Regional differences, spatial temporal evolution and dynamic evolution of food security in China.

Food security is the cornerstone of national security. It is urgent to scientifically and reasonably construct a food security assessment system and objectively measure the actual development level of China's food security. This is an important issue to enhance the modernization level of China's food security governance system and governance capacity. Constructing evaluation indicators for food security from a theoretical perspective, analyzing the spatiotemporal changes in China's food security, and expanding the theoretical perspective of food security research. At the same time, it provides ideas for the construction and improvement of China's long-term food security guarantee mechanism, and also provides scientific reference for world food security. The food security level of 30 provinces and cities in China from 2011-2021 was measured by using the Entropy weight TOPSIS model. The spatial characteristics and regional differences of China's food security were analyzed using the Standard Deviation Ellipse technology, Moran's index and Dagum Gini coefficient. The dynamic evolution process of food security level development was based on Markov Chain model. The food security scores of all regions in China showed three stages of fluctuation, balance and growth from 2011 to 2021. The spatial distribution of China's food security level was developing from northeast to southwest, and shows spatial autocorrelation. Regional differences were the main source of regional disparities in China's food security level. The evolution of China's food security level had shown significant spatial self strengthening characteristics and spatial spillover effects. The spatial pattern of China's food security presented a significant expansion feature along the 'Northeast Southwest' axis. The spatial differentiation of food security was showing a strengthening trend, and the regional coordination mechanism urgently needs to be improved. The root cause of regional differences lied in the imbalance between main production and main sales areas, with a dual lack of policy compensation and market mechanisms.