Rapid urbanization and industrialization with their negative repercussions draw attention to the need for urban sustainability. This research built on the urban systems understanding linked with resource utilization, environmental effects, people-environment interactions, and adaptive management by integrating quantitative modelling of urban metabolism with a qualitative investigation into human responses. A hybrid methodology was applied in a typical industrial city of Jinchang, China, which exemplified a model of how complex urban dynamics link to and inform sustainability transitions. The study found that Jinchang City had taken on an unsustainable trajectory underpinned by continuous growth of material consumption, whereas a potential for sustainability transitions was also observed in decoupled negative material outputs, improved material efficiency, and environment regeneration collectively. The challenges in industrial cities have been framed in terms of development model lock-in, conceptual and institutional constraints, innovation and human capital deficiencies, and governance failure. The research proposed a government-led transformation system that integrates multi-level and multi-perspective transformations and management employing discipline insights to facilitate urban sustainability transitions. This involves governance, economic and technological innovations, social transformations, and implementations, in which urban governance and public engagement are essential elements for adapting to undesirable difficulties and exploring locally appropriate strategies. This research provided a theoretical and empirical basis along with scientific and policy implications, which contributed to the developing interdisciplinary knowledge on the understanding of complex urban systems and provided insights into real-world sustainability solutions.

The sustainable utilization of regional cultivated land systems in the Yangtze River Delta (YRD) region over the past 40 years has been severely impacted by rapid urbanization processes. Improving the eco-efficiency of cultivated land use (ECLU) plays a significant role in achieving the sustainable utilization of farmland and high-quality development of agriculture and rural areas. In this study, the spatial–temporal features and influencing factors of the ECLU in the YRD are investigated by various methods, such as a super-efficient SBM model, hot spot analysis, Dagum Gini coefficient, and panel tobit model. The findings indicate the following: the ECLU showed an overall high level from 2000 to 2020; the ECLU varied significantly over time and space in the YRD. The ECLU presented obvious spatial agglomeration in the YRD: southern regions exhibited a concentration of cold spots, while hot spots were primarily found in the east and north of the YRD. The trend of regional differences in ECLU during the research period fluctuated upwards in the YRD, and the density difference super-variable was the main source of regional differences. Increases in urbanization level and GDP per capita contributed to ECLU enhancement in the YRD, and agricultural intensity levels and agricultural industrial structures played a negative role in ECLU improvement. Finally, we suggest that different regions should adapt to local conditions, scientifically and reasonably allocate cultivated land production resources, and promote the coordinated improvement of ECLU. This study could provide a reference for policymakers to formulate better decisions on cultivated land utilization and management.

Understanding the land use/cover changes associated with agricultural production is essential for food security in increasingly urbanizing areas. Such studies have been widely conducted in different regions of China; yet, its major grain-producing regions (MGPRs) remain less studied. To address this knowledge gap, we conducted analyses of the land use conversion matrix, spatial hot spots, decoupling, and index evaluation from a spatiotemporal perspective, to quantify the MGPRs’ farmland changes and its grain production efficiency and ecological security during 2000–2020. The results showed the following: (1) Farmland in the MGPRs experienced a net decline of 2.54 × 10⁴ km², with significant spatial heterogeneity in the area, extent, and speed of loss/gain. (2) Farmland gain came from mostly forest, grassland, and unused land, with hotspots in northeastern China, while farmland loss increasingly changed to construction lands, with hotspots covering east-central China and in the suburbs surrounding capital cities. (3) Grain production in the MGPRs increased by 1.6 times in the past 20 years, via its strong decoupling from farmland quantity in especially central-eastern China. (4) Land ecological security in the MGPRs was less secure but has been improving with non-homogeneous regional differences, while it demonstrated a spatial pattern of “higher security in the north–south and lower in the middle”. Our findings suggested that China’s MGPRs would continue to lose farmland and China’s food security should require a sustainable decoupling of grain production and farmland quantity while maintaining ecological security. This study has significant policy implications for farmland conservation in China’s MGPRs, as well as highlighting the landscape sustainability opportunities of urbanization-associated farmland loss in densely populated human–environment systems in general.