Spatial And Temporal Characteristics Of TN,TP And COD Pollution From Agricultural Non-point Source Pollution And Their Control Regionalization In Shandong Province

This paper takes 136 counties(cities and districts)in Shandong Province as the research object,and through the relevant data and parameters of agricultural non-point source pollution in the region,uses inventory analysis,isostandard pollution index method,cluster analysis and environmental Kuznets model(EKC)and other methods.On the basis of calculating the emissions of agricultural non-point source pollution generated by fertilizer application,livestock and poultry breeding and aquaculture in Shandong Province,this paper studies the spatial and temporal differences of agricultural non-point source pollution in Shandong Province,conducts a regionalization study on agricultural non-point source pollution in Shandong Province,and discusses the relationship between agricultural non-point source pollution and agricultural economic development,so as to provide a more comprehensive idea for county control in Shandong Province.It has important theoretical and practical significance for the prevention and control of agricultural non-point source pollution in Shandong Province.The results show that:(1)From the perspective of time scale,the total emission of agricultural non-point source pollution in Shandong Province in 2020 will be 1,332,500 tons.Among them,the emissions of COD,TN and TP were 595,200 t,456,100 t and81,200 t,respectively.The main source of agricultural non-point source pollution in Shandong Province was livestock and poultry breeding.The total emission of isostandard pollution was 4.06 ×1011m3,TN was the most important pollutant of agricultural non-point source pollution in Shandong Province.From 2010 to 2020,the total load of agricultural non-point source pollution decreased from 1,195,900 tons to1,332,500 tons,showing a trend of "increase-decrease-increase-decrease" on the whole.(2)From the perspective of spatial evolution,from 2010 to 2020,the number of COD pollution output in extremely high volume areas decreased from 5 to 3,and the number of high volume areas increased from 34 to 48 and then decreased to 35;From2010 to 2020,the number of TN pollution output in extremely high volume regions increased from 3 to 6,and the number of high volume regions decreased from 35 to22.From 2010 to 2020,the number of TP pollution output increased from 9 to 16 in extremely high volume regions,and the number of high volume regions increased from 18 to 21 and then decreased to 16.From 2010 to 2020,the total amount of agricultural non-point source pollution in the extremely high volume areas decreased from 10 to 8,and the number of high-volume areas increased from 25 to 38 and then decreased to 25.(3)The change trend of agricultural non-point source pollution of fertilizer pollution,livestock and poultry farming pollution and aquaculture pollution with the growth of output value of agriculture,forestry,animal husbandry and fishery in Shandong Province showed a typical "positive N-type" EKC relationship,and the decline turning point was at the values of 0.99 million yuan,11,900 yuan and 0.84 million yuan respectively.At present,the output value of agriculture,forestry and fishery in Shandong Province has not broken through the inflection point,and the pollution of livestock and poultry industry is positively correlated with the output value of agriculture,forestry and fishery,indicating that the growth process of output value of agriculture,forestry and fishery in Shandong Province should also be accompanied by the increase of pollution output of livestock and poultry industry.With the increase of the output value of agriculture,forestry,animal husbandry and fishery,the pollution output of fertilizer and aquaculture decreased,and was in the declining stage of the EKC curve at present.(4)In the control area,it is divided into 3 first-level districts and 42 second-level districts;According to the types of pollution sources,it is divided into six types of pollution,among which,most counties and districts are dominated by livestock and poultry farming pollution,followed by fertilizer-livestock and poultry farming pollution,and comprehensive pollution includes Kenli District and Taierzhuang county,which is the most difficult type to control.