| As the main carrier of China’s economic development,land is closely linked to the direction and development potential of urban development.With the acceleration of urbanisation,the demand for land has gradually increased,giving rise to land use problems such as contradictions in land supply and demand,and sloppy land use.Since the reform and opening up,China has formed 19 urban agglomerations such as Beijing-Tianjin-Hebei,Yangtze River Delta and Pearl River Delta.Urban agglomerations are the theme of the future layout of urbanisation and the core areas of economic development,playing a driving role in development.Beijing-Tianjin-Hebei,Yangtze River Delta and Pearl River Delta have taken the lead in forming urban agglomerations that are influential and play a driving role in the social economy.Land use efficiency is the main manifestation of the level of regional development,and how to effectively improve the land use efficiency of urban agglomerations is an effective way to alleviate land use problems and promote urban economic development.Taking the three major urban agglomerations(Beijing-Tianjin-Hebei,Yangtze River Delta and Pearl River Delta)in China as an example,this paper measures land use efficiency based on land use efficiency evaluation indicators using the SBM-Undesirable model;introduces the Malmquist index,Gini coefficient,kernel density function and traditional Markov chain to explore the dynamic changes of land use efficiency in time and space;uses the Tobit model to empirically test the factors influencing land use efficiency in the three major urban agglomerations from 2005 to 2020,and propose a path to optimize land use in urban agglomerations to provide reference for land use activities during the development of urban agglomerations.The main research findings are as follows:(1)From a static perspective:(1)There are differences in the land use efficiency values of the built-up areas of China’s three major urban agglomerations in 2020.From the perspective of urban agglomerations,the land use efficiency values are,from highest to lowest,those of the Pearl River Delta urban agglomeration(1.153),the Yangtze River Delta urban agglomeration(0.884)and the Beijing-Tianjin-Hebei urban agglomeration(0.731).From a city perspective,there are 21 cities with relatively effective land use efficiency,with Beijing-Tianjin-Hebei accounting for six,the Yangtze River Delta for 10 and the Pearl River Delta for five;there are 23 cities with relatively effective pure technical efficiency;and only one city with relatively effective scale efficiency.(2)The 27 cities with land use efficiency values less than 1 in 2020 all have input-output redundancy.The analysis shows that the redundancy of capital input,land input and non-desired output accounts for a large proportion,which is mainly due to the disorderly expansion of cities and the insufficient level of environmental management.(2)From a dynamic point of view:(1)Analysis of both the distribution characteristics and the annual average change pattern of cities with different land use efficiency shows that the degree of improvement in total factor productivity is uneven between cities and there is great individual variability;the main factor affecting total factor productivity in the study area is technological change.(2)The three major urban agglomerations account for 16 cities with high land use efficiency,13 cities with medium efficiency and 19 cities with low efficiency in the built-up areas.Among them,Beijing-Tianjin-Hebei,Yangtze River Delta and Pearl River Delta accounted for15.4%,30.8% and 66.7% of the high-efficiency cities in land use respectively.There are 17 purely technically efficient cities,most of which are located in the Yangtze River Delta city cluster.There are six scale efficiency high efficiency cities,accounting for 12.5% of the total.(3)There is still room for growth in other efficiency-valued cities.The Gini coefficient is used to characterise the differences in land use efficiency in the study area.It can be seen that the overall Gini coefficient is on a downward trend,and the three major urban agglomerations have developed in a balanced manner overall during the study period.From the kernel density curve,the overall leftward shift of the kernel density distribution curve;the peak in 2015 is the highest and the peak in 2020 is the lowest,with the tail on the right side of the curve continuously shortening and thickening,indicating that the land use efficiency values are volatile and develop in a multi-polar trend.From the traditional Markov chain,the type shift of land use efficiency has a certain stability;the probability of maintaining land use efficiency at low and high levels is the greatest;there is a cross-level shift of land use efficiency,but the probability is small.(3)The regression of influencing factors found that the level of economic development,the level of urbanisation,the level of industrial structure and the level of public services have a significant inhibiting effect on the land use efficiency of urban agglomerations;among them,the level of information technology and the level of transportation play a significant positive role for Beijing,Tianjin and Hebei.(4)Based on the characteristics and problems of the development of land use efficiency in the three major urban agglomerations reflected by the study,the optimization suggestions of clarifying the development orientation and exploring the mechanism of synergistic development of urban agglomerations,promoting green development and strengthening ecological environmental protection of urban agglomerations,and reasonably promoting urbanization and improving the quality of land development of urban agglomerations are proposed around positioning,synergy and ecology,with a view to realizing the unification of economic,social and environmental effects of land use. |
