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1调查目的随着人口的不断增加和耕地面积的日益减少,粮食危机显露出来,为了在有限的土地上打出更多的粮食,人类一方面在优化良种上下工夫,另一方面在提高地力上下工夫,这样化肥便扮演了重要角色。现在全世界每年使用的化肥总量在1 500亿kg左右。由于人们盲目追求产量,粮食确实增加了,但不可避免地带来了另外一个事实是:由于长期大量使用化肥,绿肥、农家肥减少了,使土壤肥力降低了,导致酸化、板结。据
1 The purpose of the survey As the population continues to increase and the area of arable land shrinks, the food crisis emerges. In order to produce more food on limited land, human beings are working hard to optimize good varieties, and on the other hand, they are working hard to improve their land. , This fertilizer will play an important role. The total amount of chemical fertilizers used every year in the world is around 150 billion kg. As people blindly pursue production, food has indeed increased, but it has inevitably brought another fact that due to the extensive use of chemical fertilizers for a long time, green manure and farmyard manure are reduced, which reduces soil fertility, leading to acidification and hardening. according to