil fertilizer use,returning farmland to forest and the comprehensive measures in the Bahe Basin, Shaanxi Province, China. Of the basic information database for the SWAT model mainly includes spatial database,meteorological data and management measures,etc.Spatial database mainly includes digital elevation model（DEM）,land use map,soil type map,meteorological data,including daily average rainfall,the highest and lowest temperature,solar radiation,wind speed and relative humidity,etc.,management measures mainly include crop planting and fertilizing,farming,etc. This study is based on the model in simulation process of calibration and verification. Model calibration and verification results is good,which can be used for simulating non-point source pollution in Bahe watershed. Results show as follows：（1）the abatement effect of the soil and conservation measures to nitrogen,phosphorus and DDT is as high as 44.4%,and relatively the effect to dissolved phosphorus is not very obvious.（2）the effect of reducing fertilizer use amount to dissolved phosphorus,total phosphorus,nitrate nitrogen reduction rate is relatively high,while for other indicators of the effect is not obvious;the abatement effect of reducing pesticide use amount to DDT is good,and the abatement rate can reach 50.92%.（3）the measures of reducing the proportion of the surface soil fertilizer use in the total fertilizer use amount have more obvious effects for the reduction of dissolved phosphorus,total phosphorus,and for other indicators of the