Evaluation of the Remediation of Cultivated Land for Non-Grain Conversion Based on the “Resource Cost-Negative Effect-Remediation Potential” Framework: A Case Study of the Bohai Rim (BR) Region, China

Controlling the conversion of cultivated land to non-grain uses is of great significance for ensuring global food security. Currently, the research on the conversion of Main Grain Land (MGL) to non-grain uses lacks a theoretical framework that can support differentiated and targeted governance. In this study, a “Resource Cost-Negative Effect-Remediation Potential” (RC-NE-RP) evaluation framework for the conversion of cultivated MGL to non-grain uses was established based on the definition of “non-grain conversion of MGL” and the theory of the production function in economics, the negative effects of non-grain conversion of MGL and the remediation potential of non-grain land converted from MGL in the Bohai Rim (BR) region, China, during the period from 1990 to 2020 were quantitatively evaluated using an improved SBM model, and the non-grain land to be remediated in the BR region was zoned through cluster analysis. The results show that: (1) The process of non-grain conversion of MGL in the Bohai Rim region shows a trend of fast conversion followed by slow conversion, with increasingly significant characteristics of spatial differentiation. (2) For the period from 1990 to 2020, the negative effects of non-grain conversion generally exhibit an upward trend, and the negative effects of non-grain conversion in coastal economic zones are generally stronger than those in hinterlands; the remediation potential of non-grain land converted from MGL shows a downward trend followed by an upward trend, and the remediation potential of non-grain land in coastal economic zones is lower compared to hinterland areas. (3) The areas represented by Beijing and the Bohai Economic Rim (BER) are classified as priority remediation zones, and the other areas are classified as low-priority remediation zones. The BR region is divided into three types of zones for remediation, namely, Quantity–Quality Priority Zones, Quantity–Landscape Priority Zones, and Quality–Landscape Priority Zones. This study provides a scientific basis for the management and control of non-grain conversion of cultivated land and the protection of cultivated land.