为进一步挖掘东北黑土雨养农业区春玉米增产潜力，并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5种施氮方式：氮肥一次性施入（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）及籽粒容重和产量差异，利用Logistic方程拟合玉米灌浆过程。结果表明，T4处理籽粒产量（13901 kg/hm2）显著高于其它处理和对照。与氮肥一次性施入（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13.7d，到达最大灌浆速率时间延后2.4d，籽粒容重提高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，增加籽粒重量，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 Fumin 985 as the experimental material. Five nitrogen fertilization treatments including 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) were implemented by drip fertigation. 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 (13901kg/hm2) of T4 was significantly higher than other treatments. Compared to CK, 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%, 13.7d, 2.4d, and 1.2% respectively. N-fertilizer applied 40% 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.

吉林省科技发展计划项目(20210202011NC, 20210203153SF, 20220302002NC, 20220508095RC和202203022003NC)。