Farmland protection is important for ensuring national food security and promoting sustainable socioeconomic development. China has a far lower amount of farmland area per capita than the global average. To improve farmland productivity, the Chinese government has implemented a basic farmland protection system (BFPS). A comprehensive and systematic analysis of the evolution mechanism of the BFPS, the failures of the BFPS and the key measures of the modern BFPS reform is lacking in the current literature. Based on a systematic review of the history of China’s BFPS, this study first summarizes the evolutionary mechanism of the BFPS, then analyzes the current conflicts faced by the BFPS on this basis, proposes several main breakthrough strategies for improving the BFPS and finally provides key ideas for further strengthening the development of the BFPS in the future. The results of this study show that China’s BFPS has gone through three development stages since 1963 and that there are differences in the main factors hindering the improvement in basic farmland productivity in the different stages. Correspondingly, the systems adopted to meet the demands for basic farmland protection are also different. The evolution of the BFPS is similar to a “scale” that constantly seeks balance between “system demand” and “system supply”. In the present stage, the main conflicts faced by China’s BFPS are between basic farmland quality and requirements for supplementary delimitation and production patterns; between basic farmland quantity, urban development and food security; and between basic farmland-use regulation and modern agriculture and the market economy. The Chinese government should further optimize the BFPS through improving the delimitation system, establishing a classified protection system and strengthening the basic farmland protection compensation system. To accelerate the establishment of a territorial spatial planning system in the future, the BFPS should also be fully integrated with the concept of an ecological civilization, be applied to resolve the contradiction between development and protection and be used to help improve the land-space-utilization control system, thus creating a unified development guide for national land.

Under the context of rapid urbanization, how to use construction land resources under the dual pressure of socioeconomic growth and cultivated land protection is critical to resource utilization and sustainable development. Thus, it is of great theoretical and practical significance to study the relationship between socioeconomic change and construction land expansion. Based on decoupling theory, this study constructed a two-dimensional model to analyze the population-construction land and economy (non-agricultural GDP)-construction land decoupling status and characteristics in Hebei Province at the county level. Then, a decoupling-based construction land-use zoning model was built to explore construction land saving and intensive utilization strategies in different construction land-use zones. The results show that (1) the construction land area, population and non-agricultural GDP in Hebei Province increased in the study period, but there were spatial differences in the hot areas of growth. (2) In the population-construction land dimension, the growth of the population and construction land in Hebei Province was generally in an uncoordinated state. According to the results of the calculation, the samples of counties whose relationships between population and construction land were uncoordinated accounted for 75.76% of all counties, and 68.94% of all counties demonstrated weak decoupling. (3) In the economy-construction land dimension, 89.39% of all counties in Hebei Province had coordinated relationships between economy and construction land change. The expansion negative decoupling was the main decoupling state in Hebei Province in this dimension. (4) On the basis of two-dimensional decoupling type results, the construction land-use in Hebei was divided into four zones: “Population–economy dual coordinated”, “population unilateral coordinated”, “economy unilateral coordinated” and “population–economy dual uncoordinated”. The results showed that the “economy unilateral coordinated” zone included 68.18% of all counties. According to the characteristics of different construction land-use zones, this study provided various regulatory and control countermeasures and suggestions to improve the efficiency of construction land-use and to promote sustainable development in Hebei Province.

Deeply integrated vulnerability and its evaluation framework provide a new perspective for the study of socio-ecological systems in metropolitan suburbs. A new vulnerability evaluation system of ‘exposure-sensitivity-adaptability’ based on the socio-ecological system and vulnerability theory was constructed. Meanwhile, drawing on the concept of ‘spatial trap’, the concept of ‘spatial vulnerability trap’ was tried to put forward. The spatial-temporal interaction characteristics were analyzed, the existence of spatial vulnerability trap was tested and the interaction mechanism of vulnerability dynamic evolution was revealed using spatial-temporal exploration analysis method and geographic detector for socio-ecological system vulnerability of 184 administrative villages in Qingpu District from the year 1998 to 2018. The results showed that: (1) During the study period, the socio-ecological systems vulnerability of Qingpu District increased from 0.518 to 0.621, and the vulnerability level increased from low grade to medium grade. The spatial-temporal pattern showed the dynamic characteristics of first increase and then decrease and high in the East and low in the west. (2) The relative length of the socio-ecological systems vulnerability temporal path movement in Qingpu District from 1998 to 2018 showed a trend of gradual decline from the central region to the surrounding area. The mobility curvature of the vulnerability time path was relatively small, showing the spatial pattern of low in the north and high in south, and the cohesion index of the spatial transition of vulnerability is 0.496. The spatial agglomeration structure had relatively high transfer activity and low path locking. (3) No ‘spatial vulnerability absolute trap’ was detected during the study period, yet the ‘spatial vulnerability relative trap’ highlighted in the 11 administrative villages mainly distributed around the administrative boundary in the north and south of the area. (4) Social capital factor, human capital factor, social factor, economic factor, ecological factor and financial capital factor are the main factors influencing the vulnerability change, but the influence of each factor showed fluctuation and type difference. The main interaction types of socio-ecological system vulnerability differentiation in urban suburbs are the cumulative type of internal and external coupling, the type of endogenous capacity constraint and the external environmental stress type. The results of the study are of great theoretical and practical significance to guide the suburban areas to prevent the vulnerability risk, promote regional coordination to reduce vulnerability and sustainable development.

Understanding urban state transitions is critical for sustainability, yet a unified framework to characterize the interactive dynamics of key urban components—green vegetation (GV), impervious surface (ISA), and bare soil (BS)—has been lacking at a national scale. To bridge this gap, we developed a novel framework that moves beyond static mapping to directly quantify the dynamic interactions within the V-I-S nexus. Leveraging over 200,000 Landsat images on Google Earth Engine, we generated the first continuous, annual V-I-S fraction maps for China (1990-2019) using a unified spectral endmember space with change trajectory model to characterize and quantify multi directional urban state transitions. Through our pixel-level trajectory analysis, where we integrated the magnitude, timing, and trend of V-I-S changes into a set of conversion rules to systematically identify five transition archetypes: stable, expansion, intensification, green recovery, and soil exposure. This framework demonstrated superior capability in tracking the complex intra-urban landscape components with high accuracy (i.e., smaller mean squared error of -2.07% to 3.44%) and low uncertainties (i.e., fractional biases less than 0.10), as well as achieving highly accurate historical state transitions mapping (87.29%) at fine-scale feature resolution. Our analysis reveals a national-scale GV loss (-31,109 km²) alongside ISA (+28,294 km²) and BS (+2,814 km²) gains, primarily driven by expansion (46%) and intensification (28%). Crucially, we uncover a pivotal shift from expansive growth to intensification and greening as cities develop. This study provides the first spatially explicit, nationally consistent record of intra-urban dynamics, offering a powerful tool for modeling urban social-ecological systems and guiding targeted governance for sustainable urban futures.