氮素追施对玉米花后光合特性和子粒灌浆特征的影响

Effects of Topdressing with Nitrogen on Photosynthesis and Grain-Filling Characteristics of Spring Maize after Anthesis

为进一步挖掘东北黑土雨养农业区春玉米增产潜力,为合理施氮提供理论依据,以玉米品种富民985为试验材料进行田间试验。设置5种施氮方式,氮肥1次性施入(CK)、底肥40%+拔节期追施60%(T1)、底肥40%+拔节期追施20%+大喇叭口追施40%(T2)、底肥40%+拔节期追施15%+大喇叭口追施30%+灌浆期追施15%(T3)、底肥40%+拔节期追施10%+大喇叭口追施30%+灌浆期追施20%(T4),研究不同处理玉米花后穗位叶SPAD值、净光合速率(Pn)、磷酸烯醇式丙酮酸羧化酶活性(PEPc)及子粒容重和产量差异,利用Logistic方程拟合玉米灌浆过程。结果表明,T4处理子粒产量显著高于其他处理和对照。与氮肥1次性施入(CK)相比,T4处理玉米灌浆期穗位叶Pn和PEPc显著提高了42.8%和20.6%,玉米有效灌浆期延长13.7 d,到达最大灌浆速率时间延后2.4 d,子粒容重提高1.2%。在东北半湿润雨养农业区,按照底肥40%+拔节期追施10%+大喇叭口追施30%+灌浆期追施20%方式施用氮素(T4)可以获得更多光合产物,延长灌浆时间,增加子粒重量,提高玉米产量。

To further investigate yield potential and N utilization of maize in the rain-fed agricultural area of Northeast China,a field experiment was conducted using spring cultivar Fumin985 as the experimental material.Five nitrogen fertilization treatments were implemented using drip fertigation:N-fertilizer applied 100%at sowing(CK),40%at sowing,and 60%at V6(T1),40%at sowing,20%at V6,and 40%at VT(T2),40%at sowing,15%at V6,30%at VT,and 5%at R2(T3),40%at sowing,10%V6,30%at VT,and 20%at R2(T4).And the SPAD value of ear leaf,net photosynthetic rate of ear leaf,phosphoenolpyruvate carboxylase activity of ear leaf,grain bulk density and yield were studied.The grain-filling processes of maize were analyzed by Logistic model to analyze the grouting parameters.The results indicated that grain yield(13901 kg/ha)of T4 was significantly higher than that of the other treatments.Compared to CK,the net photosynthetic rate of ear leaf,phosphoenolpyruvate carboxylase activity of ear leaf,active grain-filling period,maximum filling rate time,and the grain bulk density of T4 increased by 42.8%,20.6%,13.7 d,2.4 d,and 1.2%,respectively.Applying 40%of nitrogen fertilizer at sowing,10%at V6,30%at VT and 20%at R2(T4)can obtain more photosynthate,extend grain filling period,and increase 100-kernel weight of maize and grain yield in the rain-fed agricultural area of Northeast China.