世界上许多国家在大量施用化肥的同时,重视发展和利用绿肥。这样,不仅可以解决有机肥料不足,而且又能避免大量施用化肥造成的一些问题。如日本过去大量施用化肥,每亩施用量达877斤(1955年),近几年下降到347斤,而且在向复合肥料和稻草还田、绿肥压青等方向发展。美国、加拿大、澳大利亚也在积极发展苜蓿、三叶草等绿肥生产。不少国家还在有效地提高绿肥的 Many countries in the world, while using large amounts of chemical fertilizers, attach importance to the development and utilization of green manure. This will not only solve the problem of insufficient organic fertilizer, but also avoid the problems caused by the large amount of fertilizer. For example, Japan used to use a large amount of chemical fertilizers at a dosage of 877 kilograms per acre (1955) and dropped to 347 kilos in recent years. In addition, it has been increasing its use of chemical fertilizers and straw, and green manure. The United States, Canada, Australia are also actively developing alfalfa, clover and other green manure production. Many countries are still effectively raising green manure