The Environmental Effects And Optimal Regulation Of Cropland Displacement In China

China is one of the fastest developing countries in the world in terms of economic development and also one of the countries with the fastest urbanization process.The rapidly growing economy and urbanization rate not only made China the world’s second largest economy,but also inevitably brought a series of problems such as sharp reduction in cropland area and deterioration of ecological environment.In order to curb the decreasing trend of cultivated land area and improve the ecological environment,China has introduced a series of cultivated land protection systems and implemented many ecological engineering,the most important of which is the balance system of occupation and compensation of cultivated land.After the State Council issued the"The measures for The Overall National Management of Inter Province Cropland Compensation"in 2018,it further improved the balance system of cropland occupation and compensation.This system not only stipulates the conditions and specific scale for implementing the system to be coordinated and arranged by the state,but also provides policy guidance for future cross provincial supplementary cultivated land.Under the influence of the above factors,the lost farmland in various regions is replenished in other places,ultimately resulting in changes in the layout of farmland,which is known as farmland displacement.The process of cultivated land displacement can have environmental impacts on both reduced and increased cultivated land areas.The aim of this study is to explore the environmental effects of cultivated land displacement in China and provide relevant suggestions for the spatial layout policy of cultivated land.This paper takes Chinese Mainland as the research area to explore the environmental effects of cultivated land displacement and the policy recommendations for the spatial distribution of cultivated land.Analyze the phenomenon and influencing factors of cropland displacement in China by combining the changes in the number and location of cropland from 2000 to 2015 with the direction and distance of cropland center of gravity migration.Using the ESV evaluation system and combining the differences in the quantity of cultivated land inputs in different regions,calculate the ESV of cultivated land per unit area in each province;Based on this,the ecological value changes caused by increasing or decreasing one unit of cropland in different regions can be calculated and analyzed through the types and data of ecological land converted into cropland in each province.Finally,suggestions can be provided for the spatial layout policy of cropland in China.The research results indicate that:(1)From 2000 to 2015,the cumulative decrease in cropland area in China exceeded 40000 km~2,with the most significant decrease in East China and the most significant increase in Northwest China.The center of gravity of cropland in China has been continuously moving towards the northwest for 15 years,with a cumulative migration distance of 54km.Under the influence of economic development and policy regulation,the spatial layout of cropland,which was previously determined by the natural environment,has been changed,presenting a new pattern of decreasing in the east and increasing in the west.(2)The 9 types of service functions constitute the positive value of China’s cropland ecosystem,but due to the high input of cropland and irrigation water consumption,this has resulted in two negative values:environmental pollution and water resource consumption.Combining the two,we can obtain the ESV per unit area of cropland in China;The comparison shows that the ESV of cultivated land in East China is the lowest,while the northwest and southwest regions have the highest.(3)In the past 15 years,the northwest region has experienced the highest increase in ESV,with a total of 236.4 billion yuan;The largest decrease occurred in East China,with a total of 79.6 billion yuan.The total ecological land occupied by cropland nationwide is 169050km~2,with an ESV loss of up to 548 billion yuan.Forest land ranks first among various ecological land types with an area of 80606km~2.From a regional perspective,grasslands have the most cropland in North China and Northwest China,while the rest of the region is dominated by forest land.From a spatial perspective,the ESV loss per unit area of ecological land in the southern part of China is much higher than that in the northern part.Shanghai has the highest ESV loss among provincial administrative regions,while the southwestern region has the highest ESV loss due to the occupation of cropland,with a total loss of 129.6billion yuan,with the lowest being 39.2 billion yuan in the northern region.(4)Among the provincial-level administrative regions in China,the ESV loss caused by the addition of one unit of cropland in Shanghai region reached 5.27million yuan,ranking first in the country,with Xinjiang Autonomous Region having the lowest ESV loss of 730000 yuan;From a regional perspective,the ecological losses caused by newly added farmland in the northwest region are generally low,with the highest in East China.The reason for this phenomenon is that the newly added farmland in the northwest region mainly comes from grasslands and unused land,while in East China,it is mainly forest land and water bodies.Therefore,it can be seen that the reduction of cropland in East China will reduce ESV losses if replenished in other regions,while the reduction of cropland in the Northwest region will cause high ESV losses if replenished in any other region.Reducing cropland in various regions of the country and increasing it in the Northwest region can reduce ESV losses.Policy recommendations for the spatial layout of cropland in China based on the ESV losses caused by the addition of new units of cropland in various provinces:firstly,establish a diversified ecological compensation mechanism;2、Improve the balance system of cropland occupation and compensation based on ecological impact.