苗期渍水条件下施氮量对直播油菜产量及氮素吸收利用的影响

Effects of Nitrogen Application Rates on Yield and Nitrogen Absorption and Utilization of Direct Seeding Rapeseed under Waterlogging at Seedling Stage

为探明四川盆地苗期渍水条件下稻田直播油菜的合理氮肥施用量,于2017-2018年在成都平原区开展大田试验,研究施氮量(0~225 kg/hm2)对直播油菜(种植密度30万株/hm2)产量和氮素吸收利用的影响。结果显示:施氮量为180~225 kg/hm2时,直播油菜成熟期农艺性状的指标值较高;籽粒产量和植株氮素积累量均随施氮量增加而增加,施氮量为225 kg/hm2时获得最高值;氮肥农学利用率和氮肥表观利用率随施氮量增加呈先增后降趋势,施氮量为180 kg/hm2时获得最高值;籽粒产量、植株氮素积累量、氮肥农学利用率、氮肥偏生产力和氮肥表观利用率在180 kg/hm2和225 kg/hm2两个施氮量处理之间均无显著差异。苗期渍水条件下,成都平原稻茬直播油菜合理施氮量为180~225 kg/hm2。

To explore the reasonable nitrogen fertilizer application rates of direct seeding rapeseed under waterlogging of seedling stage in Sichuan basin, a field experiment was carried out in Chengdu Plain from 2017-2018 to determine the effect of nitrogen application rate(0-225 kg/hm^2)on the yield and nitrogen absorption and utilization of direct seeding rape(planting density of 300 000 plants/hm^2).The result showed that,the index value of agronomic traits at the maturity stage of direct seeding rapeseed was higher when the nitrogen applied rate was 180-225 kg/hm^2. Grain yield and plant nitrogen accumulation increased with the addition of nitrogen application,and reached the maximum value when the nitrogen application rate was 225 kg/hm^2. The agronomic utilization efficiency and the apparent utilization efficiency of nitrogen fertilizer increased first and then decreased with the increase of nitrogen application,reached the maximum value when the nitrogen application rate was 180 kg/hm^2. There was no significant difference in grain yield,plant nitrogen accumulation,agronomic nitrogen utilization efficiency,partial nitrogen productivity and apparent nitrogen utilization efficiency between the nitrogen application rate of 180 kg/hm^2 and 225 kg/hm^2.Under the water-logging condition at seedling stage,the reasonable nitrogen application amount of direct seeding rapeseed in Chengdu plain paddy field is 180-225 kg/hm^2.