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一、世界上生产和施用肥只有一百四十多年的历史,因其在农业增产中的巨大作用,产量增加很快,尤其是第二次世界大战以后,世界化肥的总产量每十年就翻一番。同时,化肥的品种也越来越多,养分的比例也在发生明显的变化。世界化肥发展的总趋势是向生产高浓化肥和复合化肥发展。另外,液体肥料的比重在少数国家明显增加.缓效化肥的研制和试用得到了重视。美国化肥的有效养分含量1950年为22%,1960
First, the history of producing and applying fertilizers in the world has only reached one hundred and forty years. Due to its tremendous role in increasing agricultural output, output has increased rapidly. After World War II, in particular, the total output of chemical fertilizers in the world has risen every decade Double At the same time, more and more varieties of fertilizers, the proportion of nutrients are also undergoing significant changes. The general trend of world fertilizer development is to produce high concentrated fertilizers and compound fertilizers. In addition, the proportion of liquid fertilizers increased significantly in a few countries, and the development and trial of slow-release fertilizers have received much attention. The effective nutrient content of US fertilizers in 1950 was 22% in 1960