氮肥后移对滴灌夏玉米源库特性及产量形成的影响

为研究氮肥后移对夏玉米叶片光合特性的改善、籽粒库容的调节以及增产效应,选择库容差异较大的玉米品种登海605和郑单958,利用滴灌水肥一体化方式设置氮肥全部(100%)底施、底施40%+十二叶展(V12)60%、底施40%+吐丝期60%和底施40%+十二叶展20%+吐丝期40%处理。结果表明,与一次性底施相比,氮肥分次施用处理登海605和郑单958穗位叶光合速率分别增加了14.4%~33.3%和6.1%~16.9%;籽粒建成期玉米素核苷含量、籽粒绝对含水量、体积分别提高了9.4%~53.0%、5.2%~13.5%、5.1%~13.5%和9.7%~45.9%、12.5%~36.4%、5.6%~30.6%;库容及光合速率的提高促进了籽粒灌浆速率,快速灌浆阶段的灌浆速率分别提高了0.66~2.24mg/(粒·d)和0.65~1.64mg/(粒·d)。最终2个品种的粒重及登海605的穗粒数显著提高,分别增产5.8%~13.6%和5.1%~12.4%。氮肥后移保证了夏玉米全生育期对氮素的需求,源库特性明显改善,产量显著提高,底施40%+十二叶展20%+吐丝期40%施肥方式效果最明显。

Effects of postponing N-fertilizer application by drip fertigation on the characteristics of source-sink and yield formation in summer maize

Aim of this study was to explore the effects of postponing N-fertilizer application by drip fertigation on photosynthesis improvement,kernel capacity regulation and yield-increasing effect in summer maize.Hybrids with different kernel sink capacity,Denghai 605 and Zhengdan 958,were taken as study object.Four nitrogen (N) fertilization treatments including N-fertilizer applied 100% at sowing (CK),40% at sowing and 60% at 12-leaf stage (V12),40% at sowing and 60% at silking stage,40% at sowing,20% at V12 and 40% at silking stage were implemented by drip fertigation.The effects of postponing N-fertilizer application on the characteristics of source-sink and yield formation were investigated.Compared to CK,dressing N at the late stages could increase photosynthetic rate of ear leaf by 14.4%-33.3% in Denghai 605 and 6.1%-16.9% in Zhengdan 958.Zeatin riboside content,water content and volume during the late lag period were increased by 9.4%-53.0%,5.2%-13.5%,5.1%-13.5% in Denghai 605 and 9.7%-45.9%,12.5%-36.4%,5.6%-30.6% in Zhengdan 958,respectively.The improvement in the characteristics of source-sink enhanced grain filling rate,and grain filling rate during the fast filling period increased 0.66-2.24 mg/(kernel·d) in Denghai 605 and 0.65-1.64 mg/(kernel·d) in Zhengdan 958.In the end,the kernel weight of the two hybrids and the ear kernel number of Denghai 605 were stimulated,and grain yield were improved by 5.8%-13.6% in Denghai 605 and 5.1%-12.4% in Zhengdan 958.In conclusion,postponing N-fertilizer application ensured the N requirement during whole period for summer maize,improved the characteristics of source-sink,and promoted grain yield.The treatment of 40% N-fertilizer applied at sowing,20% at V12 and 40% at silking stage showed the most obvious effect.