Agricultural land, as an important carbon source, has produced about 20% of carbon dioxide globally. The calculation and spatial-temporal distribution of carbon emissions resulting from agricultural land utilization (ALU) has attracted a great deal of attention from scholars. Most of the existing literature widely agrees that China’s carbon emissions from ALU showed significant regional discrepancies, but rarely pays attention to the evolutionary characteristics of the discrepancies. This study calculated the total carbon emissions from ALU based on six kinds of carbon emissions sources in the 31 provinces of mainland China, which showed obviously different characteristics in terms of their abundances of agricultural land resources, relative scarcities of production factors, levels of science and technology and economic prosperity. We then analyzed the evolutionary process and characteristics of regional discrepancies in carbon emissions from ALU at the national level and regional level with the method of kernel density estimation. The key results demonstrated the following: (1) The carbon emissions from ALU in the whole country and the eastern, central and western regions of China have increased sharply during the study period. From 2000 to 2015, the carbon emissions from ALU in the whole of China, the eastern region, central region, and western region were increased by 2626.11 (10⁴ tons), 441.32 (10⁴ tons), 1054.45 (10⁴ tons), and 1130.3 (10⁴ tons), respectively, with an average annual growth rate of 2.75%, 1.29%, 3%, and 4.35%, respectively; (2) The scale of carbon emissions from ALU showed significant spatial disparities at the regional and inter-provincial levels. From 2000 to 2015, the central region had the highest carbon emissions from ALU, while the eastern and western regions had the second and third highest carbon emissions; (3) The distribution curves of carbon emissions from ALU in the whole country and each region all moved in the right direction gradually during the study period, and the width of the curves increased, indicating the regional discrepancies of carbon emissions from ALU was expanding at different spatial scales. Distribution curves of carbon emissions from ALU in the eastern, central and western regions all showed a “multi-polar” differentiation phenomenon in 2000, while presented a “tri-polar”, “bipolar” and “multi-polar” division in 2015, respectively.

Eco-efficiency of arable land utilization (EALU) emphasizes efficient coordination between land use systems and ecosystems. It is therefore of great significance for agricultural sustainability based on the systematic assessment of EALU. This study took carbon emissions and non-point source pollution resulting from arable land utilization into the measurement system of EALU, and a super-SBM model, kernel density estimation and Tobit regression model were used to analyze regional differences and influencing factors of EALU for 31 provinces in China from 2000 to 2019. The results showed that there was an upward trend in EALU in China from 0.4393 in 2000 to 0.8929 in 2019, with an average annual growth rate of 4.01%. At the regional level, the EALU of three categories of grain functional areas generally maintains an increasing trend, with the highest average value of EALU in main grain marketing areas (MGMAs), followed by grain producing and marketing balance areas (GPMBAs) and main grain producing areas (MGPAs). There are obvious differences in EALU among provinces, and the number of provinces with high eco-efficiency has increased significantly, showing a spatial distribution pattern of “block” clustering. In terms of dynamic evolution, kernel density curves reflect the evolution of EALU in China and grain functional areas with different degrees of polarization characteristics. The results of Tobit regression show that natural conditions, financial support for agriculture, science and technology inputs, level of industrialization, agricultural mechanization, and the living standards of farmers are significant factors resulting in regional disparities of EALU. Therefore, this study proposes the implementation of differentiated arable land use/agricultural management strategies to improve the sustainable utilization of arable land.

The development of social production and the agglomeration of the urban population have brought tremendous pressure to transportation infrastructure. However, the impacts of transportation development on urban land use systems have not been well investigated. Under the pressure of limited land resources, the impact of transportation infrastructure on urban land use efficiency (ULUE) is receiving increasing attention from scholars and needs to be explored. By collecting panel data from 30 regions in China from 2003 to 2018, in this study we constructed a spatial Durbin model and a panel threshold regression model to explore the spatial spillover effects and threshold effects of transportation infrastructure on ULUE. The most obvious findings emerging from this study are that (1) ULUE is not randomly distributed over different regions in China, but has an obvious positive spatial correlation; (2) transportation infrastructure has significant positive direct and spatial spillover effects on ULUE and the direct effects of transportation infrastructure (0.823) are significantly stronger than the spatial spillover effects (0.263); (3) the impact of transportation infrastructure on ULUE has a significant double threshold effect, and the threshold values are 4.520 and 6.429 respectively, and with the improvement of transportation infrastructure, its marginal effects on ULUE show a downward trend. This paper provides theoretical support for policymakers to achieve cross-regional cooperation on land use and transportation infrastructure construction and inspirations for sustainable development.

Researching the impact of factor flow on urban land use efficiency (ULUE) is significant in alleviating the contradiction between the accelerated promotion of urbanization and the inefficient use of urban land. This paper theoretically analyzes the impact mechanism of the flow of the three major factors of production—land, capital, and labor—on ULUE. On this basis, taking 54 cities in the urban agglomeration in the middle and lower reaches of the Yangtze River in China as the research object, the stochastic frontier model, fixed effect model, and K-means clustering method are used to empirically analyze the impact of the flow of labor, capital, and land on ULUE. The heterogeneous effect of factor flow on ULUE in different urbanization stages is also discussed. The results are as follows: (1) Labor flow and capital flow play a significant role in promoting ULUE; land flow plays the opposite role. (2) With the continuous improvement of the level of urbanization, the promotion effect of labor flow first decreases and then increases, while the promotion effect of capital flow continues to decrease, and the inhibitory effect of land flow is significant in the initial stage and expansion stage of urbanization, and the effect increases gradually, but it is not significant in the mature stage. (3) The level of urbanization has an obvious threshold effect on factor flow. There are single thresholds for labor and land flow, and there is a double threshold for capital flow. Research conclusions: we should continue to promote the market-oriented reform of factors, break the institutional shackles which restrict the free flow of factors, implement policies according to the city and the stage, and give full play to the positive impact of factor flow on ULUE.

Local governments in China have decision-making authority over urban land use, and their level of environmental attention influences the green use of urban land. However, the impact of local government environmental attention on urban land green use efficiency and its mechanisms remain unclear. This study utilizes panel data from 284 cities from 2003 to 2020 in China and employs fixed effects models and mediation analysis to investigate the pathways through which local government environmental attention affects urban land green use efficiency. The main results are as follows: (1) Through a series of significance tests, local government environmental attention has a significant positive influence on urban land green use efficiency in cities. (2) Further research suggests that both the quantity and quality of industrial structure upgrading act as intermediaries between local government environmental attention and urban land green use efficiency, while the rationalization of industrial structure plays a partial masking role rather than acting as an intermediary. (3) Furthermore, a regional heterogeneity analysis indicates that the impact of local government environmental attention on urban land green use efficiency is significant in the central region but not in the eastern and western regions. Based on these research findings, this study provides valuable policy insights aimed at contributing to green land use and sustainable development in Chinese cities.