Effects of land use change on the spatiotemporal variability of soil organic carbon in an urban-rural ecotone of Beijing,China

Understanding the effects of land use changes on the spatiotemporal variation of soil organic carbon （SOC） can provide guidance for low carbon and sustainable agriculture. In this paper, based on the large-scale datasets of soil surveys in 1982 and 2009 for Pinggu District -- an urban-rural ecotone of Beijing, China, the effects of land use and land use changes on both temporal variation and spatial variation of SOC were analyzed. Results showed that from 1982 to 2009 in Pinggu District, the following land use change mainly occurred： Grain cropland converted to orchard or vegetable land, and grassland converted to forestland. The SOC content decreased in region where the land use type changed to grain cropland （e.g., vegetable land to grain cropland decreased by 0.7 g kg-1; orchard to grain cropland decreased by 0.2 g kg-l）. In contrast, the SOC content increased in region where the land use type changed to either orchard （excluding forestland） or forestland （e.g., grain cropland to orchard and forestland increased by 2.7 and 2.4 g kg-1, respectively; grassland to orchard and forestland increased by 4.8 and 4.9 g kg-1, respectively）. The organic carbon accumulation capacity per unit mass of the soil increased in the following order： grain cropland soil〈vegetable land/grassland soil〈orchard soil〈forestland soil. Therefore, to both secure supply of agricultural products and develop low carbon agriculture in a modern city, orchard has proven to be a good choice for land using.

Soil quality and sustainable land use in urban-rural marginal area: a case study of Kaifeng

By using the basic theories of physical geography, land resources and ecology, this article analyzes the soil quality of the rural-urban marginal area in Kaifeng. Computer techniques, based on soil samples analysis, are used to study soil quality changes in the Kaifeng’s rural-urban marginal area. While focusing on nutrient circle key links of input and output in soil, relying on numerous practical survey data, this article reveals clearly the impact of land use change on soil quality.

Spatiotemporal dynamics of land use/land cover(LULC)changes and its impact on land surface temperature:A case study in New Town Kolkata,eastern India

Rapid urbanization creates complexity,results in dynamic changes in land and environment,and influences the land surface temperature(LST)in fast-developing cities.In this study,we examined the impact of land use/land cover(LULC)changes on LST and determined the intensity of urban heat island(UHI)in New Town Kolkata(a smart city),eastern India,from 1991 to 2021 at 10-a intervals using various series of Landsat multi-spectral and thermal bands.This study used the maximum likelihood algorithm for image classification and other methods like the correlation analysis and hotspot analysis(Getis–Ord Gi^(*) method)to examine the impact of LULC changes on urban thermal environment.This study noticed that the area percentage of built-up land increased rapidly from 21.91%to 45.63%during 1991–2021,with a maximum positive change in built-up land and a maximum negative change in sparse vegetation.The mean temperature significantly increased during the study period(1991–2021),from 16.31℃to 22.48℃in winter,29.18℃to 34.61℃in summer,and 19.18℃to 27.11℃in autumn.The result showed that impervious surfaces contribute to higher LST,whereas vegetation helps decrease it.Poor ecological status has been found in built-up land,and excellent ecological status has been found in vegetation and water body.The hot spot and cold spot areas shifted their locations every decade due to random LULC changes.Even after New Town Kolkata became a smart city,high LST has been observed.Overall,this study indicated that urbanization and changes in LULC patterns can influence the urban thermal environment,and appropriate planning is needed to reduce LST.This study can help policy-makers create sustainable smart cities.

Exploring Smart Growth Boundaries of Urban Agglomeration with Land Use Spatial Optimization:A Case Study of Changsha-Zhuzhou-Xiangtan City Group,China

Urban agglomeration is the main spatial organization mode used by the Chinese government to promote the policy of new urbanization strategy.Hence,a better understanding of the urban growth boundary(UGB)has profound theoretical and practical significance regarding sustainable urban development.This study devised a raster-based land use spatial optimization(LUSO)framework,and utilized ant colony optimization(ACO)algorithm to delimit the smart growth boundaries of the Changsha-Zhuzhou-Xiangtan city group(CZTCG)in China.The aim of this study is to design a LUSO model to explore an optimal pattern of urban agglomeration for sustainable growth.Multi growth scenario including a single development center,multipolar development and balanced development patterns are generated by the LUSO model for the year of 2050,and the optimum spatial pattern is chosen based on objectives comparison and the present stage of economic and social development in CZTCG.The main results are listed as the following.1)It is feasible to identify the growth boundaries of the urban agglomeration using the land use spatial optimization model,and the optimal form of the spatial pattern can be defined.2)With the growth trend of the urban agglomeration gradually spreads from a single center to multi-centers and even small towns,the total optimization target performance gradually increases,which means that the traditional pie-shaped development does not meet the maximum comprehensive benefit of the city group.3)Subject to the regional social and economic development stage,absolute fair development or simply developing the central city is not conducive to promoting the coordinated development of the urban agglomeration.Gradient equalization and gradual advancement are the best choice for UGB delineation of urban agglomeration.The findings of this study would be useful to identify the UGB in CZTCG for more sustainable urban development in the future.

