小麦在其生长发育过程中对氮素的吸收有两个高峰,一个在年前的分蘖盛期,占吸收总量的13.5％,另一个在年后的拔节——孕穗期,占吸收总量的37.3％,而当前豫北区小麦春季的追肥时期一般是在返青期,这个时期小麦吸收的氮素量仅占总吸收量的12.3％。通过连续三年把春季追施氮肥的时间由返青期推迟到拔节——孕穗期的倒二叶露尖时的试验表明,在氮肥施用量相同的情 Wheat in its growth and development of nitrogen absorption has two peaks, one in the years before tillering, accounting for 13.5% of the total absorption, the other in the years after jointing - booting, the total absorption Of the 37.3%, while the current spring wheat top dressing in Henan Province is generally in the spring greening period, the nitrogen absorbed by wheat during this period accounted for only 12.3% of the total absorption. Through three consecutive years of spring topdressing nitrogen from postponement of greening to jointing - booting tip of the second leaf tip when the test showed that the same amount of nitrogen fertilizer application