洞庭湖生态经济区养猪业污染物排放时空格局分析

Spatio-temporal patterns of pollutant loads from the pig husbandry in the Dongting Lake eco-economic zone

养殖污染时空格局研究对于有的放矢地开展污染综合治理与促进养殖业的可持续发展具有重要意义。以洞庭湖生态经济区湖南省部分为研究区域,利用2000-2014年农业统计数据,采用污染排放系数法和空间格局分析技术,系统分析区内养猪业主要污染物化学需氧量(COD)、总氮(TN)、总磷(TP)排放的年际动态及其空间格局,探讨污染负荷形成的原因。结果表明,近15 a来洞庭湖地区养猪规模与污染排放量总体呈现先增后略减然后再持续增加的变化态势,2007年达到最高峰。研究区养猪业存栏规模从2000年的1 469.4万头上升到2014年的2 010.2万头,COD、TN和TP排放量分别由2000年的112.99、11.75与1.10万t/a增加到2014年的154.56、16.07与1.51万t/a。从空间格局来看,养猪污染负荷最大的县(市)主要为洞庭湖西部的常德市区、东南部的汨罗市和望城区,且高污染负荷区呈逐年扩大的态势。洞庭湖生态经济区养猪业的空间格局与当地人口密度、生产习惯、政策及市场导向密切相关。因此,从政策层面推进健康养殖和发展生态循环农业是洞庭湖生态经济区养猪污染防控的关键。

Study on the spatio-temporal pattern is of importance on the comprehensive pollution control and sustainable development for animal husbandry. In this paper, the Dongting Lake eco-economic zone （DLEZ） in Hunan Province was selected as the study area. The inter-annual dynamics and spatial patterns of pollutants （COD, TN and TP） from the pig husbandry were studied. To find out the cause of the pollution, the methods of pollutant discharge coefficient and ArcGIS spatio-temporal analysis were applied. The primary data of the pig population were collected from the local Agricultural Statistics Yearbooks from 2000 to 2014. Results showed that the pig population and pollutant loads generally showed an increase-decrease-increase trend during the last 15 years and peaked in 2007. The pig population increased from 14.7 million in 2000 to 20.1 million in 2014. The total loads of COD, TN, and TP increased from 112.99× 10^4, 11.75× 10^4, and 1.10×10^4 t/a in 2000 to 154.56× 10^4, 16.07× 10^4, and 1.51× 10^4 t/a in 2014, respectively. In terms of spatial pattern, the areas with the highest pollutant loads distributed in Changde in the western DLEZ and Miluo and Wangcheng in the southeastern DLEZ. Furthermore, these areas expanded year by year. The spatial pattern of pig husbandry in the DLEZ was closely related to the local population density, production habit, and policy and market directions. Therefore, promoting the healthy pig husbandry and encouraging ecological cycling agriculture by polices are the key approaches to control the pollution of pig husbandry in the DLEZ in Hunan Province.