The Spatial-Temporal Changes of Grain Production and Arable Land in China

【Objective】 The objective of this study is to reveal the spatial-temporal change characteristics of grain production and arable land changes in China as well as the sensitivity of grain yield changes to arable land from 1990 to 2005.【Method】 Contrastive analyzing the dynamic relationship of China's grain production and arable land changes by constructing models of gravity center fitting and sensitivity analyzing in this paper.【Result】 The results of study show that the gravity center of China's grain production and arable land distribution are both expressed as Move to northern and middle regions,which means both of them are almost the same in space.The center of arable land had been moved 17.3 km along the track of Northwest-Southwest-Northeast,and the center of grain production had been moved 223.3 km along the track of Northeast-Southwest-Northeast.The distance between the two centres of grain production and arable land was almost contrary to grain yield.When one center is close to the other,the grain yield reduced,otherwise grain yield increased.【Conclusion】 The increase of grain yield in China is affected by unit yield and planting areas,and the sensitivity of grain yield changes to arable land is enhanced.The diminishing returns of fertilizers and pesticides show that the dependence of grain production on arable land resources is increasing.It is very important to realize a mechanism and policy innovation for guarantee of national food security and arable land protection.