How Does Urban Shrinkage Affect Land Use Efficiency?A Case Study of Shrinking Cities in Northeast China

The effect of urban shrinkage has gradually become a new topic.Theoretically,urban shrinkage may exert great influence on land use efficiency(LUE)through various urban subsystems,but there is currently limited research examining these pathways.Using the Super-SBM-Undesirable model and the Structural Equation Model(SEM),this study calculates the LUE of shrinking cities in Northeast China and simulates the process of urban shrinkage affecting LUE.To quantify the process of urban shrinkage affecting LUE,three mediation variables,namely the economy,public services,and innovation,are used as latent variables to apply SEM.The results show that urban shrinkage will affect LUE through a direct path and indirect paths.In the direct path,urban shrinkage leads to an improvement in LUE.In the indirect paths,the economy and innovation will transmit the negative effect of urban shrinkage on LUE,while public services will reverse this effect.An important contribution of this study is that it quantifies the paths of urban shrinkage affecting LUE,thereby expanding the understanding of urban shrinkage effect and laying a foundation for the sustainable development of shrinking cities.

A Comparative Study on the Land Use Efficiency of Three Urban Agglomerations-Based on the Three-Stage DEA Model

This paper uses a three-stage DEA model to measure the land use efficiency of the three major urban agglomerations in the Yangtze River Delta,Beijing-Tianjin-Hebei,and the Pearl River Delta from 2007 to 2018.The following conclusions are drawn through research:first,the urban land use efficiency of the three major urban agglomerations in the Yangtze River Delta,Beijing-Tianjin-Hebei,and the Pearl River Delta all showed a downward trend,with the rates of decline being 6.06%,2.86%,and 24.34%respectively.In particular,the Pearl River Delta urban agglomeration had the largest decline.Second,the overall urban land use efficiency of the Beijing-Tianjin-Hebei urban agglomeration is relatively high,and the amount of redundancy is relatively small.The rate of decline is significantly lower than the urban land use efficiency of the two major urban agglomerations in the Yangtze River Delta and the Pearl River Delta.The land use efficiency of the Yangtze River Delta and Pearl River Delta urban agglomerations is in a state of continuous decline.Third,the proportion of cities with the effectiveness of returns to scale of urban land use efficiency in the three major urban agglomerations has decreased by 10.53%,10%,and 33.34%,respectively.The Pearl River Delta has the largest decline.Fourth,the land use efficiency of the Yangtze River Delta urban agglomeration is quite different.The central-peripheral phenomenon is evident for the Beijing-Tianjin-Hebei urban agglomerations and the Pearl River Delta urban agglomerations.

Urban Land Use Efficiency and Contributing Factors in the Yangtze River Delta Under Increasing Environmental Restrictions in China

Evaluating urban land use efficiency(ULUE) provides insights into the interactions between land use systems and their external environment. Specifically, changes in ULUE are important for monitoring urban transformation in developing countries. In this study, using a traditional input-output index model, we incorporated slack-based measurements and undesirable outputs into a SBM-UN(slack-based measure-undesirable) model to investigate ULUE within the context of increasing environmental restrictions in China. The model was used to estimate the ULUE of 26 cities in the highly developed urban agglomeration of the Yangtze River Delta from 2000 to2018. The average ULUE in the Yangtze River Delta was relatively low compared to that of developed city regions in the European Union(EU) and North America and exhibited a U-shaped curve over the study period. Incorporating undesirable outputs, such as environmental pollution, into the model reduced ULUE by 19.06%. ULUE varied spatially, with the kernel density estimation exhibiting a bimodal distribution. Efficiency decomposition analysis showed that scale efficiency made a greater contribution to ULUE than pure technical efficiency. Based on our findings, recommended approaches to improve ULUE include optimizing factor allocation, reducing undesirable outputs, and increasing the effective output per land unit. The study suggests that ULUE and the SBM-UN model are useful planning tools for sustainable urban development.

Efficiency of Land Utilizationand Urbanization Progress of China

Urbanization is a process that is undergoing all over the world, which will speed up in the forthcoming years, especially in China as the boom of economy. On average, urbanization level is not only depended on the speed, but theefficiency, particularly efficiency of using land resource which affects urbanization directly. This paper provided status quo of land resource utilization efficiency, indictors, methods and factors, and illustrated the reference of well land utilization, aiming at fostering urbanization in China.

