洱海流域农业面源污染与水环境变化的关联分析

随着点源污染得到有效控制与治理，农业面源污染已成为湖泊水环境污染的主要来源.该文利用等标污染负荷法和相关统计、调查数据，计算了2006年～2014年洱海流域农业面源污染负荷，在此基础上，运用灰色关联分析方法，测度了农业面源污染与洱海水环境变化的关联性.研究揭示：1) 2014年流域农业污染的总排放量为8 303.63 t，折算成等标排放量COD、TN和TP分别为325.85、1371.29和420.10 m3/a，表明TN为污染超标的主要影响因子；2) 畜禽养殖关联度为0.71，种植业关联度为0.63，表明农业发展整体对洱海水环境影响较大，其中，大蒜、水稻、牛、猪的关联度分别为0.70、0.69、0.74、0.74，贡献率分别为9.35%、10.90%、35.09%、13.19%；3) 从空间分布看，海北片区的三营镇、右所镇、茈碧湖镇为流域重点污染源区，且流域主要污染物的增减变化具有一定的空间非均衡性.据此，探讨了未来洱海流域基于水环境保护的农业发展策略.

Correlation analysis of agricultural non-point source pollution and water environment change in Erhai Lake watershed

Along with the effective control of point source pollution， agricultural non-point source pollution has become the main pollution source of lake water environment. Based on the equivalent standard pollution load method and the relevant survey data， this paper calculates discharges of agricultural non-point source pollution in the Erhai Lake watershed during 2006～2014， and then， using the grey correlation analysis method， correlations are studied between agricultural non-point source pollution and water environment in the Erhai Lake watershed. The research results show that firstly， the total discharges of agricultural non-point source pollution are 8303.63 t， amount to equivalent standard discharges of COD， TN and TP as 325.85， 1371.29， and 420.10 m3/a， respectively， which indicates that TN is the main influence factor for pollution； secondly， the correlation between livestock and water environment is 0.71， and the correlation between crop farming and water environment is 0.63， which show that the influence of agricultural development is relatively significant for water environment. In detail， the correlations of garlic， rice， cattle and pig are 0.70， 0.69， 0.74， 0.69， and the contribution rates are 10.90%， 9.35%， 35.09%， and 13.19%， respectively； thirdly， from the perspective of spatial distribution， the north area are key pollution source areas， such as Sanying town， Yousuo town， ZiBi lake town， besides， the variance of non-point source pollution was non-balanced. According to the above data， the future agricultural development of Erhai Lake watershed is discussed in view of water environment protection strategy.