中文摘要：

利用2000～2003年分县统计数据,以人均占有量为指标,重点研究21世纪初中国粮食主产区的空间格局及区域差异.研究结果表明：20世纪90年代后期以来,中国粮食生产重心进一步北移,同时出现“西扩”趋势.目前,20世纪90年代后期国家确立的粮食生产大县中近1/3人均粮食占有量已不足400kg,多分布在南方.全国3/4左右的余粮集中出产在东北地区、华北平原中南部地区、西部干旱、半干旱地区;2/3的余粮地区位于环境变化敏感地区,粮食产量波动大.这些地区的粮食丰歉直接影响到全国粮食市场价格的波动,中国粮食安全自然风险增大.加强上述地区的环境变化及粮食安全的自然风险研究,提高适应环境变化能力势在必行.

英文摘要：

Based on counties＇ statistic data in 2000-2003, this paper reveals new regional distribution and difference of main grain-output regions in China. For further understanding regional characteristics and natural risk of grain production, this analysis adopted four indices of the proportion of grain-sown area, the proportion of cultivated land, grain yield per gain-sown area and population density to group the main grain-output regions into six types by k-means Cluster in SPSS 11.0, and presented these results respectively in four geographical regions, namely, the Northeast China, the North China Plain, the oases in western China and the southern China. This study shows that the main grain-producing areas have shifted from the south to the north of China, and added newly in western China since the late 1990s. There was an obvious disparity among the bases of commercial grain production in the late 1990s. The per capita grain in about 1/3 China＇s main grain-producing counties that were designated by the Chinese government is below 400 kg; and most of these areas are located in southern China. At present, the surplus grain produced by the main grain-producing counties in Northeast China （including the eastern Inner Mongolia） is about 34.7% of the surplus grain of the whole country. The proportion of the surplus grain production in the main grain-producing counties in the south is very low. The surplus grain produced by the 43 main grain-producing counties of Hunan and Jiangxi provinces is only 5.2% of the whole country. The surplus grain produced by the 24 main grain-producing counties in Sichuan Province and Chongqing Municipality is less than that by the 25 main grain-producing counties in Hebei Province. It is obvious that the distribution of the main grain-producing counties has changed in China in the early 21 st century. In the 21st century, Northeast China, the middle-south of North China, and arid and semi-arid region of Northwest China produced 3/4 of surplus grains. The surplus grain in Northea