三峡库区中部区域小流域氮磷排放特征及其措施阻控效果的定量评价

Prevention and control measures conducted in small watershed can be the most effective way to govern agricultural non-point source pollution in Three Gorges Reservoir Region. A typical small watershed named Wang-jia-gou in middle Three Gorges Reservoir Region was took as the research object in this project. With the combination of artificial sampling monitoring under natural rainfall and sub basin export automatic monitoring, the dynamic emission process and characteristic of nitrogen & phosphorus pollutants was studied respectively driven by natural rainfall. Besides, the relationship between different prevention and control measures or their combination and nitrogen & phosphorus concentration was analyzed on all of the monitoring points. Quantitative evaluation of the impedance control measures aimed at non-point source pollution in small watershed can be conducted based on the result above. With the application of 4DAgro Farmland Nutrient Migration Model, the control process under different prevention and control measures or their combination can be simulated. Moreover, by inputting monitoring data and analysis result into the simulation system, calibrating the relevant parameter, the mechanism of controlling non-point source pollution under different prevention and control measures or their combination can be revealed, which can provide the basis for the optimal configuration of impedance control measures on agricultural non-point source pollution in small watershed.

以小流域为单元进行农业面源污染防控是三峡库区农业面源污染治理最有效的技术途径。本项目以三峡库区中部典型小流域-王家沟小流域为研究对象，采用小流域天然次降雨人工取样监测与子流域出口自动监测相结合的试验观测方法，研究自然降雨驱动下小流域氮磷污染物排放的动态过程以及小流域层面的氮磷排放特征，分析不同防控措施及其组合与监测点氮磷浓度之间的关系，进行小流域农业面源污染防控措施污染阻控效果的定量评价，应用4DAgro农田营养迁移模型模拟不同防控措施及其组合控制农业面源污染的过程，将监测点的观测和分析结果输入模拟系统，校正相关参数，揭示不同防控措施及其组合控制农业面源污染的机理，为小流域农业面源污染防控措施的优化配置提供依据。

以小流域为单元进行农业面源污染防控是三峡库区农业面源污染治理最有效的技术途径。本项目以三峡库区中部典型小流域-王家沟小流域为研究对象，采用小流域天然次降雨人工取样监测与子流域出口自动监测相结合的试验观测方法，研究了自然降雨驱动下小流域氮磷污染物排放的动态过程以及小流域层面的氮磷排放特征，分析了不同防控措施及其组合与监测点氮磷浓度之间的关系，并对小流域农业面源污染防控措施污染阻控效果进行了定量评价，同时，还应用4DAgro农田营养迁移模型模拟了不同防控措施及其组合控制农业面源污染的过程。研究表明，三峡库区中部小流域（王家沟小流域）地表氮磷排放春季作物时期空间差异最大，秋季作物时期差异最小，主要受到降雨强度、施肥、作物类型及其种植面积等因素影响。同时，优化水田布局与桑树植物篱配置，无论是从土地利用还是从景观优化的角度，均能实现对农业面源污染物的有效拦截。研究结果可为三峡库区小流域农业面源污染防控措施的优化配置提供依据。