Dynamic transfer and driving mechanisms of the coupling and coordination of agricultural resilience and rural land use efficiency in China

The joint study of agriculture and rural areas is of great significance for safeguarding agricultural development,revitalizing rural areas,and enhancing farmers'well-being.This paper aims to assess the spatiotemporal evolution characteristics of the coupling and coordination degree of agricultural resilience and rural land use efficiency and their dynamic transfer law and driving mechanisms,based on panel data of 31 provinces(municipalities and autonomous regions)in China from 2010 to 2020.The results showed:(1)Good coupling and coordination of agricultural resilience and rural land use efficiency,with reduced temporal differentiation degrees between regions;(2)Significant spatial autocorrelation between the overall coupling and coordination degrees of agricultural resilience and rural land use efficiency,forming cold spot and hot spot spatial patterns in the western and eastern parts,respectively,with a central transition area;(3)A spillover effect of the dynamic transfer process,with a manifested specific law as"club convergence","Matthew effect",and progressive development characteristics;(4)The key roles of the natural,social,economic,and policy indicators in the coupling and coordination development process of agricultural resilience and rural land use efficiency.However,the selected indicators showed substantial spatial differences in their influences on the coupling and coordination process between provinces.

Economic Analysis Study of Agricultural and Solar Complementary System

Agro-photovoltaic complementary system(APCS)is an innovative land use model combining agricultural production with photovoltaic power generation,aiming to realize dual land use and improve land use efficiency and economic benefits by installing photovoltaic panels on farmland.With the growth of global energy demand and the intensification of climate change,agro-photovoltaic(APV)systems have received widespread attention as a sustainable energy solution.Studies have shown that agro-photovoltaic systems exhibit significant economic benefits in different regions and crop types.Through reasonable system design and optimization,the agricultural and photovoltaic complementary system is not only technically feasible,but also has significant economic advantages,which provides a strong support for achieving the goal of sustainable development.

Technical efficiency and its determinants of the various cropping systems in the purple-soiled,hilly region of southwestern China

This study examines the technical efficiency(TE) differences among typical cropping systems of smallholder farmers in the purple-soiled hilly region of southwestern China.Household-,plot-,and crop-level data and community surveys were conducted to explore TE levels and determinants of typical cropping systems by using a translog stochastic frontier production function.Results indicate significant difference in TE and its determinants among cropping systems.The mean TEs of the rice cropping system(R),the rice-rape cropping system(RR),the rice-rape-potato cropping system(RRP),and the oil cropping system(O) are0.86,0.90,0.84,and 0.85,respectively,which are over 1.17 times higher than those of the maize-sweet potato-other crop cropping system(MSO) and the maize-sweet potato-wheat cropping system(MSW) at0.78 and 0.69,respectively.Moreover,Technical inefficiency(TIE) of different cropping systems is significantly affected by characteristics of the household as well as plot.However,the impact of land quality,mechanical cultivation conditions,crop structure,farming system,farm radius,household type,cultivated land area per capita,and annual household income per capitalon TIE vary by cropping system.Additionally,output elasticity of land,labor,and capital,as a group,is greater than the one of agricultural machinery and irrigation.Finally,when household-owned effective agricultural labor is at full farming capacity,optimal plot sizes for the R,RR,RRP,MSO,MSW,and 0 cropping systems are 1.12hm^2,0.35 hm^2,0.25 hm^2,2.82 hm^2,1.87 hm^2,and 1.17hm^2,respectively.

Water, land, and energy use efficiencies and financial evaluation of air conditioner cooled greenhouses based on field experiments

