油菜合理追肥是夺取高产的重要措施。国内外做了大量工作,如波兰等国关于甘兰型冬播油菜施用氮肥的试验和生产实践结果,总结出需氮总量的时间是:秋、冬季20—25%;春后50—70%;开花至成熟10—20%。江苏农学院认为在抽苔期和开花期是两个氮素代谢旺盛的时期,而开花期氮素需量更多。我们于1977年对我县14块亩产400斤油菜田块进行调查:高产田氮 Rational rapeseed top dressing is an important measure to seize high yield. At home and abroad, a great deal of work has been done. For example, the experiment and production practices of winter oilseed rapeseed in Poland and other countries have concluded that the total nitrogen requirement is 20-25% in autumn and winter and 50-70% in spring %; Flowering to maturity 10-20%. Jiangsu Agricultural College believes that during bolting and flowering are two nitrogen metabolism period, and nitrogen demand more during flowering. In 1977, we surveyed 14 counties of 400 kg of canola field in our county: high-yielding nitrogen in the field