论文以人粮关系为基础,构建了土地资源承载指数(LCCI)模型,从全国、分省、分县3个空间尺度定量评价了1949~2005年中国土地资源承载力演变的时空格局,并以2005年为代表年份,分类讨论了中国264个牧区(半牧区)县、663个城市地区和592个贫困县(区)的土地资源承载力。研究结果表明:①1949~2005年,中国土地资源承载力逐步增强,人粮关系趋于均衡;②1980~2005年,中国粮食盈余省份增多,人口超载省份减少,人粮关系趋于改善;③1980~2005年,中国粮食盈余县域在增加,人口超载县域在减少,人粮关系总体趋于平衡;中国分县土地资源承载力格局基本稳定,粮食主产区的空间集聚效应越来越明显,对区域乃至全国的人粮平衡作用日益突出;④草地畜牧业大大提高了中国牧区、半牧区的土地资源承载力,受人口集聚效应影响的城市地区以人口超载、粮食调入为主要特征,中国贫困地区2/3以上的县域仍处于人口超载或临界超载状态,人粮矛盾突出。

With the increase of population, land carrying capacity and food safety have been attracted great attention worldwide. From the point of man-grain relationship, based on GIS techniques,by setting up the land carrying capacity(LCC) and the land carrying capacity index(LCCI) models, this paper firstly analyzes the spatial-temporal dynamic patterns of land carrying capacity of China between 1949 and 2005 at county, province and country level. Choosing 2005 as the typical year, this paper then evaluates the land carrying capacity of 264 pastoral(semi-pastoral)regions, 663 urban regions and 592 poverty-stricken regions of China. The result shows that: (1) From 1949 to 2005, with the increase of grain production, the land carrying capacity of China has been improved conspicuously, but for the rapid population growth, it still only balances with the low level grain consumption. (2) Over the last 25 years (1980-2005), the number of overloading provinces decreased from 23 to 15 and the man-grain relationship was bettered gradually, but there were more overloading provinces than surplus provinces in China. (3) At county level, there were 1572 overloading counties in 1980 whic accounted for 68.26% of the total with a population of 649 million, while in 1990,2000 and 2005, the number of overloading counties was 1066, 1133 and 1087 respectively,indicating that the man-grain relationship has been improved obviously during the past 25 years; as for spatial distribution, the surplus counties are mainly concentrated in agriculture developed regions, such as Northeast Plain, North China Plain, Middle and Lower Reaches of the Yangtze River Plain etc., and overloading counties are mainly located in regions with poor natural environment and low grain production capacity, such as Northwest China, Tibetan Plateau and Loess Plateau etc. and economy developed urban regions, such as Beijing, Tianjin and Shanghai etc. (4) Grassland husbandry led to great improvement of the land carrying capacity of pastoral and semi-pastoral regions, while urban regions were overloaded due to population concentration and more than half of the poverty-stricken regions were overloaded with critical natural environment and poor economic condition.