Spatiotemporal differences and convergence of urban industrial land use efficiency for China's major economic zones

Based on an SBM model, this paper first analyzes the spatial differences of urban industrial land use efficiency (UILUE) in the six main economic zones of China. Then, we analyze the dynamic changes in the urban industrial land's total factor productivity (UILTFP) by using the Malmquist productivity index approach, and we examine the UILTFP's convergence. The results show that the Pearl River Delta and the Yangtze River Delta have a higher UILUEs but show downward trends in UILTFPs. The other four zones, Beijing-Tianjin-Hebei, Chengdu-Chongqing, Guanzhong-Tianshui and the Central Plains, show poorer UILUEs but have upward trends in UILTFPs. A significant excess supply of industrial land and labor exists in all six zones, and the zones in economically developed areas perform better in industrial output. The results of the convergence test do not support sigma-convergence but support conditional beta-convergence for all zones. These results indicate that the gaps in the UILTFP of industrial land in all six zones, in fact, do not narrow, and the UILTFPs of cities will converge to their own steady states. The regression results of the influencing factors show that the urbanization rate should be increased in the Pearl River Delta and reduced in Beijing- Tianjin-Hebei. The Yangtze River Delta and Chengdu-Chongqing should pay more attention to the problem of industrial labor surplus, and the Pearl River Delta should reduce the proportion of industrial output. All zones should focus on improving the quality of the industrial economy and the land use intensity.