对农村面源污染物负荷的估算、来源分析及控制措施制定是当前研究的热点之一。利用输出系数模型和生态系统服务与权衡综合评价模型（ Integrate valuation of ecosystem services and tradeoffs tool， InVEST 模型）估算宝兴县面源污物总氮（ TN）、总磷（ TP）负荷，并结合水环境功能分区标准，分析面源污染物的超标情况。旨在揭示山区农村面源污染治理的空间异质性，为农村面源污染防治规划、山区水环境治理效率的提升提供科学依据。结果表明， 1） 2010 年宝兴县面源污染物 TN、 TP 负荷分别为 1 156.44、 81.41 t/a， TN、 TP 负荷的空间格局整体上呈现出分布不均，局部集中，靠近水体的规律； 2）不同污染源对 TN、 TP 负荷的贡献率大小顺序均为：畜禽养殖>农业用地>农村生活； 3）从流域尺
度看，宝兴县 TN、 TP 负荷没有超过 III 类水质标准规定的污染物负荷阈值；而从 30 m×30 m 栅格尺度看，宝兴县 TN、TP 超标量分别为 763.63、 51.16 t/a，其超标区域主要集中在耕地、草地、居民地以及靠近水体的地方，以上超标区域即为面源污染控制和治理的关键区域。
 

Non-point source (NPS) pollution produced from agricultural production activity is one of the largest threats to water environment. The management and control of NPS pollutants to achieve the goals of improving surface water quality have gotten an increasing concern throughout the world. Because of the heterogeneity of key driving factors in NPS pollutions such as terrain, precipitation, and vegetation type, the management of NPS pollution in mountainous areas needs more meticulous effort than the plain areas. In this research, considering the characteristics of the spatial heterogeneity of the natural and human factors in mountainous areas, the loads of NPS pollutants, such as total nitrogen (TN) and total phosphorus (TP) are evaluated by the export coefficient model and the InVEST (integrate valuation of ecosystem services and tradeoffs tool), which is a water purification model. The excesses of NPS pollutants are analyzed according to the water environmental function zoning. The research is intended to reveal the spatial difference of NPS pollution in mountainous areas, determine the key regions for management, and provides a foundation for regional pollution control planning and environmental management efficiency promotion in mountainous areas. The method to estimate and evaluate NPS pollutants loads is developed based on the export coefficient model and InVEST water purification model, and is successfully applied to the case study of Baoxing County, showing the applicability of this method for mountainous areas. The results indicate that: 1) TN and TP loads in Baoxing County are respectively 1 156.44 and 81.41 t/a in 2010, and the spatial distribution of TN and TP loads has the characteristics of uneven distribution, local concentration, and closing to the water. 2) The contributions to pollution from various types of pollutant sources are different. The magnitude order for the contribution from various types of pollutant sources is livestock and poultry breeding > agricultural land > rural life. As above mentioned, the contribution of the livestock and poultry breeding to NPS pollution is the biggest and sustainable resource management should be prioritized in an effort to reduce the burden. Such management practices may involve building methane tanks, field ponds and the comprehensive utilization of waste facilities, which are aimed to reduce the level of NPS pollutant export into water bodies. 3) Compared with the pollutants thresholds of water quality standard at Class III at the watershed scale, the total amounts of TN and TP loads in Baoxing County do not exceed the thresholds. However, at the 30 m × 30 m grid scale, according to the pollutant load, water yield and water quality standard at Class III, TN and TP excesses in Baoxing County are calculated, and the results are respectively 763.63 and 51.16 t/a. The excesses of NPS pollutants in mountainous areas show significant spatial variation. The regions in which TN and TP loads exceed the thresholds are mainly distributed in cultivated land, grassland, residential land and the regions near the water, and these regions are the key regions for NPS pollution control and management. © 2016, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering.