太湖流域农业污染压力分析

太湖及其流域的水环境质量呈现严重恶化趋势,农业污染物的排放是太湖流域水体环境恶化的主要原因之一。太湖流域农业污染物主要来源于种植业、畜禽养殖业和水产养殖业的生产过程。本文从综合考虑种植业、畜禽养殖业和水产养殖业生产过程中产生的污染物对水环境影响的角度,构建农业污染压力模型,计算农业污染压力指数,定量分析了处于太湖流域的江苏省常州和宜兴两市农业污染物排放对水环境影响的严重性。研究结果表明:两市农业生产过程中产生的氮和磷污染物是造成水体污染的主要贡献者,其污染压力指数普遍大于1;农业污染压力指数在空间分布上存在明显差异;虽两市近年来单位面积化肥农药的使用量有所减少,但仍远远高于安全使用量的上限,以常州市为例,2008年单位耕地面积化肥施用量为452.71 kg.hm 2,为2000—2008年期间最少的一年,但仍然高于发达国家为防止化肥对水体污染所规定的平均化肥施用量的安全上限225 kg.hm 2。本文从整体上分析了农业污染物排放对水环境产生的影响,对实现水资源的可持续利用和水环境管理具有一定的参考价值。

Agricultural pollution pressure in the Taihu Lake Basin

The serious water environment quality deterioration in the Taihu Lake Basin(TLB) has been largely blamed on agricultural pollution.The pollutants were mainly from the processing of plant,livestock and poultry and aquacultural products.This paper developed an agricultural pollution model that calculates the pressure index of agricultural pollution based on the cultivation of plants and the breeding of livestock,poultry and aquaculture.The results showed that nitrogen and phosphorus pollutants largely contributed to water pollution with pollution pressure index value greater than one.Spatial distributions of agricultural pollution pressure index differed not only with different cultivation and breeding practices,but also with region.Although fertilizer and pesticide dose per unit area decreased,it was still far above the upper limit of safety usage.For example,the lowest fertilizer dose in Changzhou City during 2000-2008 was 452.71 kg·hm 2(in 2008),which was still above the 225 kg·hm 2 upper safe limit.The findings in this paper served as important reference for sustainable usage of water resources and water environment management in terms of the influence of agriculture pollution on the water environment.