中国粮食生产与耕地变化的时空动态

 【目的】揭示1990-2005年中国粮食生产与耕地变化的时空动态特征,以及粮食生产对于耕地变化的敏感性。【方法】构建重心拟合模型和敏感度分析模型,对比分析耕地面积重心和粮食产量重心动态关系。【结果】中国粮食生产重心和耕地分布重心在空间上均表现为“北进中移”的态势,在移动方位上大致具有同向性。耕地重心沿着“西北—西南—东北”的轨迹共移动了17.3 km,粮食产量重心沿着“东北—西南—东北”的轨迹移动了223.3 km,两个重心之间的距离和粮食产量大致呈反向变化。当两者距离拉近时,粮食产量减少,当两者距离增大时,粮食产量增长。【结论】区域粮食产量增长受粮食单产、粮食播种面积等非耕地总量因素的影响日益明显;粮食产量变化对耕地变化的敏感性呈增强趋势。化肥、农药等物质投入的报酬递减趋势日益明显,粮食增产对耕地资源的依赖性也日益增强。保障粮食安全与耕地保护亟需创新机制和政策。

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.