The Evolution Characteristics Of World Grain Supply-Demand And Flow Pattern From 1962 To 2016

Grain is the most basic element of human survival.Whether in the past,present or future,it has always been in a fundamental position in the development of human civilization.China is the largest developing country in the world with a large population.Although grain production can basically maintain self-sufficiency,in recent years,grain has also been imported in large quantities.In 2016,grain imports reached 25.76 million tons,ranking first in the world.In the moment when individual powers provoke troubles and launch trade wars with the purpose of harming China's interests,from the perspective of global grain supply-demand and trade,explore the changes in the spatial pattern of food flows in the past half century,and adjust China,s current dynamics of grain trends in a timely manner.The grain trade policy has important practical significance in coping with changes in international affairs and safeguarding national interests.Based on the statistics of the US Department of Agriculture from 1962 to 2016,this paper explores the spatial network Patterns of grain flows in major countries and regions in the world using the basic concepts of complex network theory.The results show 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.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.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.In summary,this paper explores the law of changes in grain supply-demand and flow pattern over a long period of time,expands the research field on grain,and provides relevant suggestions for how to ensure grain security in China,so it has very important theoretical significance and practical value.