Study On Agricultural Non-point Source Pollution Investigation And Control Strategy In Tiaoxi River Basin

In recent years,with the follow-up and attention to the point source pollution control in the water environment,the issue of non-point source pollution has gradually received attention.Among them,the influence of agricultural non-point source pollution on the quality of water environment has gradually increased,which has become an important direction in the study of water environmental pollution.The Tiaoxi River Basin in the north of Zhejiang Province is an important tributary of the Taihu Basin.The water quality of the Tunxi River Basin is closely related to the water environment quality of the Taihu Lake.In recent years,the agricultural economy of the Tiaoxi River Basin has developed and gradually become a typical river for agricultural non-point source pollution,which seriously threatens the improvement of the water environment in its surrounding basin and the long-term development of water resources in the basin.Based on the characteristics of non-point source pollution in the Tiaoxi River Basin,this study explored the non-point source pollution control and control measures in the Tiaoxi River Basin according to the characteristics of the surface source pollution and the local conditions,and proposed corresponding solutions and countermeasures.Taking the Tiaoxi River Basin as the research object,the nitrogen balance model was used to calculate the nitrogen budget in the Tiaoxi River Basin for a certain year.From the nitrogen budget,the statistical load of agricultural non-point source pollution in the basin was obtained,and then the comprehensive water quality was selected.The index method specifically analyzed the current status of water quality in the basin,determined the source of total nitrogen and total phosphorus pollutants in the basin and the proportion of pollution,and finally derived the causes of each pollution source and the control strategy that should respond positively.The main findings were as follows:(1)In the study of watershed nitrogen balance,the main nitrogen input in the Tiaoxi River Basin was chemical fertilizer nitrogen,which accounted for 73%of the total nitrogen input.The accumulation of nitrogen in the soil was caused by improper fertilization in a large number of farmland.The proportion of organic fertilizer caused by human and feces pollution in the basin was also heavier,with a total proportion of up to 15%.Biological nitrogen fixation,straw returning,and seed carrying were less nitrogen sources.Among the nitrogen output of the basin,the nitrogen output was mainly crop harvest,accounting for 89%of the total output nitrogen,and the proportion of runoff loss and leaching in nitrogen output was also higher.This was related to the existing natural environmental impacts and human factors,and had an impact on the nitrogen balance structure of the agro-ecosystem.The discussion of the nitrogen balance and transformation mechanism under different fertilization systems was to effectively reduce the nitrogen loss in the reservoir area and increased the nitrogen fertilizer.The utilization rate provided a theoretical basis.Therefore,the investigation of nitrogen balance under different fertilization systems in the Tiaoxi River Basin should be further studied.(2)The sources of non-point source pollution in domestic pollution,livestock and poultry breeding,aquaculture and planting,as well as the emission of total nitrogen(TN)and total phosphorus(TP)pollutants and their contribution rate were studied.The surface source in the basin was evaluated.The main sources and characteristics of pollution,the actual situation of each source of pollution was as follows:Among the sources of total nitrogen pollution,livestock and poultry farming was the largest source of pollution,accounting for 27%of the total contribution,followed by planting,accounting for 25%.Among the sources of pollution load of total phosphorus,livestock and poultry farming was the most important source of pollution,with a proportion of 49%.In summary,the source of non-point source pollution of nitrogen and phosphorus in the Tiaoxi River Basin was mainly livestock and poultry farming>rural domestic sewage>planting industry>aquaculture.The ecological security of water environment in the basin closely related to human factors.(3)This study analyzed the causes of the four major sources of pollution in the river basin,and concluded that the natural and man-made possibility of generating pollution sources.Analyzed the reasons for the status of their respective pollution sources from three aspects:plantation,livestock breeding,and rural life.Among them,the planting industry was mainly due to uncertain fertilization methods,planting models,field management measures,and pollution factors;the progress of regulations on animal husbandry in the long-term sustainable road was slow,the facilities for animal manure treatment are incomplete,and the use of There was still a long way to go before the improvement project can be comprehensively promoted in huge river basins.In the aquaculture,the environmental protection responsibilities of the competent authorities focus on prevention of light end pollution of tail water pollution;the current legal system was not perfect,and the basis for law enforcement was insufficient;the law enforcement and supervision model for tail water pollution prevention was incomplete.The source of domestic pollution was that there were many villages and towns in the river basin.The inter-regional rural sewage treatment regulations had not been unified and the residents of villages and towns in the study area were scattered.Most of them were environmental protection consciousness to be strengthened.(4)For different sources,analyzed pollution control strategies from planting,livestock and poultry breeding,domestic pollution,and other sources of pollution.In the planting industry,made recommendations on scientifically applying fertilizers and improving land use,and adjust the breeding area in livestock and poultry breeding.Layout,improvement of scientific and practical technology and legal supported for livestock and poultry farming,legal support,market supervision,improvement of sewage treatment utilization against domestic pollution sources,improvement of citizens’ environmental awareness and literacy,construction of a new model of environmental management in aquaculture in aquaculture,and further promotion of aquaculture ponds Standardization and ecological transformation,and vigorously improved the scientific and technological level of aquaculture.Suggestions for other governments and related departments started with clear division of functions and responsibilities,increased monitoring,improved ecological compensation mechanisms,cross-region arbitration within the river basin,and establishment of information disclosure and sharing mechanisms.Therefore,suggestions were made on the status of non-point source pollution in the Tiaoxi River Basin,provided support for the water environment and ecological safety and health of the Luxi River Basin,and provided a reference for future non-point source pollution control in related plain river networks.