RS and GIS-based Analysis of Landscape Pattern Changes in Urban-rural Ecotone:A Case Study of Daiyue District,Tai' an City,China

Based on RS data of Daiyue District,Tai'an City in 2000,2005 and 2010,changes of land use types in urban-rural ecotone of Tai'an City from 2000 to 2010 were analyzed.Ecological theories,ArcGIS techniques and landscape structure analysis software Fragstats were applied to select relevant landscape pattern indexes and analyze changes of landscape structure,and compare changes in two durations(2000-2005,2005-2010).The results showed that area of natural landscapes in the study area declined from 2000 to 2010,construction land expanded,land use types were mainly transferred from natural landscapes to man-made landscapes.In terms of landscape level,number of patches(NP),patch density(PD),patch shape index(SHAPE),Shannon's diversity index(SHDI) and Shannon's evenness index(SHEI) increased,the largest patch index(LPI) declined.In terms of type level,arable land were influenced by the most human interventions,large-scale patches turned fragmented,and landscape dominance degraded;woodland landscapes were concentrated in mountainous areas,waterscape indexes showed slight changes.Dominance of regional dominant landscape types degraded,landscape fragmentation and landscape heterogeneity increased,and landscape stability declined.

Impacts of Transportation Arteries on Land Use Patterns in Urbanrural Fringe: A Comparative Gradient Analysis of Qixia District, Nanjing City, China

Integrated transportation and land use studies are of major interest to planners because they consider the interaction between transportation development and land use change. Quantifying the impact of transport infrastructure on land use change is necessary for evaluating the role of transportation development in the process of land use and land cover change in the urban-rural fringe. Taking Qixia District of Nanjing City, Jiangsu Province, China as a typical urban-rural fringe area, this paper analyzes the patterns and charac- teristics of land use change along three major transportation arteries using land use data from 2000 and 2008. We examine the spatial differentiation and gradient of land use pattern around railway, expressway, and highway corridors to investigate whether land use change in the urban-rural fringe is related to distance from transportation arteries and to clarify the varying impacts of different forms of transport infrastructure on land use patterns. We find that construction land generally tends to be located close to major transportation arteries, and that railways have the most obvious influence on land use change in the urban-rural fringe, while the impact of expressways was not significant. We conclude that there exists a causal relationship between the presence of transportation arteries and land use change in the urban-rural fringe, but this relationship varies across different types of linear transnort infrastrncnlre.

Expansion of Urban Space and Land Use Control in the Process of Urbanization: an Overview

Urban expansion brought by the rapid progress of urbanization has caused many problems in China. It is a significant issue to evaluate the extent of urban expansion and to make appropriate controls over the sprawl of urban areas. With a comparative study of international experiences, this article analyzed the mechanism and consequences of urban expansion, reviewed the typical planning and financial policies adopted by other countries for controlling urban sprawl, and discussed the suitable densities of urban areas. The analysis results suggested that Chinese cities have no better choice but compact urban forms. To achieve the goal of compact development, intensive use of public transportation and high proportion of collective houses should be encouraged, and 60–100 m2 per capita is recommended as the reasonable range of urban density in large cities.

Land Use Land Cover Dynamics and Farmland Intensity Analysis at Ouahigouya Municipality of Burkina Faso,West Africa

Sahel zone has been reported as one of the most vulnerable regions to climate change, so serious attention must be paid to this zone by researchers and development actors who are interested in environmental-human dynamics and interactions. The aim of this study was to bring more insight into the impact of actions aiming at reducing land degradation, regreening the Sahel, stopping population migration and reducing the pressure on land in the Sahelian zone. The study focused on farmland dynamic in Ouahigouya municipality based on remote sensing data from 1986 to 2016 using intensity analysis. The annual time interval change was 0.77% and 2.46% for 1986-2001 and 2001-2016, respectively. Farmlands gained from mixt vegetation, water bodies and from bar lands. Mixed vegetation and water bodies were both active during both intervals while the other land use such as woodland and bar land were dormant. Combining land use land cover analysis and intensity analysis was found to be effective for assessing the differentiated impact of the various land restoration actions.

