Study On Pollution Assessment Of Typical Livestock And Poultry Intensive Area In Tieling

Since the reform and opening up,China's national strength has been increasing,people's living standards have been improving,the demand for livestock and poultry has been increasing,which has led to the increasingly serious problem of livestock and poultry pollution,which has become a hot issue of concern.Liangzi River Basin in Tieling City is a typical livestock and poultry intensive area in Liaoning Province.For many years,the water quality of Liangzi River Basin has declined due to the direct discharge of livestock and poultry breeding pollutants into the river,and the pollution of COD and ammonia nitrogen in the basin is serious,which has had a serious impact on the water quality of Liaohe River.Therefore,it is urgent to carry out evaluation and Research on the pollution of livestock and poultry.In this paper,the situation of livestock and poultry breeding in 8 towns and 125 villages in Liangzi River Basin was investigated,and the pollution characteristics were analyzed.The evaluation of livestock and poultry breeding capacity in the intensive area was carried out from three aspects of livestock and poultry manure load,livestock and poultry bearing capacity early warning value,and livestock and poultry breeding maximum bearing capacity.On this basis,the "source strength,way,receptor" of livestock and poultry breeding pollution was analyzed ”Three aspects of the pollution risk assessment system,carried out a typical intensive areas of scattered livestock breeding pollution risk assessment.The main results are as follows:(1)according to the investigation results of livestock and poultry breeding in the intensive area of livestock and poultry in Liangzi River Basin,the main livestock and poultry breeding in this area is pig and chicken breeding.However,there are significant differences in the cultivation patterns of different towns,of which Quantou town is dominated by geese,Liangzhongqiao town is dominated by cattle,pigs and sheep.At the same time,the number of livestock and poultry in different towns is quite different.The result of converted livestock and poultry pig equivalent shows that Liangzhongqiao has the largest livestock and poultry pig equivalent,which is 151100,while Quantou hasthe least livestock and poultry pig equivalent,which is only 2916000,only one fifth of Liangzhongqiao.(2)the assessment of the bearing capacity of livestock and poultry in the study area is carried out by using nutrient balance method and ArcGIS software.The early warning value of the bearing capacity of livestock and poultry in the study area is obtained by calculating the ratio of the load of livestock and poultry manure and the maximum load of livestock and poultry manure.From the early warning value results,it can be seen that the overall early warning value of the bearing capacity of livestock and poultry in the study area is pollution level 2 There is a certain degree of pollution to the environment,and there is a certain difference in the early warning value of each town.Among them,Tongjiangkou Town,Liangzhongqiao town and old town have two levels of early-warning value pollution;Daxing town has the highest level of early-warning value pollution,which is three levels,so it is necessary to control and coordinate the development of animal husbandry;there is still a certain space for the development of animal husbandry in other towns.At the same time,the maximum carrying capacity of livestock and poultry breeding is calculated.Through the results of the maximum carrying capacity of livestock and poultry breeding in each town,the maximum carrying capacity of livestock and poultry in the study area is 836900.Among them,the livestock and poultry breeding capacity in Daxing Town,Liangzhongqiao town,Laocheng Town,Tongjiangkou town and Changtu town all exceed the maximum carrying capacity of livestock and poultry in each town,and the risk of livestock and poultry pollution is high.(3)The risk assessment of livestock and poultry breeding pollution refers to the multi factor weighted comprehensive scoring method,and 13 relevant indicators are selected from the three aspects of source strength,approach and receptor to establish an indicator system.Combined with ArcGIS software,the risk assessment index of livestock and poultry breeding pollution is calculated,and the risk of livestock and poultry breeding pollution is analyzed.Through the classification of risk assessment,the overall livestock and poultry breeding pollution in the region is studied The risk of contamination is high.Among them,the fourth level area with the highest risk of livestock and poultry pollution covers an area of 1308 hectares,accounting for 24% of the total area of typical areas,mainly distributed in Daxing Town,Tongjiangkou town and old town;the third level area of livestock and poultry pollution risk area is 1756 hectares,accounting for 32% of the total area of typical areas,mainly distributed in Liangzhongqiao town and Changtu town;the second level area of livestock and poultry pollution risk area is 1765 hectares,accounting for 33% of the total area of typical areas,mainly distributed in qingyunbao town and Babao town;the first level area of livestock and poultry pollution risk area is 6020 hectares,accounting for 11% of the total area of typical areas,mainly distributed in Quantou town.Therefore,we should strengthen the monitoring and management of livestock and poultry breeding in the research area,and improve the management of livestock and poultry manure.