江西省农田灰水足迹时空分析

Temporal and spatial analysis of grey water footprint in Jiangxi Province farmland

为更好地分析江西省农田氮磷污染时间变化趋势和空间分布特征,本文基于《江西统计年鉴》和各地方统计年鉴的相关数据,运用地理信息系统(ArcGIS)和《全国农田面源污染排放系数手册》测算出不同地区氮磷污染流失系数,结合灰水足迹核算方法,对江西省及各县区2000—2020年的灰水足迹及其强度进行计算分析。结果表明:在过去21 a间,江西省农田氮磷灰水足迹总体呈先增后降的变化趋势,氮肥和磷肥灰水足迹峰值分别出现在2011年和2015年;折算后磷肥灰水足迹大于折算后氮肥灰水足迹,因而磷是江西省农田生产的主要污染物,年化肥施用量中占比最大的复合肥是主要污染源;农田氮磷污染物灰水足迹及强度空间分布相似,均呈现中部高、四周低的分布特点,境内农田面源污染严重区域主要为南昌市、宜春市东部地区、铅山县、南丰县和永修县。

To better analyze the temporal trend and spatial distribution characteristics of nitrogen and phosphorus pollution in Jiangxi Province farmland, this article is based on the Statistical yearbook of Jiangxi Province and relevant data from various local statistical yearbooks, using the geographic information system(ArcGIS)and National agricultural non-point source pollution emission coefficient handbook that calculates the loss coefficients of nitrogen and phosphorus pollution in different regions, combined with the grey water footprint calculation method, to calculate and analyze the grey water footprint and its intensity in Jiangxi Province and its counties from2000 to 2020. The results demonstrate that during the past 21 years, the overall nitrogen and phosphorus fertilizer grey water footprint of the farmland in Jiangxi Province first increased and then decreased. The peaks of the nitrogen and phosphorus fertilizer grey water footprints appeared in 2011 and 2015, respectively, and the converted phosphorous grey water footprint is larger than the converted nitrogen fertilizer grey water footprint, so phosphorus is the primary farmland production pollutant in Jiangxi Province. The compound fertilizer, which accounts for the largest proportion of the annual chemical fertilizer application, is the primary source of pollution;the grey water footprint and intensity spatial distribution of the farmland nitrogen and phosphorus pollutants are similar, both presenting the distribution characteristics of high in the middle and low on the surroundings, the key areas with serious non-point source pollution of farmland in the territory are:Nanchang City, the eastern part of Yichun City, Qianshan County, Nanfeng County, and Yongxiu County.