High temperature and humidity can be controlled in greenhouses by using mechanical refrigeration cooling system such as air conditioner(AC)in warm and humid regions.This study aims to evaluate the techno-financial aspects of the AC-cooled greenhouse as compared to the evaporative cooled(EV-cooled)greenhouse in winter and summer seasons.Two quonset single-span prototype greenhouses were built in the Agriculture Experiment Station of Sultan Qaboos University,Oman,with dimensions of 6.0 m long and 3.0 m wide.The AC-cooled greenhouse was covered by a rockwool insulated polyethylene plastic sheet and light emitting diodes(LED)lights were used as a source of light,while the EV-cooled greenhouse was covered by a transparent polyethylene sheet and sunlight was used as light source.Three cultivars of high-value lettuce were grown for experimentation.To evaluate the technical efficiency of greenhouse performance,we conducted measures on land use efficiency(LUE),water use efficiency(WUE),gross water use efficiency(GWUE)and energy use efficiency(EUE).Financial analysis was conducted to compare the profitability of both greenhouses.The results showed that the LUE in winter were 10.10 and 14.50 kg/m^(2) for the AC-and EV-cooled greenhouses,respectively.However,the values reduced near to 6.80 kg/m^(2) in both greenhouses in summer.The WUE of the AC-cooled greenhouse was higher than that of the EV-cooled greenhouse by 3.8%in winter and 26.8%in summer.The GWUE was used to measure the total yield to the total greenhouse water consumption including irrigation and cooling water;it was higher in the AC-cooled greenhouse than in the EV-cooled greenhouse in both summer and winter seasons by almost 98.0%–99.4%.The EUE in the EV-cooled greenhouse was higher in both seasons.Financial analysis showed that in winter,gross return,net return and benefit-to-cost ratio were better in the EVcooled greenhouse,while in summer,those were higher in the AC-cooled greenhouse.The values of internal rate of return in the AC-and EV-cooled greenhouses were 63.4%and 129.3%,respectively.In both greenhouses,lettuce investment was highly sensitive to changes in price,yield and energy cost.The financial performance of the AC-cooled greenhouse in summer was better than that of the EV-cooled greenhouse and the pattern was opposite in winter.Finally,more studies on the optimum LED light intensity for any particular crop have to be conducted over different growing seasons in order to enhance the yield quantity and quality of crop.

Comment on Marx's Theory of the Law of Diminishing Land Fertility

Marx＇s theory of the law of diminishing land fertility is an indispensable part of Marx＇s theory of rent. Marx not only denied the non-scientific component of the theory, but also affirmed the scientific component of the theory. China＇s theoretical circles have held a total negative attitude towards the theory for a long term, which has brought serious consequences to research on agricultural economic theory and agricultural production practice. Comprehensively understanding the scientific connotation of Marx＇s theory of the law of diminishing land fertility has extremely important theoretical and practical significance for reducing the blindness of land investment and improving the investment efficiency of land.

Regional Differences and Optimal Allocation of Cultivated Land Utilization Benefits Based on Improved TOPSIS Method:A Case Study of Guangxi

Taking 14 prefecture-level cities in Guangxi as an object,this paper explored the difference of cultivated land utilization efficiency in Guangxi,comprehensively evaluated the economic,social,and ecological aspects,and analyzed the regional differences in cultivated land use efficiency in Guangxi from 2005 to 2018 based on the improved TOPSIS method.By studying the quantitative change trends and spatial differences of the utilization benefit of cultivated land resources in Guangxi,it came up with recommendations for optimizing the allocation of cultivated land from the quantity and quality of cultivated land.It is intended to provide a scientific and theoretical reference for improving the use efficiency of cultivated land in Guangxi.

Spatiotemporal mismatch of land use functions and land use efficiencies and their influencing factors:A case study in the Middle Reaches of the Yangtze River,China

Identification of the spatial mismatch between land use functions(LUFs)and land use efficiencies(LUEs)is essential to regional land use policies.However,previous studies about LUF-LUE mismatch and its driving factors have been insufficient.In this study,we explored the spatiotemporal mismatch of LUFs and LUEs and their influencing factors from 2000 to 2018 in the Middle Reaches of the Yangtze River(MRYR).Specifically,we used Spearman correlation analysis to reveal the trade-off relationship between LUFs and LUEs and determine the direction of the influencing factors on the LUF-LUE mismatch,adopted spatial mismatch analysis to measure the imbalance between LUFs and LUEs,and used the geographical detector model to analyze the factors influencing this spatial mismatch.The results showed that production function(PDF),living function(LVF),ecological function(ELF),agricultural production efficiency(APE),urban construction efficiency(UCE),and ecological services efficiency(ESE)all displayed significant spatial heterogeneity.The high trade-off areas were widely distributed and long-lasting in agricultural space and urban space,while gradually decreasing in ecological space.Wuhan and Changsha showed high spatial mismatch coefficients in urban space,but low spatial mismatch coefficients in agricultural space.Hunan generally presented high spatial mismatch coefficients in ecological space.Furthermore,the interaction of the proportion of cultivated area and transportation accessibility exacerbated the mismatch in agricultural space.The interaction effects of capital investment and technology innovation with other factors have the most intense impact on the mismatch in urban space.The internal factor for cultivated area interacts with other external factors to drastically affect ecological spatial mismatch.

