春玉米产量和施氮量对氮素利用率的影响

Effects of corn yield and nitrogen application on nitrogen use efficiency

提高氮素利用率是提高氮素收益、降低氮肥施用所带来的环境风险的重要途径。采用同一品种春玉米丰田6号,以无灌溉黑土为供试土壤,采用"3414"试验设计,经3年试验,对春玉米氮素利用效率与玉米产量和施氮量之间的关系进行了探讨。结果表明,氮肥利用率与产量呈显著的正相关,而与施氮量呈显著负相关。当玉米产量大于11 t/hm2,施氮水平控制在当地推荐施肥量时,氮肥利用率可高达45%以上;超过当地推荐施肥量,氮肥利用率随施氮量的增加急剧下降。当玉米产量低于6 t/hm2时,氮肥利用率徘徊在17%左右,并且随着施氮量的增加变化不明显。

Increasing nitrogen use efficiency （NUE） is an important way to increase the nitrogen profit and decrease the environmental risk from nitrogen application.This work studied the relationship between the NUE and yield and that between the NUE and nitrogen rates by using the same corn cultivar Fengtian No.6 on black soil without irrigation （dry farming）.The experiment was designed with ＂3414＂ based on the data of three consecutive years.The results showed that the nitrogen recovery efficiency （RE） was significantly positively correlated with corn yield and inversely correlated with nitrogen rates.When the corn yield was greater than 11 t/ha and the nitrogen was at the local recommended level,the RE was about 45％,but it dropped sharply with nitrogen rate beyond the local recommended nitrogen level.When the corn yield was lower than 6 t/ha,the RE was around 17％ and there was no significant changes in RE with nitrogen rates.