Cultivated land (CL) protection is an overarching strategic concern for stabilizing the agricultural foundation and for achieving the sustainable development of the national economy and society. Faced with the challenges of the dual drives of complex domestic and international situations, China’s CL protection system has coupled the quantity and quality dimensions and focused on a dynamic balancing system and permanent basic farmland (PBF) policy. However, it has had difficulty meeting the objectives of sustainable agricultural development and is undergoing upgrades. Accordingly, the Chinese government has issued a CL protection policy that includes adjusting the planting structure, optimizing the agricultural layout, and adding the three dimensions of quantity, quality, and planting structure, namely “Delimitation of the Grain Production Functional Zone and the Important Agricultural Product Production-Protection Zone” (the “two zones” policy). With regard to the ambiguous understanding of the two zones policy, this study aims to explore the following issues: (1) How was the two zones policy conceived? (2) What mechanism does it use to make up for the deficiencies of the previous policy? (3) How does it integrate the three dimensions of quantity, quality, and planting structure? (4) How to reasonably delimit the two zones. To solve these problems, this paper first reviews the evolution of China’s CL protection policies and explains the incubation process of the two zones policy and its connotation and mechanism. Then, a delineation framework process is proposed and the approaches of executing the two zones policy on a regional scale are discussed. Furthermore, a real delimitation was conducted in Qianguo County to validate the framework. The evidence shows that customizing CL use according to regional resource potential differentiation and forming a CL protection policy with the three dimensions of quantity, quality, and structure are effective in improving the productive potential of CL and promoting the adjustment of the planting structure. Furthermore, the framework and case study findings of the delimitation provide a theoretical reference and practical foundation to translate macro policy into micro management.

Context Current research on urban ecosystem services faces three major challenges: scale gap, disciplinary barriers, and knowledge fragmentation, necessitating a systematic assessment framework to support precise governance decisions. Objectives This study proposes a cascading "Typology-multifunctionality-supply and demand" framework to establish a full-chain research paradigm, enhancing information flow and feedback mechanisms from fundamental understanding to management implementation. Methods A practical case study in Changchun, Northeast China, applied multisource data and interdisciplinary tools to map urban green space (UGS) typologies, assess multifunctionality, and identify supply–demand mismatches. Results UGS ecological functions exhibit higher values at the edges and lower values in the center, contrasting with the spatial distribution of social functions. Significant synergies exist among ecological functions, while weak trade-offs are observed between ecological and social functions, with most UGS being ecology-dominant. The mismatches of supply–demand gradually transition from social to ecological aspects from the inner ring to the outer ring of the city. The multifunctional performance characteristics of different UGS types vary significantly. The "Three-Question Decision Toolkit" (Where-What-Which) enables the optimization of UGS management by tracing decision-making processes back to typological adjustments, integrating spatial prioritization, functional enhancement, and targeted type-specific interventions. Conclusions The cascading framework’s bidirectional coupling mechanism (forward analysis and feedback optimization) provide theoretical and practical tools for precision governance of high-density cities.

In the context of rural revitalization, identifying the functional characteristics of rural homesteads and clarifying the relationship among various functions are important scientific issues for the transformation of homestead utilization. Taking Jilin Province as an example, this paper analyzes the problems existing in rural homestead utilization from the aspects of quantitative characteristics, human–land matching degree, and the current situation of idle homesteads. An evaluation index system is constructed to measure the functional values of homesteads to identify the advantageous functions of homesteads. The results are as follows: (1) in some areas of the Jilin Province, the per capita homestead area is relatively large, with a high vacancy rate, and there is a phenomenon of inefficient use of homesteads, (2) according to the calculation results of the homestead functional index, the overall performance of the four functions of rural homesteads is in the order of living function > security function > production function > asset function, indicating that traditional living function remains predominant in the study area, (3) based on the relationship between the comprehensiveness and coordination of the four functions of homesteads, villages are classified into “moderate optimization area”, “key improvement area”, “collaborative optimization area”, and “potential improvement area”.