湖南省农业面源污染时空特征及其与粮食生产的脱钩效应

揭示粮食生产大省农业面源污染时空变化规律及其与粮食生产内在脱钩关系,为农业生产管理提供理论依据。该文以湖南省为研究区,基于农村统计年鉴等数据并选取化肥、牲畜排泄物和农药污染源为研究对象,采用清单分析法评估2007一2019年农业面源污染时空变化特征,并基于脱钩理论揭示粮食生产与农业面源污染的脱钩效应。结果表明:1)研究期内,湖南省农业面源污染物的排放强度持续降低,其中牲畜污染排放强度下降幅度达到35.16%,由2007年的60.21kg/hm^(2)降至2019年的38.04kg/hm^(2),化肥污染排放强度和农药污染排放强度分别下降了6.05%和10.13%,农业面源污染政策管控措施效果明显;2)农药、牲畜污染排放强度呈显著聚集性效应,高排放区主要分布在湘中、湘南及湘东地区,而化肥污染高值区逐渐向湘东地区聚集;3)湖南省农业面源污染治理效果显著,粮食生产与3类污染物排放强度均呈阶段性耦合脱钩特点。最后,本文提出了优化畜禽养殖结构,在保障粮食生产前提下控制化肥施用数量,推广农药减量和虫害防治技术等政策建议。

Spatio-temporal characteristics of agricultural non-point source pollution and its decoupling relationship with grain production in Hunan Province

Based on a data from 2007 to 2019 rural statistical yearbooks and other sources about fertilizers, livestock excrement, and pesticide pollutions of Hunan Province, and applying the inventory analysis method and the decoupling theory, this study seeks to uncover the spatiotemporal variation patterns of agricultural non-point source pollution in Hunan Province, to examine its intrinsic decoupling relationship with grain production, and to provide a theoretical basis for managing agricultural production. Results reveal that: 1) Throughout the study period, the intensity of agricultural non-point source pollutants in Hunan Province demonstrated a consistent downward trend. Among them, the intensity of livestock pollution emissions decreased by 35.16%, from 60.21 kg/hm2 in 2017 to 38.04 kg/hm2 in 2019; the intensity of fertilizer pollution emissions and pesticide pollution emissions decreased by 6.05% and 10.13%, respectively, indicating that the policy control measures for agricultural non-point source pollution were effective; 2) The emission intensity of pesticide and livestock pollution showed a significant aggregation effect, with high emission areas mainly distributed in central, southern, and eastern Hunan, while the high-value area of fertilizer pollution gradually located in eastern Hunan; And 3) the control of agricultural non-point source pollution in Hunan Province was notably effective, with the coupling and decoupling characteristics between grain production and the emission intensity of the three types of pollutants occurring in distinct phases. Lastly, the paper proposes the following policy recommendations, optimizing the structure of livestock and poultry breeding, regulating the amount of fertilizer application while ensuring grain production, and advocating the reduction of pesticide usage and the implementation of effective pest control technology.