吐丝期自然干旱条件下灌水和施氮对玉米产量及氮素吸收的影响

设置大田试验,利用吐丝期自然干旱胁迫研究灌水(自然干旱、灌水30 mm、灌水60 mm,分别为W0、W1和W2)和施氮(0、100、200、300 kg/hm~2,分别为N0、N1、N2、N3)对玉米产量、干物质累积与分配、氮素吸收与利用的影响及其耦合效应,并探讨适宜的水、氮组合调控措施。结果表明,吐丝期自然干旱条件下灌水和施氮均显著影响玉米成熟期的产量、干物质累积量、收获指数、氮素吸收量及氮肥利用效率,且两种措施具有显著的交互作用。W2N3处理的玉米产量最高,达9 666 kg/hm~2。干物质累积量和氮素吸收量随灌水量、施氮量的变化趋势与产量类似,收获指数和氮素利用效率存在明显差异。W0N0和W1N0处理的收获指数相比其他处理显著偏低,说明干旱和缺氮限制干物质向子粒的转运分配。玉米施用氮肥的表观利用率、农学利用率和偏生产力在灌水条件下均显著高于自然干旱条件,随施氮量增加而逐渐降低,均在W2N1处理达最高。

Responses of Maize Yield and N Uptake to Irrigation and N Fertilizer under Natural Drought at Silking Stage

A field experiment was conducted to study the responses of grain yield, dry matter accumulation and distribution, N uptake and N fertilizer use efficiencies of maize to irrigation (including three irrigation rates:0, 30, and 60 mm, respectively, named as W0, W1 and W2, respectively) and fertilizer N application (including four N rates:0, 100, 200 and 300 kg/ha, respectively, named as N0, N1, N2 and N3, respectively) under natural drought condition at silking stage, aiming to provide references for mitigating drought and maintaining stable yield technique in maize production of the Northeast China. The results indicated that irrigation and fertilizer N application showed significant single and coupling effects on maize yield, dry matter accumulation, harvest index, N uptake and N fertilizer use efficiency. The highest yield of 9 666 kg/ha was observed in W2N3 treatment. Compared with grain yield, the responses to irrigation rates and fertilizer N rates were similar for dry matter accumulation and N uptake, but not for harvest index and N fertilizer use efficiency. The harvest index was lower significantly in W0N0 and W1N0 treatments than other treatments, indicating that drought and N deficiency limited the translation and distribution of dry matter from plants to seeds. The recovery efficiency, agronomic efficiency and partial factor productivity of N fertilizer were reduced significantly in the irrigation treatments, these items decreased with increasing N rates and reached the highest values in W2N1 treatment.