我国农田面源污染时空演变特征分析

为探究20世纪90年代以来我国农田面源污染风险区域差异及演变特征，运用ArcGIS空间分析技术，分析了我国九大农业区和各省域的地均化肥、农药和农用塑料膜污染空间分布及其长时间演变特征。结果表明1991—2018年我国化肥、农药、农用塑料膜使用量整体呈逐年上升趋势，其面源污染程度逐年加重，农田面源污染的问题更加突出。化肥地均使用量增长101.5%，污染等级从较低等级升高为较高等级。农药地均使用量增长97.6%，污染等级从较低等级升高为较高等级；农用塑料膜地均使用量增长238.2%，污染等级从低等级向较高等级转变。九大农业区化肥、农药和农用塑料膜污染程度整体呈现由早期的较低污染等级升高为目前的较高污染等级。华南区、黄淮海平原区和黄土高原区化肥面源污染加剧程度最突出，黄淮海平原区、长江中下游地区和华南区的农药面源污染加剧程度最突出，而北方干旱半干旱区、华南区和黄淮海平原区农用塑料膜面源污染加剧程度最突出。综上，各省域化肥、农药、农用塑料膜污染呈现不同程度的加重趋势，其中化肥面源污染河南、海南、湖北、广西、陕西和新疆等省加剧严重，农药面源污染湖南、江西、福建、广东和海南加剧最明显，农用塑料膜面源污染上海、新疆、福建、海南、甘肃、山东和浙江加剧比较明显。

Analysis on the spatiotemporal evolution characteristics of agricultural non-point source pollution in China

In recent years, with the continuous improvement of agricultural development, excessive use of chemical fertilizers, pesticides, and agricultural plastic films have become the main reasons that cause agricultural non-point source pollution in China. To explore the regional differences and evolution characteristics of agricultural non-point source pollution risk since the 1990s in China. ArcGIS spatial analysis technology was employed in this study to analyze the spatial distribution and long-term evolution characteristics of fertilizers, pesticides, and agricultural plastic film pollution in nine major agricultural regions and provinces in China. The results show that the overall use of chemical fertilizers, pesticides, and agricultural plastic films is increasing year by year in China from 1991 to 2018, and the grade of non-point source pollution is increasing, and the problem of non-point source pollution is more prominent in farmland. The usage amount of chemical fertilizers on land increased by 101. 5%, and the overall pollution level increased from a lower pollution level to a higher pollution level. The usage amount of pesticides on land increased by 97. 6%, and the overall pollution level changed from a lower level to a higher level; the usage amount of agricultural plastic film on land increased by 238. 2%, and its pollution level changed from a low level to a higher level. The pollution levels of chemical fertilizers, pesticides and agricultural plastic films have changed from the lower pollution levels in the early period to the current higher pollution levels in the nine agricultural areas. The degree of increase of non-point source pollution of chemical fertilizers is the most prominent in Southern China, Huang-Huai-Hai Plain and Loess Plateau. The increase of non-point source pollution of pesticides is the most prominent in Huang-Huai-Hai Plain, Middle-lower Yangtze Plain and Southern China, the pollution level of agricultural plastic films non-point source pollution has increased most prominently in Northern arid and semiarid region, Southern China and Huang-Huai-Hai Plain. The pollution degree of chemical fertilizers, pesticides, and agricultural plastic films in various provinces showed different degrees of increasing trends. In conclusion, the non-point source pollution of chemical fertilizers became more serious in Henan, Hainan, Hubei, Guangxi, Shaanxi and Xinjiang, the non-point source pollution increase of pesticides in Hunan, Jiangxi, Fujian, Guangdong and Hainan is the most obvious, and the agricultural plastic film non-point source pollution has increased significantly in Shanghai, Xinjiang, Fujian, Hainan, Gansu, Shandong and Zhejiang.