Land use transition and rural spatial governance: Mechanism, framework and perspectives

The pattern for utilization of rural space is closely related to rural transformationdevelopment (RTD). The problem of rural space utilization is an important manifestation of theuncoordinated relationship between land use patterns and rural development status during atransformation period. Considering the rural space utilization issue, this article seeks to analyzethe interaction mechanisms between land use transition (LUT) and rural spatial governanceand then build a rural spatial governance analysis framework based on LUT. Also, thepaper explores the internal relationship between rural spatial governance and rural vitalizationand discusses the research prospective of the interaction. The study found that: (1) Ruralspace utilization has systemic problems such as limited development space, ill-defined ownershipand poor organization, which have become important obstacles for rural development.(2) The uncoordinated relationship between LUT and RTD is an important reason for the dilemmasurrounding rural space utilization. (3) The LUT provides a basis for determining thetiming of rural spatial governance, specifying spatial governance objectives, and clarifyingrural spatial governance methods. (4) The construction of a comprehensive analysis frameworkof “matter-ownership-organization” of rural space based on the LUT has created conditionsfor the orderly promotion of rural spatial governance. (5) Rural spatial governance whichfacilitates the integration of urban-rural development is an important foundation for rural vitalization.(6) Interaction analysis of LUT, RTD and rural spatial governance is conducive tofacilitating research on the operational mechanism of rural regional systems and to expandingthe research field of rural geography.

Land consolidation： An indispensable way of spatial restructuring in rural China

The implementation of new type industrialization and urbanization and agricultural modernization strategies lacks of a major hand grip and spatial supporting platform, due to long-term existed ＂dual-track＂ structure of rural-urban development in China as well as un- stable rural development institution and mechanism. It is necessary to restructure rural pro- duction, living and ecological space by carrying out land consolidation, so as to establish a new platform for building new countryside and realizing urban-rural integration development in China. This paper develops the concept and connotation of rural spatial restructuring. Basing on the effects analysis of industrialization and urbanization on rural production, living and ecological space, the mechanism of pushing forward rural spatial restructuring by carry- ing out land consolidation is probed. A conceptualization of the models of rural production, living and ecological spatial restructuring is analyzed combining with agricultural land con- solidation, hollowed villages consolidation and industrial and mining land consolidation. Fi- nally, the author argues that a ＂bottom-up＂ restructuring strategy accompanied by a few ＂top-down＂ elements is helpful for smoothly pushing forward rural spatial restructuring in China. In addition, the optimization and restructuring of rural production, living and ecological space will rely on the innovations of regional engineering technology, policy and mechanism, and mode of rural land consolidation, and more attentions should be paid to rural space, the foundation base and platform for realizing urban-rural integration development.

Occurrence, spatial distribution and ecological risks of antibiotics in soil in urban agglomeration

Antibiotics in soil environment are regarded as emerging pollutants and have introduced increasing risks to soil ecosystem and human health in rapid urbanization areas. Identifying the occurrence and spatial variability of antibiotics in soils is an urgent issue in sustaining soil security. In this study, antibiotics in soils were investigated and analyzed in BeijingTianjin-Hebei urban agglomeration. The occurrence, spatial distribution, and related affecting factors of antibiotics in soils were identified and ecological risks of antibiotics in soil environment were assessed. Results showed that(1) The mean concentration of soil antibiotics in Beijing-Tianjin-Hebei urban agglomeration was 21.79 μg/kg. Land use substantially affected the occurrence and concentration of antibiotics in soils. Concentrations of antibiotics in cropland and orchard soils were 2-3 times higher than the other land use types.(2)The concentrations of antibiotics in soils in Beijing-Tianjin-Hebei urban agglomeration presented a spatial pattern of high values in southeast, and low values in northwest. Spatial variability of antibiotics in soils was closely related to the application of organic fertilizer and wastewater irrigation as well as topographical features. Furthermore, soil properties and land management policy had substantial influences on soil antibiotics, and soil heavy metals may aggravate the accumulation of antibiotics in soils.(3) Ecological risks assessment of antibiotics in soils demonstrated that erythromycin(ERY), sulfamethoxazole(SMX), and doxycycline(DOX) may introduce high risks to soil ecosystem health, and more attention should be paid to the areas with intensive human activities that had potential high risk to soil ecosystem health. This study suggests that scientific land and soil management should be considered to prevent soil antibiotic pollution and sustain soil security in urban agglomeration.

“Three-Plan Integration”: Exploring the Order and Regulation Capacity of Spatial Planning

China's spatial planning system has a tradition of prioritizing vertical control over horizontal coordination, which leads to conflicts among various plans for one area. This has brought many problems to the spatial management of Chinese cities. Since socio-economic development plan, urban-rural plan, and land use plan are the three major elements of China's spatial planning system, conflicts among them can be taken as an intensified case of the system's problems, and the practice of three-plan integration should focus on bridging the gaps and solving conflicts among them, so as to eventually eliminate predicaments to China's spatial planning. Currently, due to influences of the actual law and governance systems, threeplan integration is largely a sort of government-led planning coordination dedicated to urban-rural spatial development. In the context of China's constantly deepened political and economic system reforms, three-plan integration, together with the extended multi-plan integration, will surely play an important role in the construction and exploration of China's spatial planning system.