## 1 Introduction  
Cultivated land degradation is threatening food security and, as a result, affecting global and regional sustainability [1; 2; 3; 4; 5; 6]. Especially in recent years, with rapid economic growth, urbanization, and industrialization, a large amount of high-quality cultivated land has been occupied by construction in developing regions, including China, raising food security concerns. Strategies for sustainable cultivated land use have been increasingly discussed [7; 8; 9; 10; 11; 12]. Accordingly, the Chinese government has been endeavoring to improve grain production [4]. However, challenges remain due to cultivated land loss [13; 14; 15], shortage of the labor force and water resources [16; 17; 18; 19; 20], and climate change [21; 22]. To address these issues, China has implemented a series of policies and measures to protect cultivated land from the prospects of both quantity and quality, including the requisition-compensation balance of cultivated land (CLB), land-use regulation, basic farmland zoning, land consolidation, and rural land circulation [23; 24; 25; 26], which have played positive roles in ensuring China's food security. Requisition-compensation balance of cultivated land was implemented in 1998 [27; 28]. The policy requires that, if a government-approved construction project occupies cultivated land, the same amount of cultivated land must be supplemented elsewhere within the province to keep the balance of the total cultivated land. It was considered as a policy tool to balance the conflicts between the expansion of construction land and the protection of cultivated land. The local government can achieve the goal of land urbanization by developing cultivated land in underdeveloped areas. Since then, as one of the most primary approaches aimed to protect cultivated land, the policy has been widely implemented. From 2011 to 2015, 1,140,000 hectares of cultivated land were occupied by construction, and 1,707,333 hectares were supplemented in China. However, in recent years, many new problems have arisen in the practice. For example, the lack of reserve cultivated land resources, occupying the high-quality land but supplementing the poor by developing cultivated land in mountains, and the high costs [27; 28]. Therefore, some scholars have begun to consider how to improve this policy [27; 28], despite the fact that the Chinese government has implemented a massive investment for protecting cultivated land and, to some extent, does achieve the goal of balancing the cultivated land occupied by construction [29]. More importantly, projects under requisition-compensation balance of cultivated land have resulted in the spatial transference of cultivated land, which caused the quality of cultivated land to change accordingly and triggered arguments about the effect of these projects on grain productivity. Scholars documented that the programs under requisition-compensation balance of cultivated land could hardly achieve the ambitious goals for protecting cultivated land in terms of both quantity and quality, and even result in a decline in bio-productivity [30; 31; 32]. Thus, some recent studies have focused on how cultivated land change affects food security, notably grain productivity. To deeply understand the relationship, frameworks based on statistical data have been provided to characterize cultivated land change and its effect on grain yields over time [33]. Multi-scale measurements of spatiotemporal grain production changes and cultivated land resources have been also applied [34]. Some scholars used the barycenter and sensitivity methods to analyze the spatial shifts in grain production increases in China [35]. They found that the center of grain production had moved towards the north and west of China and reminded readers that the spatial mismatch of grain production and cultivated land could be adverse to the sustainability of agriculture. It is noteworthy that agricultural production is shaped by natural and socioeconomic factors [33].