Spatial-temporal change in urban agricultural land use efficiency from the perspective of agricultural multi-functionality： A case study of the Xi＇an metropolitan zone

The excessive expansion of urbanized areas has resulted in haphazard land utili- zation, immoderate consumption of superior agricultural land and water resources, significant fragmentation of agricultural landscape, and gradual deterioration of the agro-ecological en- vironment. Combined, these factors cause poor land use efficiency. Under these circum- stances, comprehensively assessing land use efficiency for urban agriculture is a key issue in land use research. Currently, evaluation methods for agricultural land use efficiency narrowly concentrate on aspects of economic input and output. However, urban agro-ecosystems can provide diverse economic, social, and ecological services and functions. In particular, the social and ecological services and functions originating from agricultural land, which have a higher value than economic services, play a significant role in ensuring regional social, eco- logical, and environmental security. However, recent research has rarely taken these benefits into consideration. Therefore, land use value has been greatly underestimated, which has resulted in mishandled and poor land use policies. In this study, we apply Landsat imagery and social and economic statistical data for the Xi＇an metropolitan zone （XMZ） to investigate agricultural multi-functionality. We develop an evaluation framework for urban agricultural land use efficiency and identify agro-ecosystem services and functions as important outputs from agricultural land. The land use efficiency of urban agriculture is then evaluated using ecosystem services models, providing a mechanism for assessing spatial-temporal changes in land use efficiency in the XMZ from 1999 to 2015. Four important conclusions are reached from this analysis. First, the rapid urbanization and agricultural transformation from traditional cereal cultivation to modern urban agriculture has resulted in steadily increasing costs, out- puts, and land use efficiency of urban agriculture. The total output value increased 41% and land use efficiency per hectare increased by 33.13% on average. Second, the spatial patterns of comprehensive output and land use efficiency were dominated by economic outputs from agricultural land. Areas near cities, which are dominated by orchard and arable land, provide more economic functions. These areas support and regulate services due to the transforma- tion from extensive cereal production to intensive modern urban agriculture; therefore, they have higher output value and land use efficiency. In contrast, areas distant from cities, towns, and high traffic roads, namely, remote rural areas, provide more support and regulating ser- vices, but have relatively lower economic function due to inaccessibility tO urban markets and slow agricultural transformation. Therefore, these areas have lower output value and land use efficiency. The spatial change in agricultural output and land use efficiency in urban areas is strongly dependent on the degree of urbanization and agricultural transformation. Third, the total output value and land use efficiency of urban agriculture measured with our approach are much higher than evaluations using traditional methods. However, the spatial patterns measured using the two approaches are in agreement. The evaluation framework integrates ecological services and economic and social functions into a comprehensive output from agricultural land. This approach is more methodical and accurate for evaluating the compre- hensive efficiency of land use based on quantities and spatial scale because they are at the pixel scale. Finally, the evaluation results have important implications for enhancing current agricultural subsidies and even implementing ecological payment policies in China. Most importantly, they can be directly applied to agricultural transformation regulations, decision-making, and guidance for rational land utilization.

Spatio-temporal analysis of urbanization and land and water resources efficiency of oasis cities in Tarim River Basin

This paper examines the spatial pattern of land and water resources as well as urbanization and their interactions in the Tarim River Basin, Xinjiang, China. In order to do so, we extract the data associated with efficiency of land and water resources and urbanization for the years of 1995, 2000, 2005 and 2008. Specifically the paper investigates the extent to which agglomeration of population and economic activities varies geographically and inter- plays with spatial pattern of resources efficiency through computation of Global Moran＇s I index, Getis-Ord Gi＊ index and a coordinated development model. The method used provides clear evidence that urbanization, land and water resources efficiency have shown uneven spatial pattern due to oasis distribution, climate, and initial phase of urban development. Some conclusions can be drawn as follows. （1） Agglomeration and dispersion of urbanization are not consistent with those of land and water resources efficiency. （2） Evolution of the hot and cold spots of urbanization, and land and water resources efficiency, in different trajecto- ries, indicate that there are no significant interactions between them. （3） The evidence that numbers of hot and cold spots of the three factors present varying structures reveals the dominance of unequal urban development in the study area. （4） Significant differences are also found between sub-river basins in terms of the three factors, which is a reflection of the complex physical geography of the area. （5） The degree of coordinated development of cities in the Tarim River Basin is generally low in part as a reflection of difference in spatial patterns of the three factors. It is also shown that the pattern of the degree of coordinated development is relatively stable compared with evolution of hot and cold spots of the three factors.

