Theoretical Analysis and Empirical Study of Urban Expansion Based on the Marginal Principle

Rapid urban expansion places unprecedented pressure on urban land management. Optimization of urban spatial layout has become a theoretical proposition and a practical problem associated with urban expansion. Thus, by using the social value measurement model, equivalent factor method, and marginal benefit measurement model, in this paper, we analyze the land resource allocation mechanism, efficiency loss, and reasonable interval. The study results are as follows: (1) Theoretical analysis shows that there are three ranges of land use for urban expansion in China—ideal, moderate and extreme—and it is reasonable to control the amount of land used for urban expansion within the moderate range. (2) Value measurement reveals that the marginal social value and marginal ecological value of cultivated land in Xuzhou show an overall upward trend. From the perspective of the constant price in 2018, the marginal social value increased from CNY 4.91 million/hm2 in 2005 to CNY 14.31 million/hm2 in 2018, while the marginal ecological value increased from CNY 9513.60/hm2 in 2005 to CNY 13,629.70/hm2 in 2018. (3) Empirical analysis shows that when the marginal value of land as cultivated land and construction land is equal, the actual scale of occupied agricultural land is 51,887.23 hm2, of which 25,686.67 hm2 of cultivated land is converted into construction land, sacrificing the social value of farmland, and 12,281.70 hm2 of cultivated land is converted into construction land, ignoring the non-market value of land. Based on the perspective of the marginal principle, in this paper, we construct a model of urban expansion land use allocation and define reasonable intervals for urban expansion land use so as to provide a quantitative reference and decision-making basis for urban expansion governance.