人类面临的根本问题之一,是居民的食品问题。现阶段,随着人口的迅速增加和食品生产增长速度的不均衡,这个问题变得极其尖锐。世界人口增长速度,在十九世纪每年约为0.5%,二十世纪前半期为0.8%,而在近五十年来人口激增,目前年增长率为1.9%。按照这样的速度增长下去,地球上的居民在三十五年以后就会翻一番。同时,全世界近二十年 One of the fundamental problems human beings face is the food issue of the residents. At this stage, the issue has become extremely acute with the rapid population growth and uneven growth of food production. The world population is growing at a rate of about 0.5% per year in the nineteenth century and 0.8% in the first half of the twentieth century. However, the population has soared in the past five decades, at a current annual rate of 1.9%. At such a rate, the population on Earth will double in 35 years. At the same time, the world nearly 20 years