Driven by urbanization and industrialization, arable land in hilly and mountainous regions of China is gradually becoming marginalized, with the extent of arable land abandonment rapidly expanding from poor-quality sloping arable land to high-quality terraces. The abandonment of large-scale terraces will lead to a series of socio-economic and ecological effects. A national sample survey was used to investigate the extent and spatial distribution of terrace abandonment in China, and a total of 560 valid village questionnaires from 329 counties were collected in the mountainous areas of China. The main findings are as follows: (1) The phenomenon of terrace abandonment was widespread throughout the country, with 54% of the total surveyed villages exhibiting terrace abandonment, and the area of abandoned terraces accounting for 9.79% of the total. (2) The degree of terrace abandonment is high in the south and low in the north. The most serious region with abandonment was the hilly and mountainous areas in the south, especially in the middle and lower Yangtze River region. (3) The main driving factors of terrace abandonment were rural labor migration, agricultural mechanization level, irrigation conditions, and transportation conditions for cultivation. Targeted measures should be taken based on the specific conditions of each area to alleviate terrace abandonment. Measures such as improving terrace mechanization are universally applicable. Specifically, low-quality terraces can be withdrawn orderly, and for high-quality terraces, multiple measures are needed to consolidate agricultural production, such as adjusting the planting structure, strengthening agricultural infrastructure construction, and encouraging the transfer of land-use rights as well as large-scale operation.
Rust belt cities are largely threatened by a waste of urban space at their core; however, in developing countries where land resources are widely used as instruments for macroeconomic stabilization, urban periphery is also at risk of being underutilized due to land hoarding. Such geographic differences entail new knowledge about how, where, and why underutilized lands are regenerated in the city. Furthermore, rapid urban growth imposes development disparity and mixed underutilization issues on cities in developing countries; therefore, how the geo-information obtained by the regeneration of different underutilized lands differs will be valuable for urban planners and policymakers to make prudent trade-offs. To fill these gaps, we conducted a sequential investigation into the regeneration of underutilized lands in a representative rust belt city - Changchun City in Northeast China, in an attempt to measure the regeneration pattern and analyze the underlying determinants using the Classification and Regression Trees analysis. The results indicated that, of all underutilized lands, increments of vacant lot and remnant cultivated land continued to plague the expanding urban periphery during 2016-2019. In a way, reduced underutilized lands alleviated land use conflicts at the city core. Nearly 23% of the underutilized areas had been regenerated, dominated by realty development, with most converted to residential lands, ecological lands and industrial lands. On the contrary, conversion to transportation lands and parking lots seemed to avoid the rapidly expanding sites. The regeneration rates in a certain area can be increased by a multitude of factors, including denser, simply structured land underutilization, abundant ecosystem services nearby and accessibility to public infrastructures. Site conditions such as residential density and accessibility may have fueled the regeneration associated with residential purposes, while regeneration of industrial development was closely associated with the underutilization density and parcel regularity. This research provides an empirical paradigm for delivering regeneration geo-information across different underutilized lands, particularly for rust belt cities that are caught between a shrinking core and speculative periphery.
The current suitability evaluation methods for land resources human activity in China suffer from theoretical deficiencies related to fundamental data accuracy, elevation and slope classification, and suitability class judgment. Empirical application of these methods is also hindered by excessive evaluation indicators, data acquisition difficulties, and limited applicability to high altitude regions. To address these issues, this paper proposes a technical evaluation framework for the Qinghai-Tibet Plateau (QTP) that employs selected key parameters varying with elevation and slope to establish grid-scale evaluation models for construction land suitability (CLS) and arable land suitability (ALS). A generalized algorithm is then proposed for key parameters such as air density, air temperature, slope suitability for construction, and soil erosion resistance of sloping arable land. Empirical research is conducted using Milin County in southeast Tibet as a case study, with interval measurements of 100 m in elevation and 1° in slope. The evaluation model is tested using grid accuracies of 30 m, 50 m, 100 m, 250 m, 500 m, and 1000 m. The results reveal that: Firstly, the CLS and ALS can be categorized into five classes: highly suitable, suitable, moderately suitable, marginally suitable, and unsuitable, with varying area ratios under different grid accuracies. Secondly, existing construction lands in Milin County are mainly distributed in suitable, highly suitable, and moderately suitable CLS classes, accounting for over 94% of the total area studied under different grid accuracies. While arable land is mainly distributed in suitable, highly suitable, and moderately suitable ALS classes, accounting for over 96%. Thirdly, the empirical research in Milin County indicates that the evaluation method, quantitative model, and parameters algorithm for evaluating human activity suitability of land resources on the QTP are feasible and applicable, with a recommended grid accuracy within 100 m and a maximum of 250 m. Fourthly, the paper establishes a correspondence between land suitability (including construction land and arable land) and topographic factors (elevation and slope) that can be applied to the QTP. Finally, some professional defects in the evaluation methods of available land resources in Major Function Zoning and “Double Evaluations” of Territorial Spatial Planning in China when applied to the QTP are identified.
