近年来大田作物的化肥用量迅速增长似乎是世界性的趋势.由于施氮量增加,促进了分期施肥技术的发展.川田认为,追肥是一种补偿上壤环境缺陷的技术.在理想的土壤上不追氮肥也能高产,但这种土壤很少,而且难以通过土壤改良而普遍达到这种水平,现实问题是如何掌握重施化肥的效果.出井则提出追肥是一种补充土壤氮素肥力的技术. In recent years, the rapid growth of chemical fertilizer use in field crops seems to be a worldwide trend, and the application of staged fertilization technology has been promoted due to the increase of nitrogen fertilization.Kawata believes that topdressing is a technique that compensates for the environmental defects in soils. Nitrogen fertilizer can also be high yield, but the soil is very small, and difficult to achieve through soil improvement generally reached this level, the practical problem is how to grasp the effect of re-fertilization.I did put forward top dressing is a supplement of soil nitrogen fertility technology.