氮肥分配对冬小麦-夏玉米轮作产量和氮肥效率的影响

通过田间小区试验研究了控制氮肥总量(N 420 kg/hm2)条件下氮肥分配对冬小麦/夏玉米轮作体系内的作物生物量、产量、纯收益、农学效率及肥料利用率的影响,结果表明,氮肥在冬小麦/夏玉米轮作体系的分配量及比例显著影响冬小麦/夏玉米轮作的产量、纯收益和氮肥的效率,冬小麦季施总氮55％ (N 231 kg/hm2)、夏玉米季施总氮45％ (N 189 kg/hm2)时,获得最高的轮作总产量(13 026 kg/hm2)和最大的净收益(22 146元/hm2),氮肥的农学效率和利用率较其它分配方式均有所提高,是晋南地区冬小麦/夏玉米轮作氮肥分配的适宜比例.就单季小麦而言,施N 189 kg/hm2可以获得较高的产量和较高的氮肥效率.值得指出的是,由于作物生长期间受春寒和夏旱的影响,冬小麦/夏玉米轮作体系内的氮农学效率和氮肥利用率均表现较低,仅分别为4.6 kg/kg和20.8％.

Influence of nitrogen fertilizer distribution on production and nitrogen use recovery within the rotation of winter wheat and summer maize

Effective nitrogen management remains one of the most challenging tasks for sustainable agriculture.This field experiment was conducted in a randomized design with four replicates to study on the influence of nitrogen distribution on biomass,yield,net return,nitrogen agronomic efficiency and nitrogen use recovery within the rotation of winter wheat and summer maize based on the amount of nitrogen controlled(N 420 kg/hm2).The results showed that the proportion of nitrogen distribution significantly affected the yield,net return and nitrogen use efficiency within the rotation of winter wheat and summer maize.Under the condition of 420 kg/hm2 nitrogen application,the proportion of 55%(N 231 kg/hm2)applied on winter wheat and 45%(N 189kg/hm2)for summer maize could help obtain the highest production(13 026 kg/hm2)and net return(22 146 yuan/hm2),and the agronomic efficiency and recovery of nitrogen fertilizer was increased.This indicated that the proportion of nitrogen distribution within the rotation of winter wheat and summer maize was feasible for southern region of Shanxi province.As far as nitrogen rate of wheat season was concerned,the nitrogen rate of 189 kg/hm2 could obtain higher yield and higher nitrogen efficiency.It was noteworthy pointing out that crop growth stage suffered from adverse weather leading to nitrogen agronomic efficiency and nitrogen use recovery was relatively lower with the average value only 4.6 kg/kg and 20.8%,respectively.