Evolution Characteristics of Urban Land Use Efficiency under Environmental Constraints in China

In the context of high-quality economic development and coordinated regional development,this paper measures the urban land use efficiency of 275 prefecture-level cities in China from 2003 to 2016,taking into account the unexpected output(environmental pollution),and explores the temporal and spatial evolution of urban land use efficiency through kernel density estimation and spatial autocorrelation analysis.The results show that:(1)From 2003 to 2016,China’s urban land use efficiency showed an overall fluctuating growth,but it remained at a low level.The mean value of urban land use efficiency has been gradually decreasing in east,west and central regions.(2)In the whole country and the eastern,central and western regions,the regional differences have been increasing,and the efficiency values of the whole country and the east have become polarized.(3)Urban land use efficiency shows a weak spatial positive correlation,but the degree of spatial agglomeration is increasing.High-high agglomeration areas are mostly distributed in the southeastern coastal areas,and extend into the central region,while most of the high-low polarized areas are the capital cities of the central and western regions.The low-high depressed areas are scattered around the high-value accumulation areas,some of which have turned into high-high agglomeration areas during the study period,while the low-low homogeneous areas are mainly distributed in the central,western and northeastern regions.Therefore,it is proposed that strengthening the utilization of urban stock land,strengthening the regional cooperation mechanism,and formulating policies which improve the efficiency of land use are effective ways to promote the intensive and economical use of urban land,as well as regional coordinated development.

The Ecological Effects of Young Elm Trees Belt-Pumpkin Strip Intercropping System at the Agro-Pastoral Ecotone in Northern China

Young elm trees belt-pumpkin strip intercropping was studied to solve the actual problem of resource losses in the large barren area resulted from reconverting cultivated land into forest in the agro-pastoral ecotone in northern China. The final objective was to realize effective utilization of the barren land with both ecological improvement and economic development. Field experiments were conducted together with laboratory analysis. The results indicated that the soil moisture level was remarkably increased in young elm trees belt-pumpkin strip intereropping because the pumpkin vines covered the gap between pumpkin planting-furrow and elm trees belt. The water use efficiency of the intercropping system was increased by 23.7-163.3% as compared with the single cropping. Elm trees belt-pumpkin strip intercropping changed the sequential succession trend of the grasses growing in the gap of the pumpkin planting-furrow. The annual grasses become the dominant vegetation. The nutritive value as fodder and yield of the annual grasses were also increased remarkably. The biomass of pumpkin, elm trees and grasses under intercropping increased by 24.4, 28.4 and 144.4%, respectively, as compared with those under single cropping. The land use efficiency was increased by 132%. It was also indicated that the soil erosion from the intercropping land was not increased due to pumpkin plantation. The differences in the soil erosion among intercropped area, elm trees belt and pumpkin strip with single cropping were not remarkable. Therefore, it was concluded that young elm trees belt-pumpkin strip intercropping is an effective way to utilize the barren land between the young elm trees belt and realize synergistic enhancement of ecological benefit and economic profit.

Exploring complex urban growth and land use efficiency in China's developed regions:implications for territorial spatial planning

Developed regions in China have experienced rapid urban expansion and have consequently induced a series of challenging environmental issues since its economic reform and opening-up.Taking Zhejiang as a case study area,the present paper explores the complex types of urban growth over the last four decades as well as land use efficiency.Moreover,it discusses the implications of the aforementioned on China national territorial spatial planning(TSP).The acquired results have shown that:1)urban expansion has slowed down,exhibiting a three-stage trend of"slight increase(1980-1990)—dramatic growth(1990-2010)—slow growth(after 2010)";2)the complex types of urban growth reveal that the urban diffusion has been gradually controlled and the urban form tends to be more condensed;and 3)the mean values for pure technical efficiency(PTE)and scale efficiency(SE)of urban land use are 0.83 and 0.95 respectively,indicating PTE as the main factor restricting the improvement of urban land use.Based on these results,some beneficial policy implications and suggestions for TSP are provided.First,it is suggested that"Inventory Planning"will be the main direction of TSP other than"Incremental Planning".Secondly,we should pay more attention to the protection of cultivated land and ecological resources.Lastly,TSP should guide the economic growth away from simply relying on resource inputs and steer it toward technology and capital investment.

