本文从概念、理论及因素等方面对目前在城市化空间增长约束作用的特征进行了梳理,认为目前的研究存在着区域宏观尺度的把握较少、因素集成分析较少、缺乏直接针对城市用地本身与其他因素的相关关系分析等不足。笔者认为从约束角度开展对城市化空间增长上限的研究工作,关键是如何确定区域水资源安全容量、粮食安全下的耕地最小规模、可恢复条件下生态空间的最小规模或城市生产生活所需的最小生态空间规模等阈值,并提出城市化空间增长上限确定的方法和途径。

In this study, concepts of urbanized space, theories of growth ceiling of urbanized space, and factors of constraint, are reviewed. And the characteristics generated by the current environment and resources capacity in the process of urbanization and the relationships between them and growth of urban space are sorted. The existence of these problems directly affects the accuracy of comprehension of the binding mechanism for urban expansion process. Based on previous studies and the author's summarizing the relevant research results in recent phase, we think that, for carrying out the research on growth limit of regional urban space, from the perspective of constraints, the key is how to determine the maximum capacity of regional water security, the minimum size of farm land under food security, the minimum scale of ecological space under restoration or the minimum threshold of ecological space for living expenses and urban production. And we put forward that, taking a quantitative research as the core, taking the sustainable use of land resources and the stability of land-use system as a precondition, it should make comprehensive integration of the resistance relationships under the various elements, and then construct the overall space model of growth ceiling of regional urbanized space. In addition, during the quantitative evaluation, it also needs to consider two key issues, the results validation and the scale of analysis, and their impacts on the conclusions of analysis. By splitting the process, "binding effect-the threshold of resources and the environment-urban spatial growth cap", into a number of possible scenarios, and analyzing the trends of resources and environment, and the relationships between them and the growth of urbanized space, caused by ecological environment and soil and water resources, in each scenario, then it could carry out the analysis of the resources and environment constraints on urbanization.