Rapid urbanization has occurred in arid/semiarid China, threatening the sustainability of fragile dryland ecosystems; however, our knowledge of natural environmental constraints on multiscale urban lands in this region is still lacking. To solve this issue, this study retrieved 15-m multiscale urban lands. Results indicated that urban area increased by 68% during 2000-2018, and one-third of the increase was contributed by only three large cities. The coverage of impervious surface area (ISA) and vegetated area (VA) increased by 16.6% and 1.38%, respectively. Such land-cover change may be helpful in suppressing wind erosion and sand storms. We also found that the newly urban lands had relatively lower ISA and higher VA than the old urban lands, indicating an improved human settlement environment. Strong environmental constraints on urban expansion were identified, with cities in oasis urban environments (OUEs) that had water supply expanding 150% faster than cities in desert urban environments (DUEs). Urban development was also constrained by terrain, with 73% of the ISA expansion occurring in relatively flat areas. Overall, the aggregated pattern of urbanization and the increase in ISA and VA in the newly urbanized lands have improved water-use efficiency and ecological services and benefited desert ecosystem protection in arid/semiarid China.
The agglomeration of the rural e-commerce industry represented by Taobao villages has reshaped the existing urban and rural spatial organization and proposed a new urbanization model. This study identified the spatiotemporal characteristics of Taobao villages in Quanzhou city and built panel regression models to examine the impact of these villages on urbanization level, which is measured via nighttime light (NTL). The results show that (1) while the number of Taobao villages in Quanzhou city has increased rapidly, it has also experienced sporadic growth and monocentric agglomeration, finally forming a polycentric agglomeration pattern; (2) Taobao villages display a significant near-city tendency, and the urbanization level of towns with Taobao villages is higher than that of towns without Taobao villages; (3) the panel regression model highlights that Taobao villages have a significant positive impact on urbanization level. Taobao villages near the city exhibit a greater effect; meanwhile, those that are far away from the city cannot improve their urbanization level unless they reach a considerable degree of agglomeration. Rural e-commerce will become an important direction for the transformation of urban fringe areas, which provides a certain reference for the development of new urbanization in China.
Under the wave of globalization, some cities in China, especially the so-called “megacities” are entering or have already entered the stage of post-suburbanization. The study places Shanghai suburbs in the post-suburbanization landscape and takes Qingpu New Town as an example to systematically analyze the development and formation mechanism of post-suburbanization spaces. This study reveals the features of the post-suburbanization in China as follows. Firstly, In China, post-suburbanization is achieved based on industrialization as well as on the promotion of urbanization. Although urbanization has strengthened other functions of suburban spaces aside from living and production, the production attributes of suburbs remain stable. Secondly, post-suburbanization space with the new town as the development model is an important path for a new round of suburban space growth, it has expanded the space for capital accumulation in metropolitan areas, thus promoting the possibility of reorganizing economic activities within metropolitan areas. At the same time, it focuses on the integration of industries and cities, and the simultaneous development of urbanization and industrialization. In turn, this promotes the accumulation of capital centered on the urban environment and manufacturing production. Furthermore, China’s special institutional circumstance enables its government to organize various actors to form a growth alliance, which will act together in the production of post-suburbanization space.
The number of urban vitality assessment studies is rising continuously, owing to the emergence of geographic data. The current literature focuses primarily on evaluation, rather than implementation, of urban vitality. Hence, a scoping review and research agenda are needed for urban vitality research to be more practical. This study aims to fill the research gap by exploring the content and methods of vitality assessment that can make urban vitality research more compatible with policy, planning, and design practice. We chose the neighborhood scale, which is the most practical initiative unit for vitality enhancement. We discovered that the gaps between the current research and practice primarily lie in the diversity of research subjects, the authenticity and comprehensiveness of vitality measurement, and the multi-domain of impact factor analysis. On this basis, we classified the following expandable aspects: (1) multi-type, multi-dimensional, multi-temporal, and implementation-adaptive vitality evaluation; (2) methods reflecting high-quality social interactions and the perceptions of vulnerable groups; (3) how design and urban management impacts vitality; and (4) the synergistic effects of multiple indicators on vitality. Overall, the research content and methodology presented in this paper can help neighborhood-scale vitality assessment to provide more meaningful insights for policy makers and practitioners.
