“食物来源与人口增长”问题,是一个十分庞大而复杂的问题,它联系到社会制度、生产技术、社会习惯、卫生条件、食物热量与营养……等许多方面。

According to the Yearbook of Food and Agricultural Statistics, Part one, Vol.Ⅷ, 1953, there are in the whole world altogether 13,300,000,000 hectares of cultivated lands (including orchards), constituting, roughly speaking, 9% of tillable land on earth, to say the most.