Cultivated land is one of the most important resources in modern agriculture. Quality regulation and time-sequence zoning have been also of great significance for the consolidation and construction of cultivated land resources, from the comprehensive perspective of the synergy of multiple subjects in the process of cultivated land use and protection. In this study, Quzhou County, an intensive agricultural region in the North China Plain, was taken as the study area. A diagnostic model of ecological niche obstacle factors was then applied to identify the obstacles to the quality of cultivated land. Combined with the main body, the regulation model was then constructed from the synergistic perspective of the main body and the object. The construction zones of cultivated land quality were divided, according to the spatial distribution. The specific application of the regulation model was explored in the different zones, in order to determine the time sequence of the consolidation. The results showed that: 1) The quality of cultivated land was dominated by the high and medium, which together accounted for 77.42% of the total. The average grade of cultivated land quality was 2.54 between high and medium quality. However the cultivated land quality locally showed a significant positive agglomeration. 2) There were different area characteristics at the different obstacle levels for each indicator of cultivated land quality. The main obstacle factors of cultivated land quality were the soil organic matter, groundwater depth, irrigation guarantee rate, soil cation exchange capacity, total nitrogen, available phosphorus, and soil profile constitution. 3) The roles of the different subjects (such as government, farmers, enterprises, universities, and village collectives) were determined in the different dimensions (such as growth condition, fertility status, production condition, water, and salt condition) from the perspectives of dominant, core, participatory, guiding, and linkage. The main obstacle factors were consolidated to improve the quality of cultivated land as the basic orientation. Then, the overall framework of the regulation model was comprehensively constructed from the aspects of control dimensions, indicators, measures, and subjects. 4) The quality of cultivated land was divided into four remediation sub-zones: priority, key, potential, and general consolidation zoning. The specific application of the regulation model was proposed in different consolidation sub-zones. Meanwhile, a time sequence was established to consolidate cultivated land quality for near-term construction in the priority zone, medium-term construction in the key zone, long-term construction in the potential zone, and long-term construction in the general zone. A regulation model can be expected to identify the time sequences of quality consolidation for the cultivated land at the county scale using the synergistic perspective of multiple subjects. The finding can provide a basic basis for constructing the quality regulation model and time sequences of cultivated land at different scales, such as the municipal and provincial levels.

Cultivated land can greatly contribute to national food security and sustainable agriculture. It is of great significance to determine the zones of arable land quality in recent years. The constraints of cultivated land quality can also be alleviated to realize the sustainable utilization of cultivated land resources. In this study, a comprehensive evaluation system of cultivated land quality was constructed from the dimensions of the production (such as suitability, connectivity, and resistance) and the ecological stress. The production characteristics of cultivated land in China were evaluated and then graded from the grid scale. The k-means clustering method was adopted to determine the ecological stress factors. A four-dimensional spatial concept model was used to characterize the combination of "suitability- connectivity-resistance-ecological stress" of cultivated land. The comprehensive zoning of cultivated land quality improvement was established to combine the number of disadvantageous dimensions and the principle of relative advantage. The results showed that: 1) Production characteristics and ecological stress were integrated to construct the evaluation system of cultivated land quality. The classification was performed better on the quality characteristics of cultivated land resources. Effective support was also provided for the production-ecological coordination of cultivated land quality improvement. 2) There were significant spatial differences in the suitability, connectivity, resistance, and ecological stress of cultivated land resources. The cultivated land shared high and moderate suitability, indicating a decreasing trend from the east to the west. The spatial pattern of connectivity for the cultivated land was "high in the northeast and low in the southwest". There were widely distributed areas in a large quantity of cultivated land with moderate resistance. While there were spatially concentrated areas in the small quantity of high, low, and poor stress-resistant cultivated land. Specifically, the cultivated land with ecological stress was widely distributed in the Huang-Huai-hai Plain, Northern arid and semiarid region, Northeast China Plain, and Loess Plateau. 3) The areas of cultivated land quality were divided into six zones: conservation and utilization, suitability improvement, spatial optimization, facility improvement, comprehensive enhancement, and ecological restoration zone. Corresponding strategies were proposed for the construction, utilization regulation, and management of cultivated land, according to the characteristics of different zones. The finding can also provide a strong reference to guide and coordinate the improvement of cultivated land quality, according to the local conditions in the new era. The efficiency of resource allocation was enhanced to realize the national strategy of food security, such as storing grain on the land.