Study On The Relationship Between Nitrogen Nutrient Salt Pollution And Watershed Economic Growth In Ganjiang River Based On VAR Model

Ganjiang River basin,located in the middle and lower reaches of the Yangtze River,is the largest freshwater lake in China,Poyang Lake.In recent years,with the development of social economy,the water quality of Ganjiang River is getting worse and worse,which makes Poyang Lake face the threat of eutrophication.There have been a lot of researches on Poyang Lake and Ganjiang River.It mainly focuses on the characteristics of water quality changes in the Ganjiang River,the source of nutrients in the Ganjiang River,or the impression factors of the nutrients in the Ganjiang River.The VAR model can be used to analyze the dynamic relationship between the economy and the economy of Ganjiang River,and the dynamic relationship between the economy of Ganjiang River and the nitrogen nutrient load of Ganjiang River can be analyzed effectively and directly by VAR model.Therefore,this study analyzed the current economic situation of Ganjiang River Basin and the changing rule in 2007/2016,calculated the nitrogen nutrition load of Ganjiang River in Poyang Lake from2007 to 2016,combined with the hydrological and water quality data of Ganjiang River,and explored the relationship between the economy and environmental pollution of Ganjiang River Basin by using VAR model.In this study,the concentration changes of TN,NH₄⁺-N and NO₃^--N along the Ganjiang River were analyzed,the present situation of nitrogen nutrition pollution in Ganjiang River was analyzed,and the variation rule of nitrogen nutrients along the Ganjiang River was discussed.The nitrogen nutrition data and water quantity data of Ganjiang and Poyang lakes from 2007 to 2016 were analyzed to reveal the characteristics of nitrogen nutrient loading in Ganjiang and Poyang lakes from 2007 to2016,and to explore the contribution of Ganjiang nitrogen nutrients to Poyang Lake.By analyzing the economic data of Ganjiang River Basin from 2007 to 2016,this paper reveals the changing characteristics of Ganjiang River Basin economy in recent years.On this basis,the VAR model is used to analyze the dynamic relationship between different GDP,output value of Ganjiang River and the load of Ganjiang River nitrogen into lake,and the relationship curve between economy and environment of Ganjiang River basin is analyzed,and the relationship between economy and environmental pollution is revealed.It provides scientific basis for the management of Ganjiang River and Poyang Lake environment and provides reference for the sustainable development of Ganjiang River Basin.Through the above research,the following conclusions are drawn:?1?Characteristics of nitrogen nutrient pollution in Ganjiang RiveThe concentration of nitrogen TN in the Ganjiang River was higher than that in the upper reaches of Ganjiang River.The concentration of TN in the middle and lower reaches of Ganjiang River was higher than that in the upper reaches,and the concentration of TN in low water period was higher than that in high water The main source of TN in Ganjiang River is urban sewage and mining industry wastewater.The influence of mining industrial wastewater on the concentration of TN is greater than that of urban domestic wastewater.Controlling the discharge of wastewater from mining industry is beneficial to the decrease of TN content in Ganjiang water body.In addition,the Wanan Reservoir and the Xijiang River Water Conservancy Project have a retention effect on the nitrogen nutrients of the Ganjiang River,and a positive effect on the conversion of NH4-N to NO^3--N.The greater the water volume,the stronger the self-purification ability of the Ganjiang River water body.?2?Characteristics of nitrogen nutrient loading in Ganjiang River from 2007 to2016From 2007 to 2016,the discharge of Ganjiang River was similar to that of Poyang Lake,but the inter-annual variation was not obvious.In terms of month,the volume of water in April-June was larger than that in October-February.The variation regularity of nitrogen nutrition load in Ganjiang River and Poyang Lake is similar,the inter-annual variation characteristic is gradually increasing,the monthly variation characteristic is small in high water season and large dry period,the contribution of Ganjiang River to Poyang Lake water quantity is 44.24%,the load contribution is56.64%.Ganjiang River is the main contributor to nitrogen nutrition and water quantity in Poyang Lake.?3?Economic characteristics of Ganjiang River BasinThe main driving force of the current economic development in the Ganjiang River Basin is the secondary industry,followed by the tertiary industry and the primary industry.The role of the tertiary industry in promoting GDP is gradually rising.Ganjiang River Basin continued to grow from 2007 to 2016,but the growth rate of the second output value and the third output value was much higher than that of the second output value.?4?0Relationship between economy and nitrogen nutrient loading into Lake in Ganjiang River BasinThe relationship between GDP of Ganjiang River basin and the load of Ganjiang River nitrogen entering lake is"inverted U".The increase of GDP in Ganjiang River basin can promote the load of Ganjiang River nitrogen entering lake,and the load of Ganjiang nitrogen entering lake can restrain the load of Ganjiang River basin.Different output value of Ganjiang River basin has obvious promoting effect on the load of Ganjiang River nitrogen into lake.Agriculture is the main influencing factor of nitrogen entering lake load of Ganjiang River in the early stage,and industry is the main influencing factor in the middle and later stages of Ganjiang River.The inhibitory effect of Ganjiang River nitrogen loading on the different output value of Ganjiang River basin is the third output value>the second output value>the first output value.