喷灌施氮管理对春玉米产量及水氮利用的影响

为探究东北半湿润区喷灌水肥一体化条件下春玉米最佳施氮管理模式,于2017年在东北地区开展了不同喷灌施氮管理对春玉米生长、产量及水氮利用效率的田间试验研究.试验设置了3个总施氮量:N200(200 kg/hm²),N160(160 kg/hm²)和N120(120 kg/hm²),其中播种时统一埋施氮肥60 kg/hm²,苗期统一喷施氮肥10 kg/hm²,其余在拔节期和灌浆期按照3种施氮比例T1(1∶0),T2(2∶1)和T3(3∶1)通过水肥一体化喷施施入.结果表明:T1获得了最高的氮肥偏生产力、氮素收获指数和水分利用效率.增加施氮量能够促进产量的增加,但N200和N160的平均产量差异不具有统计学意义(P>0.05).所有处理中T1N200的产量最高,为12 489 kg/hm²;T1N160处理的氮收获指数最大,为74.98 kg/kg.施氮量增加,氮肥偏生产力随之降低,0~100 cm土壤内的硝态氮残留量随之增多.T1处理的平均硝态氮残留量最少,降低了氮素淋失的风险.综合考虑,推荐该地区采用总施氮量160~200 kg/hm²,其中播种期施基肥60 kg/hm²,苗期追施10 kg/hm²,其余在拔节期全部追施的施氮管理模式.

Effects of different nitrogen managements on spring maize yield,water and nitrogen use efficiency under sprinkler fertigation

To find out the optimal nitrogen management for spring maize under sprinkler fertigation in the semi-humid region of Northeast China, the field experiment was carried out in the northeast region in 2017, to study the effects of different sprinkler fertigation treatments on the spring maize grain yield, water and nitrogen use efficiency. Three treatments of the total nitrogen(N)application rates were 200 kg/hm²(N200), 160 kg/hm²(N160)and 120 kg/hm²(N120), respectively. During experiments, 60 kg/hm² N and 10 kg/hm² N were firstly applied in the sowing and seedling stages for all treatments, respectively. Rests of N were applied at three different N ratios: 1∶0(T1), 2∶1(T2), and 3∶1(T3)which were fertigated in the jointing stage and the filling stage, respectively. Results show that T1 obtains the highest nitrogen partial factor productivity(PFP_N), nitrogen harvest index(NHI)and water use efficiency(WUE). Grain yield increases with the N application rates increasing. But there is no significant difference in grain yield between N200 and N160(P>0.05). T1N200 produces the highest yield among all treatments, with 12 489 kg/hm². T1N160 has the highest NHI of 74.98 kg/kg. With the N application rates increasing, the PFP_N decreases, but the amount of the mineral nitrogen(NO^-₃-N)accumulated in the 0~100 cm layer of soil after harvest increases. T1 treatment has the lo-west residual NO^-₃-N in the soil, which reduces the risk of nitrogen leaching out of the 0~100 cm soil layer. Based on the results, the recommended nitrogen application is 160-200 kg/hm² in the semi-humid region of Northeast China, which contains 60 kg/hm² N applied in the sowing stage, 10 kg/hm² N fertigated in the seedling stage and rests of N fertigated in the jointing stage.