关键词: 粮食, 供需, 流动, 格局, 演变

Abstract:

Based on the statistical data from 1962 to 2016, this study implemented the basic concepts of complex network theory to discuss the spatial network forms of grain flow in major countries and regions in the world. The results showed that: (1) For a half century, the world's grain production has increased by 1.756 billion tons with an average annual increase of 2.09%. The world's grain consumption has increased by 1.703 billion tons with an average annual increase of 2.07%. (2) The world's grain output has increased by 345 million tons with an average annual increase of 3.02%. Among them, the United States, Argentina, and Ukraine are the main exporters, and China, the EU, and Japan are the main importers. (3) On the trend of the pattern of grain trade, the out-degrees and in-degrees of trade networks both have increased, indicating that the distribution of the world's grain output and input tends to be decentralized. (4) There is a significant difference in the node intensity and standard weight entropy in major countries and regions of grain trade. (5) The study found that although the out-degrees value of the United States grain trade is the largest, the homogeneity of the output spatial structure is the weakest and the grain output countries are very concentrated. Therefore, it is the weakness of the United States in grain trade. (6) China's standard weight entropy is higher, the proportion of input grain from countries is relatively small, and the homogeneity of the input structure is better, indicating that China has a stronger ability to cope with grain crisis and international trade disputes. The findings of this study reveal the evolution trend of the world's grain supply-demand, and flow pattern. It will provide a solid important reference for China's scientific formulation of agricultural development plans, grain trade policies, and responding to international changes.

Key words: grain, supply-demand, flow, pattern, evolution