[Identification of the prior regions for agricultural and rural pollution control in Changshu].

The characteristics such as wide area, dispersion and randomness of agricultural and rural pollution make it difficult to seize the key to pollution control in rural areas. On the scale of township, using inventory analysis, accounting for emissions and emission intensity of the chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) in Changshu, Jiangsu Province, which exists in a total of 4 classes and 6 kinds of agricultural and rural sources such as farmland cultivation (chemical fertilizer application and crop straw abandoned), animal breeding, aquaculture, rural life (domestic sewage and human waste, solid waste), using cluster analysis, identify the prior regions and the prior pollution sources for agricultural and rural pollution control by the sensitivity evaluation, and make agricultural and rural pollution control and management measures more focused. It shows that: in 2007, COD, TN and TP emissions of agricultural and rural pollution sources were 5496.07, 4161.03, and 647.54 t x a(-1), and the emission intensity of COD, TN and TP was 48.84, 36.98, and 5.75 kg x hm(-2). The main pollution source of COD was rural life and aquaculture, and the contribution rate was more than 75%; the main pollution source of TN and TP was agricultural cultivation and aquaculture, and the contribution rate was more than 80%. The sensitivity evaluation identified that the town of Guli and Shajiabang were the prior regions for agricultural and rural pollution control in Changshu; farmland cultivation and aquaculture were the prior pollution sources in the two areas.