Study On Ecological Costs And Benefits Of Supplementary Cultivated Land And Identification Of Future Priority Areas In China

In the past 20 years,China’s industrialization and urbanization have developed rapidly,and non-agricultural construction has occupied a large amount of high-quality cultivated land,which has posed a serious threat to national food security.In view of the continuous reduction of the amount of cultivated land,China began to implement a strict system of balance between the occupation and compensation of cultivated land,that is,"how much is occupied,how much is cultivated",which curbed the momentum of rapid reduction of cultivated land and maintained the red line of 1.8 billion mu of cultivated land.However,China’s economic and social development presents an uneven distribution pattern between the East and the West and the difference between the North and the South.The implementation of the related management method of cross-provincial adjustment of cultivated land balance has led to a stable number of cultivated land in China,significant changes in its location,and significant displacement of cultivated land,resulting in a series of ecological and environmental problems.In the process of implementing the balance of occupation and compensation policy,most of the new added farmland is converted from forest land and grassland,leading to increased soil erosion,increased water resource shortage,and loss of biodiversity in the region,affecting regional ecological security and the health level of ecosystem services.However,there is currently very little research focusing on the ecological cost and benefit effects of the implementation of China’s cultivated land occupation and compensation balance policy,which is extremely important for the synergistic balance between ecological protection and food security.In addition,how to minimize ecological cost in China’s supplementary cultivated land in the future also needs in-depth research.Therefore,this study is based on remote sensing data and uses spatial econometric analysis methods to detect the transfer types and spatial characteristics of new supplementary cultivated land in China in the past 20 years,revealing the main driving factors of new supplementary cultivated land.And the In VEST model and ecosystem service equivalent factor table were used to quantitatively evaluate the impact of China’s new supplementary cultivated land on various ecosystem services and its ecological costs and benefits,and identify the priority areas of China’s supplementary cultivated land in the future.The main conclusions of this study are as follows:(1)From 2000 to 2020,the total area of new supplementary cultivated land in China was 2125.2×10~4hm~2,which showed significant heterogeneity in spatial distribution.Before 2010,the key areas of new supplementary cultivated land were mainly located south of the Yellow River and the middle and lower reaches of the Yangtze River in China.After 2010,the center of gravity of new supplementary cultivated land gradually shifted from the central to the northwest,and Xinjiang,Heilongjiang and Inner Mongolia became the key areas of new supplementary cultivated land.In addition,forest land and grassland have always been the main source of new supplementary arable land in China.(2)The spatial differentiation characteristics of China’s new supplementary cultivated land are affected by the comprehensive influence of socio-economic,natural environment and regional policies.Among the socio-economic factors,the total power of agricultural machinery was positively correlated with the new supplementary cultivated land,that is,the progress of technology promoted the increase of cultivated land reclamation.Among the natural environmental factors,the increase in temperature provides the necessary heat energy for cultivated land reclamation in the north,and the center of gravity of China’s new supplementary cultivated land gradually shifts northward.Among the regional policy factors,the areas with reduced cultivated land are also the main source areas of new supplementary cultivated land due to the influence of the policy of cultivated land balance and the policy of ecological farmland return.(3)There were significant differences in the spatial distribution of changes in ecosystem services caused by new supplementary cultivated land in China.The value costs and benefits of ecosystem services in China’s new supplementary cultivated land was calculated through the In VEST model and equivalent factor table,among which the ecological degradation problems such as loss of raw material production value,reduction of carbon stock,and weakening of soil conservation caused by newly replenished arable land are mainly distributed in southern China,and the water yield reduction areas are concentrated in northern China.Areas of habitat quality degradation and loss of aesthetic landscape value are more widely distributed.Overall,the expansion of arable land in the past 20 years has led to a loss of 47.426 billion yuan in the total value of ecosystem services in China.The reason for this is that most of China’s new supplementary cultivated land comes from ecological land such as forest land and grassland,resulting in a significant decline in the value of various ecological services.Therefore,the policy of cultivated land to supplement balance should be further optimized,and at the same time the channels of cultivated land replenishment should be expanded to avoid cultivated land occupying land with better ecosystem functions such as forest land and grassland.(4)By considering the impact of cultivated land reclamation on various ecosystem services,the spatial distribution of ecological value costs and benefits in future cultivated land supplementation areas was evaluated.It is found that the priority areas of future supplementary arable land based on the value costs and benefits of supply,regulation,support and cultural services are concentrated in Northeast China.On this basis,the spatial distribution of potential ecological costs and benefits in the future supplementary cultivated land area is further explored,and the results show that the central and northeastern regions of Inner Mongolia should be preferred for future cultivated land reclamation in China.Therefore,it is necessary to make overall plans for the reserve resources of cultivated land,develop and utilize them according to local conditions,and prevent ecological deterioration and loss of ecological service value.