中文摘要：

从中国各类型生态系统（农田、草地、水域）的实际的食物生产能力出发,结合进出口产品中的食物部分,得出全国实际的食物供给能力,根据食物营养成分表中的转化率,将各类食物折算成人类生存所需的3大营养成分（热量、蛋白质、脂肪）的产量来表示,并利用ArcGIS进行草地和农田食物供给的空间分析。以2004年为例,中国实际食物供给能力为：热量1.601×1015kcal,蛋白质6.163×107 t,脂肪2.717×107 t。其中,中国内陆生态系统实际可供给热量1.454×1015 kcal,蛋白质4.996×107 t,脂肪2.074×107 t,分别达到了陆地生态系统生产潜力的32.46%、38.33%和41.12%,内陆生态系统食物供给还有较大的增长余地。在小康水平下,中国的食物热量、蛋白质、脂肪分别可以供养人口19.12亿,20.84亿和11.03亿人,按照2010年营养目标和2020年全面小康目标,热量和蛋白质的供给已经较为充足,而脂肪的供给有所不足,今后需要注重油脂作物的种植和生产。结果还表明：中国的食物供给能力中,农田占据了绝大部分,不过比例有下降的趋势,从1998年的84.66%,下降到2004年的74.72%;草地和水域生态系统所提供的食物所占比例分别为4.83%~5.80%、6.02%~7.51%,波动较小;净进口食物所占比例逐年增长,1998年仅为4.04%,2004年增加到13.82%。通过平衡模型计算,在温饱、小康、富裕水平下,2004年中国可以供养的人口分别为：15.34亿,15.00亿和14.11亿,这表明,如果能够优化种植结构,合理配置植物性食物向动物性食物转化比例,均衡营养消费结构,中国实际食物供给较为充足。

英文摘要：

The actual food provision of China is calculated by using production data（survey data and statistical data） of cropland,grassland and aquatic ecosystems as well as import and export food data.Through the food-nutrition converting formula,we can calculate the total food nutrition production of China during 1998-2004.Taking the year of 2004 as an example,China can provide 1.601×1015 kcal（kilocalories） of food energy,6.163×104 million kg of protein and 2.717×104 million kg of fat,in which 1.454×1015 kcal of food energy,4.996×104 million kg of protein and 2.074×104 million kg of fat are from the terrestrial ecosystems——cropland,grassland and inland-aquatic ecosystems.Productions of food energy,protein and fat from terrestrial ecosystems amount for 32.46%,38.33% and 41.12% of their potential respectively,implying that there will be some increasing space of actual food provisions.China could supply food energy,protein and fat for 1912 million persons,2084 million persons and 1103 million persons respectively under full well-to-do life in 2004.According to the nutrition goal and the forecasted population of 2010 and 2020,provisions of food energy and protein are theoretically sufficient,while food fat is deficient,implying that production of fat and oil food needs enhancement.It is also found that a majority of the total food is supplied by cropland,although the proportion has a decreasing trend,from 84.66% in 1998 to 74.72% in 2004.Food supplied by the grassland and aquatic ecosystem accounts for 4.83%-5.80% and 6.02%-7.51%,respectively.The proportion of net-import food has an increasing trend,from 4.04% in 1998 to 13.82% in 2004.Food-population-provision model and nutrients-balancing model are used to calculate the population that China can support.Results show that if foods on the first trophic level such as grain,beans and oil-crops were appropriately converted into foods on the second trophic level such as meats,China can supply food for 1.534,1.500 and 1.411 billion people under primary well-to-d