不同氮肥运筹下玉米根系特征与产量的关系

Response of maize root traits to nitrogen application and its relationship with yield

明确玉米(Zea mays L.)根系性状对氮肥的响应特征及其与产量的关系,是揭示玉米氮营养机制、优化氮肥管理策略的基础。以供试玉米品种‘安农591’为试材,于2022年设置6种氮肥处理,即:不施氮(CK)、氮肥全部基施(N10)、基肥70%+拔节肥30%(N7∶3)、基肥50%+拔节肥50%(N5∶5)、基肥30%+拔节肥50%+大喇叭口肥20%(N3∶5∶2)、基肥20%+拔节肥40%+大喇叭口肥40%(N2:4:4),研究不同氮肥运筹下玉米根系性状的变化特征,并分析根系性状与产量的关系。结果表明,与CK相比,施氮提高吐丝期玉米根总长度、根表面积、根平均直径、根尖数、根体积、根组织质量密度和根系活力,降低比根长、根比表面积和根冠比。N7:3和N5:5处理的籽粒产量和全株生物量较高,其籽粒产量比N10处理提高6.6%~7.3%。施氮降低成熟期玉米根干物质分配比例,提高籽粒干物质分配比例。适当氮肥后移有提高氮肥农学效率的趋势。玉米产量与吐丝期比根长和根冠比呈负相关,与根总长度、根表面积、根尖数、根系体积和根系活力呈正相关(P <0.05)。在10种根系性状中,根总长度、根系活力、根表面积、根尖数和根冠比对产量影响较强,根平均直径、比根长、根表面积、根组织质量密度和根比表面积对氮肥农学效率影响较强。上述性状分别反映的是玉米产量潜力和氮肥利用率的重要根系性状。

Clarifying the response of maize(Zea mays L.)root traits to nitrogen(N)application and the rela-tionship between root traits and yield is the basis for revealing maize N nutrition mechanism and optimizing N management strategies.In the current study,taken‘Annong 591’as the tested variety,six N application treatments were conducted during the maize growing season in 2022,which were the control test without N application(CK),100%N fertilizer applied as basal application(N10),70%N fertilizer applied as basal application and 30%as top dressing(N7:3),50%N fertilizer applied as basal application and 50%as top dressing(N5:5),30%N fertilizer applied as basal application,50%as jointing fertilizer,and 20%as top dressing(N3:5:2),20%N fertilizer applied as basal application,40%as jointing fertilizer,and 40%as top dressing(N2:4:4).The effects of different N appli-cation treatments on the maize root traits were evaluated,and the relationship between root traits and yield was analyzed.The results showed that compared with CK,N application tended to increase the total root length,root surface area,mean root diameter,number of root tips,root volume,root tissue mass density,and root activity at the silking stage,while N application tended to decrease the specific root length,root specific surface area and the ratio of root to shoot.The greatest grain yield and plant biomass were observed in the N7:3 and N5:5 treatments.Compared with N10 treatment,N7:3 and N5:5 treatments increased grain yield by 6.6%-7.3%.Nitrogen applica-tion tended to decrease the dry matter proportion in the root,and tended to increase the dry matter proportion of grain at the maturity stage.Compared with N10 treatment,the treatments of N7:3,N5:5 and N3:5:2 tended to in-crease nitrogen agronomic efficiency,except for the treatment of N2:4:4.Maize yield(i.e.,grain yield and plant biomass)was negatively correlated with the specific root length and the ratio of root to shoot(P<0.05)at the silking stage,while it was positively correlated with the total root length,root surface area,number of root tips,root volume and root activity(P<0.05).Among the ten root traits studied,the root total length,root activity,root surface area,number of root tips,and the ratio of root to shoot had the strongest effects on the maize yield,while the mean root diameter,specific root length,root surface area,root tissue mass density,and root specific surface area had the strongest effects on nitrogen agronomic efficiency.These root traits are expected to reflect maize yield potential and nitrogen use efficiency.