农村水环境政策与污染的时空迁移特征及关系

为了揭示农村水污染与政策治理的时空演化关系，在测算政策力度与污染强度的基础上，绘制两指标的重心迁移轨迹，并结合夏普利值分解法确定各省份所属的“政策-污染”类型，进一步采用格兰杰因果检验法深入剖析各类型下政策与污染的因果关系。结果表明：政策与污染的重心均位于我国东南部，但两者的迁移轨迹联动性较差，前者呈现“偏南-偏西-偏北-偏东”的迁移趋势，而后者整体向南迁移；从政策与污染的关系来看，“增长-降低”型省份的污染降低导致政策力度增长，且东、西部省份增长的动因有所不同；“降低-降低”型省份的污染降低会导致政策力度下降，但在具体污染维度上存在政策关注失衡现象；所有“污染增长”型省份在两指标上不存在格兰杰因果关系。建议在未来政策制定中考虑政策与污染结果的联动性，加强政策的精准性、协同性和前瞻性，这将有助于提升政策规制的效率和效果。

Spatiotemporal migration patterns and relationships between rural water environment policies and pollution

In order to reveal the temporal and spatial evolutional relationships between rural water pollution and the corresponding governance policies, the migration paths of gravity centers for the two indicators were plotted based on measurements of policy strength and pollution intensity. Then, various provinces were classified into different “policy-pollution” types by using the Shapley value decomposition method, and the causal relationship between policy and pollution under each type was analyzed based on the Granger causality test method. The results showed that both the gravity centers of policy and pollution located in southeast China, but their migration paths were not aligned with each other. The former exhibited a“south-west-north-east”directional trend, whereas the latter consistently demonstrated a propensity for migration towards the south. In terms of the link between policy and pollution, it was observed that the reduction in pollution intensity contributed to an enhancement in policy strength in“growth-reduced”type provinces. However, the drivers for this enhancement differ between eastern and western provinces. As for provinces classified as“reduced-reduced”, the decrease in policy effectiveness was found to be a result of reduced pollution intensity; however, there were instances of policy deviation evident in specific dimensions of pollution. At last, the provinces falling under the "pollution growth" category did not exhibit Granger causality between policy and pollution. Therefore, it was recommended that future policy-making incorporates its association with pollution outcomes and enhances the precision, synergy, and foresight of policies, which is beneficial to the elevation of efficiency and effectiveness of policy formulation.