As a new mode for Chinese overseas investment and a growth pole for industrialization and urbanization of the host countries, the overseas economic and trade cooperation zone (OETCZ) or overseas free economic zone (OFEZ) of China plays an important role under the Belt and Road Initiative. With the rising attention on OETCZ, studies regarding OETCZ have also increased. However, there is a lack of studies reviewing this topic’s progress, challenges and future directions. This paper employs a systematic review to examine the literature on the OETCZ along the Belt and Road, based on domestic and overseas studies. The results show that domestic studies account for a large proportion of the collected literature, compared to overseas studies. Interdisciplinary research focus includes inductive case studies from a classification perspective, deductive studies based on cultural and institutional perspectives, trade network and bilateral trade relations based on the perspectives of international trade and regional economy, spatial planning studies from urban planning perspective, and overseas comments and earlier studies on Japan’s and Singapore’s overseas parks from the geopolitical and international political perspectives. Despite diverse research contents and dramatic progress, limitations exist in current OETCZ-related studies, including a lack of exploration of the mechanism, questions and concerns from overseas scholars, sustainable development and other problems. Future studies should broaden and deepen research insights, including the “overseas free economic zones (OFEZ)” as a general designation to cover all other types of OETCZs, studies on the primary conditions of host countries, exploration of the theoretical issues behind China’s OETCZ, comparative study of OETCZs such as management structures, profit models, environmental standards and legal systems as well as popular issues questioned internationally.
Under the framework of ecological civilisation, the formulation of territorial spatial planning (TSP) and improvement of spatial governance systems are of great practical significance. Since the founding of the People’s Republic of China, land-use planning (LUP) has experienced profound changes, and tremendous research efforts have been made in that field. However, systematic studies on LUP history are scarce. To bridge the existing gap, this study traced back to the emergence of LUP, described its practice stages, and analysed the evolution of its classification system and methods. Further, the three rounds of general LUP practice and the current TSP over the past 40 years of the reform and opening-up have been discussed. The evolution of LUP was found to be closely related to economic development and could be broadly divided into four stages. The development of land-use classification in China has been slow and can be divided into five stages according to the evolution of the land classification system and important historical events. The development of LUP methods can be divided into two stages, before and after 1978. Since the economic reform, China has successively conducted three rounds of general LUP under different institutional and policy backgrounds. Future development should aim to innovate the theories and methods of TSP with Chinese characteristics and promote the study of village planning and the construction of TSP systems to achieve rural revitalisation and ecological civilisation.
Soil particle-size fractions (PSFs), including three components of sand, silt, and clay, are very improtant for the simulation of land-surface process and the evaluation of ecosystem services. Accurate spatial prediction of soil PSFs can help better understand the simulation processes of these models. Because soil PSFs are compositional data, there are some special demands such as the constant sum (1 or 100%) in the interpolation process. In addition, the performance of spatial prediction methods can mostly affect the accuracy of the spatial distributions. Here, we proposed a framework for the spatial prediction of soil PSFs. It included log-ratio transformation methods of soil PSFs (additive log-ratio, centered log-ratio, symmetry log-ratio, and isometric log-ratio methods), interpolation methods (geostatistical methods, regression models, and machine learning models), validation methods (probability sampling, data splitting, and cross-validation) and indices of accuracy assessments in soil PSF interpolation and soil texture classification (rank correlation coefficient, mean error, root mean square error, mean absolute error, coefficient of determination, Aitchison distance, standardized residual sum of squares, overall accuracy, Kappa coefficient, and Precision-Recall curve) and uncertainty analysis indices (prediction and confidence intervals, standard deviation, and confusion index). Moreover, we summarized several paths on improving the accuracy of soil PSF interpolation, such as improving data distribution through effective data transformation, choosing appropriate prediction methods according to the data distribution, combining auxiliary variables to improve mapping accuracy and distribution rationality, improving interpolation accuracy using hybrid models, and developing multi-component joint models. In the future, we should pay more attention to the principles and mechanisms of data transformation, joint simulation models and high accuracy surface modeling methods for multi-components, as well as the combination of soil particle size curves with stochastic simulations. We proposed a clear framework for improving the performance of the prediction methods for soil PSFs, which can be referenced by other researchers in digital soil sciences.
