洞庭湖平原化肥面源污染生态环境风险及脱钩效应

Eco-environmental Risks and Decoupling Effects of Fertilizer Non-Point Source Pollution in Dongting Lake Plain

[目的]推动实现农业经济增长与化肥面源污染生态环境风险的脱钩,为有效治理耕地面源污染和耕地可持续利用提供理论支持。[方法]基于生态环境风险评价模型,从县域尺度评价洞庭湖平原各地区化肥面源污染生态环境风险程度,采用非参数核密度估计洞庭湖平原化肥面源污染生态环境风险区域差异,进而采用脱钩模型进一步分析了洞庭湖平原农业经济增长与耕地化肥面源污染生态环境风险的脱钩关系。[结果](1)2009—2019年洞庭湖平原化肥面源污染生态环境风险指数呈现先升后降的趋势,化肥面源污染生态环境风险指数先由2009年的0.749升至2014年的0.762,然后降至2019年的0.732,经历了由中度风险转为高度风险,后又降为中度风险的过程;中部地区污染更严重;(2)化肥面源污染生态环境风险区域差异明显,呈现两极分散化集聚特征,内部差距先扩大后缩小;(3)洞庭湖平原农业经济增长与化肥面源污染生态环境风险的脱钩关系呈现出明显的阶段性特征:第一阶段为波动期(2009—2013年),第二阶段为强脱钩期(2014—2019年)。[结论]在面源污染治理工作的推进下,洞庭湖平原化肥面源污染生态环境风险经历了先上升后下降的变化趋势,且呈现出明显的区域分异,基本实现与农业经济增长的稳定脱钩,整体呈现出绿色可持续发展趋势。

[Objective]The decoupling of agricultural economic growth from the eco-environmental risk of fertilizer non-point source pollution was promoted,so as to provide theoretical support for the effective control of the non-point source pollution of cultivated land and the sustainable use of cultivated land.[Methods]Based on the eco-environmental risk assessment model,the eco-environmental risk of fertilizer non-point source pollution in each area of the Dongting Lake Plain was evaluated at the county level,and the regional difference of the eco-environmental risk of fertilizer non-point source pollution in Dongting Lake Plain was estimated by non-parameter kernel density,and then the decoupling model was used to further analyze the decoupling relationship between agricultural economic growth in the Dongting Lake Plain and the eco-environmental risk of fertilizer non-point source pollution on cultivated land.[Results](1)From 2009 to 2019,the eco-environmental risk index of fertilizer non-point source pollution in the Dongting Lake Plain showed a trend of rising first and then falling.The eco-environmental risk index of fertilizer non-point source pollution first rose from 0.749 in 2009 to 0.762 in 2014,and then decreased to 0.732 in 2019,first from moderate risk to high risk,and then to moderate risk.Pollution in the central region was more serious.(2)The regional differences in the ecological environment risk of fertilizer non-point source pollution were obvious,showing the characteristics of decentralized agglomeration of two poles,and the internal gap was first expanded and then narrowed.(3)The decoupling relationship between agricultural economic growth and the eco-environmental risk of fertilizer non-point source pollution in the Dongting Lake Plain showed obvious stage characteristics:the first stage was the fluctuation period(2009—2013),and the second stage was the strong decoupling period(2014—2019).[Conclusion]With the promotion of cultivated land source pollution control,the eco-environmental risks of fertilizer non-point source pollution in Dongting Lake Plain had experienced a trend of first rising and then falling,showing obvious regional differences,and the stable decoupling from agricultural economic growth had been basically achieved,and the overall trend of green and sustainable development had been presented.