Evaluating cultivated land fragmentation and remediation zoning under planning management

Cultivated land has been one of the most important resources in agricultural production. Dynamically stable areas and the quality of cultivated land can greatly contribute to national food security and sustainable development. However, the cultivated land resources have been gradually fragmented and dispersed, with the rapid development of urbanization and industrialization. The cultivated land has been under serious threat in recent years. Therefore, this study aims to assess the suitability and necessity of cultivated land fragmentation for better cultivation zoning, in order to efficiently utilize the cultivated land resources and spatial layout. Accordingly, the background and progress were first combed to improve the research theory and logic fundamentals. The study area was selected as the typical mountainous county in the resource-oriented Dexing City in Jiangxi Province of China. 105 villages with cultivated land were taken as the evaluation unit. Secondly, a binding model was established for control and management. The "three zones and three lines" delineation was used as the reference. 20 indicators were also selected to construct an evaluation system for the suitability of cultivated land fragmentation, according to the three evaluation dimensions of production suitability, spatial agglomeration, and management control binding. The multi-factor integrated superposition was also evaluated for the appropriateness of cultivated land in the fragmentation management. Again, the three-dimensional Rubik's Cube spatial classification was used to construct the zoning guidelines. Production suitability, spatial agglomeration, and management control constraints were set as the X-, Y-, and Z-axis of the Rubik's Cube. The evaluation and grading results of each dimension were the nodes of the axes on the remediation and zoning. The results show that: 1) The better suitability of arable land resources production was 0.558, where 58 villages were more than the average value. The higher value was concentrated in the southwestern part of Dexing City; There was a uniform spatial agglomeration of arable land, with a citywide average of only 0.350. Less than half of the villages had a higher spatial agglomeration than the average, where the maximum of 0.577 was located in Jietian Village; The average value of the management control constraints was 0.075. There was a great variation in the villages, where the high values were concentrated mainly in the villages around towns and ecological red lines; The average value of the appropriateness in the management of cultivated land fragmentation was 0.711, and the appropriateness in the management of 53 villages was higher than the average, indicating the fine-fragmentation of cultivated land resources. 2) The comprehensive assessment showed that the 105 villages were divided into five zones, including the high-quality security, comprehensive improvement, facility optimization, intensive integration, and status quo maintenance zone, where the proportions of the cultivated land area were 38.36%, 12.01%, 19.11%, 17.84%, and 12.68%, respectively, according to the three-dimensional Rubik's Cube spatial classification. Differential remediation measures and strategies were also formulated to consider the different production suitability, spatial agglomeration, management and control constraints in each district. The finding can provide the theoretical basis and technical support to implement the diversified management and control measures in the different types of arable land resources, particularly in the cultivated land fragmentation remediation project.