东北黑土区农业非点源磷污染最佳管理措施空间优化配置研究

Northeastern black soil area is one of important regions for crop production and commodity grains in China, which takes the key role in stabilizing national grain markets and keeping national food security. The long term cultivation has caused serious agricultural nonpoint source pollution and threatened water environment safety in this area. Best management practices (BMPs) have been shown to be effective in reducing the nutrient and sediment inputs to receiving water bodies. However, selection of BMPs for placement in a watershed requires optimization of the available resources to obtain maximum possible pollution reduction. At present, nonpoint source pollution process model is commonly applied to geographical allocation of BMPs on a single spatial scale, and the evaluation indicators are usually mitigation efficiency of pollution load. Moreover, the effect of agricultural BMPs implementation on stream water quality is seldom taken into account. The plan of BMPs allocation is difficult to perform for landowners and environmental agency. Given the weaknesses mentioned above, we take the upper watershed of Shitoukoumen reservoir - the drinking water source of Changchun- as our study area and total phosphorus (TP) as the target pollutant. A simple and easy integrated approach will be established for the purpose of identifying the distribution pattern of phosphorus loading at two spatial scales (watershed and filed) so that different allocation plans of BMPs can be designed. More effective performance benefit index will be generated through identifying relationship between the ratio of TP loading mitigation and the probability of detecting a statistically TP improvement. By comparing the thresholds of logistic curve of cost-benefit, the best allocation plan will be determined. The expected results will be very useful for agricultural nonpoint source pollution control and drinking water source protection in Northeastern black soil area.

东北黑土区作为我国重要商品粮基地，区域水环境面临来自农业活动非点源污染的压力日益加大，如何通过优化配置最佳管理措施（BMPs）实现水污染控制目标已成为亟待解决的问题。目前国内外主要利用非点源污染机理模型在单一空间尺度进行BMPs空间配置研究，评价指标多为污染负荷削减量，对方案的可操作性及实施后水质的实际改善程度考虑较少。本项目选取长春市饮用水源地石头口门水库上游流域为研究对象，以总磷为目标污染物，建立一套易于操作的综合评估方法以此识别子流域及地块尺度磷污染负荷分布特征，为BMPs配置方案的构建提供依据；通过辨析BMPs实施后流域磷污染负荷削减比例与总磷浓度显著改善概率间的响应关系，生成更有针对性的效益评价指标；在比较不同BMPs空间配置方案的成本效益logistic曲线突变阈值基础上，筛选最佳方案。研究成果对有效控制东北黑土区农业非点源污染，保护饮用水源地安全，具有重要的理论和实际意义。

东北黑土区作为我国重要商品粮基地，区域水环境面临来自农业活动非点源污染的压力日益加大，如何通过优化配置最佳管理措施（BMPs）实现水污染控制目标已成为亟待解决的问题。本项目选取长春市饮用水源地石头口门水库上游流域为研究对象，以总磷为目标污染物，以子流域及地块尺度磷污染负荷分布特征构建BMPs配置方案；最终通过比较不同BMPs空间配置方案的成本效益logistic曲线突变阈值基础上，筛选最佳方案。.通过本项目研究，主要得到以下结论: 1）苜蓿草带去除径流效率平均可以到达45.02%，对泥沙去除可以达到75.12%，对营养元素流失去除率为60.56%左右；2）垄向区田措施可削减坡耕地径流量68.01%，泥沙量97.23%，TP 93.47%，粮食产量增长25.67%；3）石头口门流域面源磷污染物的产生和输出多集中6-9月。汛期是土壤侵蚀和氮、磷非点源污染防治的关键时期。双阳河、饮马河和岔路河下游为磷发生流失的关键区域；4）四种配置方案的成本效益曲线对比发现，目标聚集为最优方式。从BMPs地块削减效率、不同尺度的磷负荷空间分布规律及水质采样点数量三个角度进行敏感性分析证明该方案是稳定可靠的。研究成果对有效控制东北黑土区农业非点源污染，保护饮用水源地安全，具有重要理论和实际意义。

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