# Urbanization and Grain Production Pattern of China: Dynamic Effect and Mediating Mechanism
## 6 Conclusions and Insights  
In this study, panel data of 30 Chinese provinces from 1996 to 2018 were used as the sample, the entropy method was adopted to measure the urbanization, and the GPP was characterized by the grain production concentration index (GPCI). Based on the characteristics of changes in the GPP acquired using the SDE-COG model, a dynamic spatial panel econometric model was built, and Sys-GMM was adopted to analyze the direction and magnitude of urbanization's effect on the GPP. Then, a spatial mediating effect model was adopted to identify the transmission paths by which urbanization affected the GPP through cropland utilization, planting structure adjustment, and agricultural technology progress. Firstly, China's grain production COG showed a spatial distribution pattern transferring northeastward. Secondly, changes in the GPP had a significant time lag effect and spatial spillover effect. Thirdly, urbanization had a significant negative effect on the GPP--i.e., urbanization hindered the increase in GPCI. Fourthly, urbanization indirectly affected the GPP through the allocation effect of cropland utilization, the structural effect of planting structure, and the innovation effect of agricultural technology progress. Here, the mediating effect of the planting structure was more profound. The findings in the study could provide a new perspective for furthering our understanding of the evolutionary patterns and action paths of China's GPP and bring insights into the promotion of urbanization and food security in other developing countries. Since the reform and opening up, China's GPP has undergone profound changes. Policymakers should correctly understand the historical law of grain production transfer according to the pattern of \"northern grain to the south\" and give full play to regional comparative advantages to scientifically plan grain production and reasonably allocate advantageous production areas. The negative effects of urbanization on the GPP and the presence of mediated transmission paths implied that the transformation of old and new dynamics as well as urbanization progress to high-quality development drives the spatial mobility of agricultural production factors and induces changes in cropland utilization and planting structure adjustment. Thus, the GPP is affected. The reallocation effect and technological progress also weakened the negative effect of urbanization on the GPCI. The presence of spatial effects requires policymakers to pay constant attention to the structural changes triggered by the spatial flow of factors, promote agricultural marketization reform, and give play to the decisive role of the market in factor resource allocation and the guiding role of policymaking. The GPP is affected by regional differences in internal and external factors such as natural endowment conditions, socioeconomic development, and farmers' production decisions. Therefore, policymakers should grasp the heterogeneity of urbanization and grain production in different regions and balance the intrinsic structural changes in the factor structure of agricultural production and the extrinsic dynamic changes of market-based incentives. Urbanization development strategies must be formulated in accordance with local conditions, and the coupling and coordination of urbanization and grain production must be planned on the whole to promote the agricultural marketization reform. Policymakers must give play to the decisive role of the market in factor resource allocation and the guiding role of policymaking. The level of intensive cropland utilization must be improved, and the production structure must be optimized according to local conditions. Good regional interaction and communication between structural adjustment and grain production must be maintained to alleviate the impact of urbanization. In the meantime, urbanization in different dimensions such as population agglomeration, land scale, and economic growth must be gradually coupled, coordinated, and unified.