| Soil is the basic resource for human existence and the important basis for agricultural development.Soil ecological security is the important basis for ensuring the whole ecological environment security and food security,and has important strategic significance for the sustainable development of the national economy.With the increasingly prominent phenomenon of non-grain use of cultivated land in China,the use of cultivated land has changed from grain production to a variety of agricultural management methods.On the one hand,it brings potential risks to national food security,on the other hand,some non-grain use of cultivated land will destroy water conservancy facilities and soil tillage layer,affecting the circulation and supply of soil nutrient,which will directly cause the changes of soil texture and subsurface microbial community structure,threatening soil ecosystem.Soil microbial diversity is an important part of soil productivity and an important support for soil ecological cycle.Defining the influence of non-grain use of cultivated land on soil microbial diversity,and rationally guiding and controlling the non-grain use of cultivated land play an important role in improving soil microbial diversity and ensuring the ecological cycle of cultivated land.However,most scholars focus on the effects of non-grain use of cultivated land on soil p H value,organic matter,tillage layer and heavy metal pollution,and have not found scholars to study the effects on soil microbial diversity.Secondly,in order to prevent the adverse effects of non-grain use of cultivated land on soil,most of the studies have proposed to adopt administrative instructions and compulsory measures,and have not found scholars propose specific governance measures from the perspective of economic benefits of farmers combined with government control.If the economic benefits of farmers are not considered,only through government administrative orders,farmers face both the direct loss and the indirect loss.Therefore,farmers have great opposition and the governance effect is not obvious.And for some poor villages,like Songyang county forced the elimination of tea planting,it will lead to the loss of infrastructure investment,the higher-level financial investment and the village collective will also be wasted,which is in contradiction with the consolidation of poverty alleviation achievements and may cause farmers return to poverty,which is not conducive to the implementation of the common prosperity strategy,and the development concept that lucid water and lush mountains are invaluable assets.Therefore,this paper intends to analyze the relationship among non-grain use of cultivated land and soil microbial diversity from the perspective of economic benefits,based on the mediating effect model,construct a theoretical analysis framework of“economic benefits of farmers--non-grain use of cultivated land--soil microbial diversity”.Finally,from the perspective of economic benefits of farmers,puts forward specific control measures to guide the non-grain management of cultivated land,and to improve soil microbial diversity.The main conclusions of this paper are as follows:On the theoretical level,this paper uses the theory of environmental economics,comparative incomes and human-land relationship to analyze the relationship among the economic benefits of farmers,non-grain use of cultivated land and soil microbial diversity from a theoretical level,and construct a analysis framework.Four research hypotheses are proposed based on theoretical and mechanistic analysis:(1)The economic benefits of farmers have a significant impact on soil microbial diversity.(2)The economic benefits of farmers have a significant impact on the non-grain use of cultivated land.(3)Different non-grain use of cultivated land has a significant impact on soil microbial diversity.(4)The non-grain use of cultivated land has a mediating effect between the economic benefits of farmers and soil microbial diversity.On the empirical level,this paper takes 10 typical cities in Zhejiang Province as research area,based on 68 plots,and constructs a mediating effect model according to the theoretical analysis framework.The conclusions are as follows:(1)On the whole,the economic benefits of farmers in Zhejiang Province had a significant negative impact on soil microbial diversity,that is,farmers do not pay attention to protecting lucid water and lush mountains when they get invaluable assets.However,different land use patterns have different effects on soil microbial diversity.(2)The economic benefits of farmers had a positive impact on the non-grain use of cultivated land,and through the control variables,the current basic farmland protection policy does not significantly inhibit the non-grain use of cultivated land.(3)The effects of different non-grain use methods on soil microbial diversity are different.Landscape seedling,fruit tree and tea planting,had a significant negative impact on soil microbial diversity,landscape seedling and fruit tree planting had a greater impact,tea planting had less impact,while vegetable planting can significantly contribute to the soil microbial diversity.(4)Non-grain use of cultivated land had a certain intermediary effect.The economic benefits of farmers had a significant negatively influence on soil microbial diversity through three kinds of non-grain use of cultivated land.The results show that non-grain use of cultivated land is an extremely important way for the economic benefits of farmers to indirectly affect soil microbial diversity.Based on the results,from the perspective of economic benefits of farmers,combined with government control,this paper puts forward specific measures as follows:(1)In order to improve economic benefits,farmers will choose non-grain use of cultivated land,thus affecting soil microbial diversity.The increase of land rent is an important factor to inhibit economic benefits at present.Therefore,it is necessary to develop a transfer price standard and dynamic monitoring mechanism,to keep land rent at a reasonable level,inhibit the non-grain use of cultivated land,and improve soil microbial diversity.(2)The research shows that the economic benefits of farmers is one of the important factors to promote the non-grain use of cultivated land.In order to reduce the income gap between grain planting and non-grain production,the government should link the planning control with the economic benefits of farmers,promoting the protection of soil microbial diversity.(3)The results show that not all non-grain use of cultivated land will negatively affect soil microbial diversity,and the degree of influence is also different.Therefore,it should be classified and controlled according to the damage degree of different non-grain use and the cost of production capacity recovery,to improve soil microbial diversity.(4)Establish the dynamic monitoring system of cultivated land protection to monitor the non-grain use of cultivated land and soil microbial diversity,and improve the soil microbial diversity by repairing soil quality through engineering and technical measures. |
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