为探明施肥时期对玉米产量与氮素利用的影响,对干物质生产、氮素积累与分配进行研究。结果表明：12叶展一次性施肥处理产量较其它处理降低,干物质积累与氮素积累量少,氮肥利用效率低,说明氮肥后移需考虑植株前期对氮素的需要不可过晚。8叶展一次性施肥处理产量与基施处理产量与氮素积累量相当(施氮量为180 kg/hm2)或提高(75kg/hm2),植株干物质积累增加,冠层内茎叶干物质比例协调,生育后期穗下层茎叶干物重下降缓慢,氮素利用效率高。氮肥适当后移,特别是施氮量较小(75kg/hm2)情况下,可提高氮肥利用率。
英文摘要:
Field experiment was conducted to investigate the effects of postponing N application on nitrogen absorption, use efficiency of nitrogen fertilizer and grain yield in maize. The results showed that: applying nitrogen at 12-leaf stage decreased the dry matter accumulation, CGR at critical stage and nitrogen accumulation, thus leading to a low grain yield and use efficiency of nitrogen fertilizer. The grain yield of postponing N application at 8-leaf stage was similar with that (nitrogen applying amount=180 kg/hm2) or higher than that (nitrogen applying amount=75kg/hm2) of applying nitrogen as base fertilizer. Postponing N application at 8-leaf stage improved the nitrogen efficiency, slowed down the decrease of dry matter of stalk and leaf below the ear layer. Therefore, based on summer maize N uptake at different growth stages, postponing N application especially when N applying amount was low is a feasible N management practice.
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