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，分别记为W0、W1和W2）和施氮（0、100、200、300 kg N/hm2，分别记为N0、N1、N2和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，为东北雨养玉米的抗旱减灾稳产技术提供依据。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。所有处理中，W2N3处理的玉米产量最高（9666 kg/hm2），较W0N0处理（3016 kg/hm2）增产221%。相比自然干旱条件（W0），灌水显著提高玉米产量，但两个灌水量之间无显著差异。施氮后玉米产量显著提高，W0条件下随施氮量增加持续提高，而W1和W2条件下在施氮200 kg/hm2时达到平台。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，而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籽粒的转运分配。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，同时随施氮量增加而逐渐降低，均在W2N1处理达到最高。综合考虑玉米产量和氮肥利用率，确定施氮200 kg/hm2基础上配合补充灌水60 mm为应对吐丝期严重干旱的最佳水、氮组合措施。
英文摘要:
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 N/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 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 9666 kg/ha was observed in W2N3 treatment, which was 221% higher than that of 3016 kg/ha in W0N0 treatment. Irrigation increased significantly maize yield, while no differences was observed between the two irrigation rate treatments. Moreover, maize yield increased significantly when fertilizer N was applied, it improved continuously with increasing N rates in W0 treatments but reached plateaus when 200 kg N/ha was applied in W1 and W2 treatments. 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 highest values in W2N1 treatment. In conclusion, based on the performances of grain yield and N fertilizer use efficiency, the supplementary irrigation of 60 mm with applying 200 kg N/ha was considered as a recommended irrigation and fertilizer N management practice for coping with severe drought at silking stage.
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