Analysis of Agricultural Non-point Source Pollution and Regional Difference in Mianyang City

Agricultural non-point source pollution situation in Mianyang city during 2003-2011 and the difference of agricultural non-point source pollution among nine regions under Mianyang city's respective jurisdiction in 2001 were analyzed,which could provide scientific basis for putting forward appropriate measures to control agricultural non-point source pollution.The results indicated that the pollutions of pesticides,agricultural film and crop straw increased,and rural domestic garbage pollution reduced during 2003-2011.The nutrient pollutants(CODCr,TN and TP)came from livestock and poultry,fertilizer and rural domestic waste,and showed an rising trend in general,nutrient pollutants from livestock and poultry and fertilizer increased,but the nutrient pollutants from rural domestic wast reduced.In 2011,the pollution of pesticide,agricultural film,crop straw and rural domestic waste was the most serious in Fucheng district,followed by Santai county and Jiangyou city;the total equivalent pollution load of nutrient pollutants was the highest in Santai county,and land loads of nutrient pollutants in Fucheng district and Yanting county were higher than the other regions.Land loads coefficient indicated that pollution of CODCr,TN and TP presented obvious regional differences,and posed a serious threat to environment of Jiangyou city,Fucheng district and Yanting county and little threat to environment of Pingwu county.The cluster analysis of all pollutants indicated that Jiangyou city,Youxian district,Fucheng district,Santai county and Yanting county were heavy pollution area,middle pollution area included Beichuan county,Anxian county and Zitong county,Pingwu county was slight pollution area.