Potentiality for cultivated function recovery of non-grain cropland on the perspective of limitation-suitability-acceptability

Non-grain farmland can refer to the arable land for non-grain crop planting or converting its utilization into other agricultural purposes, such as forest land, orchards, and fish ponds. The practice can violate the farmland protection and land use policies, even threatening the national food security‌. The recultivation of the non-grain cultivated land is one of the most important measures to orderly restore the farmland. The spatial layout of cultivated land can also be optimized to curb the continuous decline of arable land. The purpose of this study is to construct a potential evaluation model for the cultivated function recovery of non-grain cultivated land. It was of great significance to the rational delineation of the spatial location and restoration sequence of the non-grain cultivated land restoration. Taking the land plots as the research units, the limiting factor was integrated with the weighted overlay analysis, with the emphasis on the regional limitation, cultivation suitability, and socioeconomic acceptability. Meanwhile, an empirical study was conducted to validate the model in Lingshui County, Hainan Province, China. The results show that: (1) The restricted land plots were removed, such as the cultivated land for the construction occupation, within nature reserves and on high mountains. Land parcels of recultivation were then distinguished with the high, relatively high, medium, and low potential, according to the farming suitability and the economic-social acceptability values. A scientific basis was provided for the reasonable decision-making on the restoration plots of the non-grain cultivated land. The spatial location was effectively evaluated to implement the tasks of non-grain cultivated land restoration. (2) There was some influence of the index values of the farming convenience factor. The restoration potential of the non-grain cultivated land was ranked between 0.11,0.58, indicating a middle-low level in general. Spatially, there was a situation pattern of the high value clustering and the low value densely spreading in the county. (3) The actual range of the non-grain cultivated land restoration basically coincided with the potential partitioning, indicating a high degree of credibility of the model. Better selection was also achieved in the construction plots for the non-grain-cultivated land restoration. (4) The centralized connectivity was combined with the scale of the plot. The 10 key non-grain cultivated land restoration areas were optimally delineated to spatially determine the implementation scope in the future. Much attention should be paid to the restoration and re-planting of the non-grain cultivated land, in order to combine with the regional limitations, cultivation suitability, as well as economic and social acceptability. The selection of the restoration plots enhanced the efficiency of the non-grain cultivated land restoration. Meanwhile, the grain cultivation area can be expected for the regional food security. The categorized remediation, multi-measure coordination, and dynamic monitoring can also be proposed to restore the non-grain cultivated land. The land parcels can be labeled as the engineering restoration, immediately restorable, and forest-grassland patches in the third national land survey.