Multifunctional evaluation and multiscenario regulation of non-grain farmlands from the grain security perspective: Evidence from the Wuhan Metropolitan Area, China

Non-grain production (NGP) represents a complex social phenomenon driven by a range of interests that involve agricultural development, livelihood security, and ecological preservation. It significantly alters the structure of agricultural production and vegetation cover, influencing regional grain supply and the multifunctional composition of agriculture. To achieve sustainable development goals related to grain supply and ecological stability, this study proposes a research framework for multifunctional evaluation and multiscenario regulation of non-grain farmlands (NGFs). First, NGFs in the Wuhan metropolitan area (WHM) were extracted based on land survey data to carry out multifunctional evaluation of NGFs, including production function, ecological functions and recreational function. Second, the SOM+K-means algorithm is used to identify and explore the multifunctional bundle characteristics of NGFs to determine the regulation priority order of NGFs. Finally, a multiscenario simulation of the rigid control scale and layout arrangement of NGFs from the grain security perspective is carried out. The research results show that (1) there are 1294.34 thousand ha of NGFs in the WHM, mainly of grain and non-grain rotation type (52.36 %). The production function is higher in the central and western Jianghan Plain areas than in the northeastern and southern hilly mountainous areas; the ecological functions are the opposite; the high-value areas of recreational function are mainly located around the built-up areas of the city. (2) Multifunctional bundles divide NGFs into seven categories and determine the order of regulation based on the principle of "production priority, functional diversity". (3) By setting different grain security scenarios, it is predicted that the rigid control scale of NGFs in the WHM in 2030 is 256.08–797.55 thousand ha. Divide and restore grain production in order of the priority zone for grain production, the reserve zone for grain production, the resilience zone for grain production, the ecological improvement zone and the agricultural improvement zone, so as to achieve a regulatory layout of strict control and adaptable regulation of NGFs. The research supports the regulation of NGFs in balancing grain security and ecological stability to promote sustainable agricultural production.