据估计,到2000年,人类约需有1.6亿公吨的氮肥,才能生产足够供应预计近70亿人口的粮食。除增建氮肥工厂外,也还有其他途径取得所需氮的一部分。一种是提高豆科植物的固氮能力;另一种是加强对非豆科植物固氮的研究。1967年美国发现一种沙漠植物叫做西部山艾树(western sagebrush)的根 It is estimated that about 160 million metric tons of nitrogen will be required by human beings in 2000 to produce enough grain to feed an estimated 7 billion people. In addition to the additional nitrogen fertilizer plant, there are other ways to obtain the required nitrogen. One is to improve nitrogen fixation capacity of legumes; the other is to strengthen nitrogen fixation of non-legumes. In 1967 the United States discovered a desert plant called the root of western sagebrush