Impact Of Agricultural Agglomeration On Agricultural Non-point Source Pollution

In recent years,China's agricultural development has achieved remarkable achievements,but it is also facing a series of environmental problems such as excessive consumption of agricultural resources,deterioration of the ecological environment and aggravation of agricultural pollution.It is imperative to strengthen the prevention and control of agricultural non-point source pollution and improve the agricultural pollution.At the same time,“constructing modern agricultural industrial system,developing various forms of moderate scale operation,realizing the organic connection between small farmers and modern agricultural development” has been emphasized in the nineteen major reports of the party,and the rational agricultural agglomeration and cluster development have gradually become an effective choice to increase output and modernize the development of agriculture.Then,will agricultural agglomeration bring further agricultural non-point source pollution? Is there any connection between agricultural agglomeration and agricultural non-point source pollution? Theoretically,industrial agglomeration has a complex impact on its internal and external environment,and it can generate positive externalities or negative externalities.However,there are many studies on the relationship between industrial agglomeration and pollution,while the research on agriculture level is less at present.What is the impact of agricultural agglomeration on agricultural non-point source pollution? Clarifying the relationship between the gricultural agglomeration and agricultural non-point source pollution will help to grasp its association characteristics,analysis of the environmental effects of modern agricultural agglomeration and it also has profound guiding significance for improving agricultural non-point source pollution and speeding up the modernization process of agricultural and rural areas.First of all,combating related research and existing theories at home and abroad on agricultural agglomeration,agricultural non-point source pollution and the relationship between industrial agglomeration and environmental pollution which are taken as the research object in this paper;Secondly,the theoretical framework and theoretical model of the relationship between agricultural agglomeration and agricultural non-point source pollution are constructed on the basis of defining the connotation of agricultural agglomeration and agricultural non-point source pollution,and then put forward the research hypothesis;Thirdly,this study calculate the level of agricultural agglomeration and the emissions ofagricultural non-point pollutants in every Chinese prefecture-level cities by using the panel data of 337prefecture-level cities in China,and then the spatial and temporal characteristics of agricultural agglomeration and agricultural non-point source pollution are revealed through GIS technology to comparison and analysis their relationship preliminarily;Finally,according to the observed threshold characteristics between agricultural agglomeration and agricultural non-point source pollution,threshold regression model is further constructed to investigate the threshold effect of agricultural agglomeration level on agricultural non-point source pollution.The main contents are as follows:1.The theoretical analysis suggests that agricultural agglomeration can affect agricultural non-point source pollution by scale effect,structure effect,technical effect,social effect and cumulative effect.The impact of agricultural agglomeration on the environment is complex and constantly changing,with the improvement of the degree of agricultural agglomeration,the negative environmental externalities of each effect are more significant,while with the increase of agricultural agglomeration,some negative environmental externalities will be weakened.Therefore,this study suggests that there is a nonlinear relationship between agricultural agglomeration and agricultural non-point source pollution and assumes that agricultural agglomeration has a threshold effect on agricultural non-point source pollution,and when the level of agricultural agglomeration is raised to a certain extent,the worsening situation of pollution will be improved.2.Agricultural agglomeration and COD,TN,TP agricultural non-point source pollution showed different distribution characteristics and ange rules in temporal variation,spatial distribution,spatial correlation and spatial trends.There are different spatiotemporal characteristics between agricultural agglomeration and agricultural non-point source pollution,therefore,the research hypothesis is preliminarily confirmed from the perspective of intuition.3.Agricultural agglomeration has single threshold effect on COD,TN and TP agricultural non-point source pollution,there is a nonlinear relationship between agricultural agglomeration and agricultural nonpoint source pollution.The influence of agricultural agglomeration on COD,TN and TP agricultural nonpoint source pollution shows the variation characteristics of the first half of the inverted U curve,and the emissions of agricultural non-point source pollution increases monotonously with the increase of agricultural agglomeration level,howere,in the process of increasing,there is a turning point which is alsocalled the threshold value,beyond this threshold,the growth rate of agricultural non-point source pollution emissions slowed down,which confirms the hypothesis of this paper ulteriorly.4.The change between agricultural agglomeration and the emissions of three agricultural non-point sources pollution has two stages.It depends on the intensification and restriction of the scale effect,structure effect,technical effect,social effect and cumulative effect on the emissions of agricultural nonpoint sources pollution which is produced by agricultural agglomeration and it is reflected in the concrete agricultural production behavior.With the increase of agricultural agglomeration degree,the effect of each effect is obvious and the level of pollution is increased significantly through the increase of resource consumption,the entry of high agricultural non-point source pollution industries and the increase of the cumulative effect of pollution projects,however,the inhibition ability of pollution emission is improved and the external effect of negative environment is weakened through the agricultural production practices such as scale management and and the extensive use of green production technology at the stage of crossing the threshold.5.The agricultural economic level and agricultural production conditions aggravate the COD,TN and TP agricultural non-point source pollution to some extent;and there is a significant positive correlation between the structure of animal husbandry industry and the COD,TP agricultural non-point source pollution;environmental regulation has a positive correlation with COD and TP agricultural non-point source pollution,the effect of environmental governance is not remarkable in the current China;the improvement of producer quality can affect farmers' production behavior and improve the agricultural environment;and the regression results of the plantation structure on the three kinds of agricultural nonpoint source pollution are not significant.6.The effect of agricultural agglomeration on pollution reduction of COD agricultural non-point source pollution is weak.From the proportion of prefecture-level cities which are at the stage of crossing the threshold,the proportion is relatively small for COD compared with TN and TP,which shows that agricultural agglomeration has strong positive correlation with COD agricultural non-point source pollution in most regions and there are relatively few prefecture-level cities where the positive correlation becomes weak.