增密种植下浅埋滴灌水氮减量对玉米根、冠物质分配与水氮利用效率的影响

Effects of reduction of nitrogen and water of shallow drip irrigation on material distribution of root and canopy and utilization efficiency of water and nitrogen of maize under dense planting

为探究增密种植下浅埋滴灌水氮减量对玉米根冠特性及水氮利用效率的影响,以传统畦灌常规施氮量(300 kg·hm^(-2))和常规灌溉量(4000 m^(3)·hm^(-2))为对照(CK),采用大田裂区试验,以传统畦灌常规灌量40%(W1)、50%(W2)和60%(W3)为主处理,以常规施氮量50%(N1)、70%(N2)和100%(N3)为副处理,研究90000株·hm^(-2)密度下浅埋滴灌水氮减量玉米根系分布、干物质积累转运、产量及水氮利用效率的变化特征。结果表明,不同土层根干质量均随灌溉量、施氮量的增加而增加,W2N3和W3N3处理20~40 cm、40~60 cm土层根干质量与CK的差异均不显著。吐丝前W2N3、W3N3干物质积累量与CK的差异均不显著,吐丝后W3N3显著高于CK,2018、2019年分别较CK高出9.74%和7.62%;W2N3、W3N2茎鞘、叶片转运量与CK的差异均不显著,W3N3处理2018、2019年茎鞘、叶片对籽粒贡献率则分别较CK提高了0.37%、0.43%和0.27%、0.56%。完熟期2018年CK处理的根冠比除与W1N2、W2N3和W3N3的差异不显著外,显著高于其他处理,而2019年不同灌溉量N3处理根冠比与CK的差异均不显著;单位根干质量产量除2019年W3N3处理与CK差异不显著外,各处理均显著高于CK。W2N3、W3N3处理根、冠物质分配合理且与CK产量、氮肥偏生产力的差异均不显著,灌溉水利用效率则分别提高94.15%、65.80%。增密种植下浅埋滴灌W2N3处理根系分布合理、根冠比协调且高产高效兼顾,可为西辽河平原浅埋滴灌增密种植下玉米高产高效栽培提供参考。

To explore the effect of reduction of nitrogen and water of shallow drip irrigation on root and canopy characteristics and water and nitrogen utilization efficiency in spring maize under dense planting,the root distribution,dry matter accumulation and transportation,yield and water and nitrogen utilization efficiency of maize under the density of 90000 plants·hm^(-2)were studied.The study adopted a split plot design with the irrigation level as main treatment including 40%(W1),50%(W2)and 60%(W3)of conventional irrigation and the nitrogen application as secondary treatment including 50%(N1),70%(N2)and 100%(N3)of conventional nitrogen fertilization by using the traditional border irrigation cooperated with the conventional nitrogen application as the control.The results showed that the root dry weight of different soil layers increased with the increase of amounts of irrigation and nitrogen application,and there was no significant difference in the root dry weight of CK,W2N3 and W3N3 in 20~40 cm and 40~60 cm soil layer.There was no significant difference in dry matter accumulation of W2N3,W3N3 and CK before spinning,but W3N3 was significantly higher than CK after spinning,9.74%and 7.62%higher than CK in 2018 and 2019.The difference of transport capacity of stem sheath and leaf among W2N3,W3N2 and CK was not significant,and the contribution rate of stem sheath and leaf to grain increased by 0.37%and 0.43%in 2018,and 0.27%and 0.56%respectively in 2019.There was no significant difference in root-shoot ratio between W3N3 and CK at silking stage,and the root-shoot ratio of CK was significantly higher than the other treatments except W1N2,W2N3 and W3N3 in 2018,and the root-shoot ratio of N3 in different irrigation amount had no significant difference with CK in 2019 at maturity stage.The yield per unit root dry weight of CK was significantly lower than that of other treatments except W3N3 in 2019.The material distribution of root and canopy of W2N3 and W3N3 were reasonable,and there were no significant differences in yield and nitrogen partial productivity with CK,however,the irrigation water use efficiency increased by 94.15%and 65.80%,respectively.The treatment of W2N3 under shallow drip irrigation had reasonable root distribution with proper root shoot ratio and high yield and high efficiency under dense planting.The study provided a theoretical reference for high yield and high efficiency in shallow drip irrigation under dense planting of maize in Xiliaohe plain.