Driving Mechanism of Urban Space Expansion in Luoyang, China

Urban space expansion is the result of the interaction between internal and external forces of the urban. Based on the remote sensing image data of 1990, 2000, 2010, and 2020, and the social and economic development data, this paper analyzes the driving mechanism of the Luoyang space expansion characteristics and its correlation characteristics. By using urban land use efficiency index, urban expansion elastic index;urban allometric growth index, and grey correlation analysis in 4 times sections and 3 periods. The research results show that the urban space expansion of Luoyang mainly comes from the needs and support of economic development, the coordination between urban space expansion and population development is poor, and urban space expansion effectively attracts the inflow of external funds, and the settlement of migrants, drives the development of the tertiary industry, and increases the local revenue.

Land Use and Ecological Civilization: A Collection of Empirical Studies

The goal of ecological civilization construction is to realize the harmonious coexistence of human and nature.Land is the spatial carrier of ecological civilization construction.Land use types or behaviors reflect the level of intensive use of land resources,leading to different ecological environmental effects,thereby affecting the level of regional ecological civilization construction.This issue,"Land Use and Ecological Civilization",discusses the theory and method of land use management in the view of ecological civilization from the aspects of land use efficiency,land use change,land multi-functional trade-off,land ecosystem service and land ecological risk by selecting 14 representative papers,providing practical reference for the formation of the land use mode and behavioral system of ecological civilization.With abundant research levels,this issue covers varied research scales such as village,county and province,various landform types such as plain and hill,and typical land use areas at home and abroad such as East China,Central China,Northwest China,Yangtze River Economic Belt and Japan.Being frontier and practical,the multidisciplinary research methods in this issue include literature research method,fractal theory,qualitative comparative analysis,VAR model,and econometrics,among others.Focusing on the prominent problems in the process of land use,this issue deeply discusses the hot topics such as land ecological efficiency,spatial behavior characteristics,land use structure optimization and ecological risk assessment.This issue not only reviews the current literature on urgent land use issues such as arable land abandonment and land use risk,but also tries to conduct trade-off and synergy analysis on the varied functions of the rural landscape and ecosystem,thus providing a theoretical and empirical basis for solving land use problems from the perspective of ecological civilization.This issue reflects the realistic urgency of guiding land use with the concept of ecological civilization,and provides theoretical guidance and technical support from the aspects of methods and research framework.Finally,this issue proposes five hot topics in the field of land use research from the perspective of ecological civilization in the future,namely,ecological management of land use structure,ecological evolution mechanism of land use process,land ecological use mode,early warning and regulation of land ecological security pattern,ecological management and control of land use behavior.

全球超大城市空间扩张及分形特征

Megacities serve as global centers for economic,cultural,and high-tech industries.The structural features and population agglomerations are typical traits of urbanization,yet little is known about the morphological features and expansion patterns of megacities worldwide.Here we examined the spatiotemporal variations of urban land in megalopolises from 2000 to 2020 using the Urban Expansion Intensity Differentiation Index.The fractal features and expansion patterns of megacities were analyzed using the Area-Radius Multi-dimensional Scaling Model.Urban land use efficiency was then evaluated based on the linear relationship between urban land area and population.We found that Southeast Asia and China were the hotspots of urban expansion in megacities from 2000 to 2020,with urban land areas expanding by 3148.32 km^(2)and 5996.26 km^(2),respectively.The morphological features and expansion patterns of megacities exhibited a growing trend towards intensification and compactness,with the average radial dimension increasing from 1.54 to 1.56.The annual decrease in fractal dimensions indicated the integration of inner urban areas.North America and Europe megacities showed a low urban land use efficiency,with a ratio of urban land area to population ranging from 0.89 to 4.11 in 2020.Conversely,South Asia and Africa megacities exhibited a high urban land use efficiency,with the ratios between 0.23 and 0.87.Our results provide information for promoting efficient urban land utilization and sustainable cities.It is proposed to control the scale of urban expansion and to promote balanced development between inner and outer urban areas for achieving resilient and sustainable urban development.