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通过大田试验研究不同氮肥管理模式下夏玉米群体结构和氮肥利用情况,探索节肥、高产、高效的夏玉米氮肥管理模式。结果表明,施氮显著改善夏玉米产量因子、提高产量。氮肥适量后移显著改善穗部性状,等氮量下大喇叭口期和吐丝期均追施氮肥处理与大喇叭口期追施氮肥处理相比穗粒数提高28.5粒,收获指数提高11.3%,增产101 kg/hm2。吐丝期施氮显著增加灌浆期LAI,使LAI峰值从吐丝期后移至灌浆期。施氮肥可增加夏玉米SPAD值,大喇叭口期追施氮肥可提高各生育时期玉米SPAD值;吐丝期追施氮肥可提高株高、茎粗、穗位高。适当降低氮肥投入,氮肥农学利用率和氮肥偏生产力分别提高232.3%、60.9%;氮肥用量相同时氮肥适当后移分别提高10.5%、1.3%。吐丝期施氮增加夏玉米成熟期营养器官的氮素积累,减少子粒的氮素积累,导致氮收获指数下降。
Field experiments were conducted to study the population structure and nitrogen use efficiency of summer maize under different nitrogen management modes, and to explore the management mode of nitrogenous fertilizer for summer maize with fatting, high yield and high efficiency. The results showed that nitrogen application significantly improved summer maize yield and increased yield. Appropriate amount of nitrogen fertilizer posteriorly significantly improved the panicle traits. Under the same nitrogen application, the nitrogen application rate was increased by 28.5 grains per panicle and the harvest index increased by 11.3% , Increase production of 101 kg / hm2. Nitrogen fertilization at silking stage significantly increased LAI at grain filling stage, which shifted LAI peak from silking stage to filling stage. Nitrogen fertilizer can increase the SPAD value of summer maize, topdressing nitrogen fertilizer at the big trumpet stage can increase the SPAD value of maize at each growth stage. Topdressing nitrogen fertilizer can improve plant height, stem diameter and ear height at the silking stage. Appropriate reduction of nitrogen input, nitrogen fertilizer agronomic utilization and nitrogen partial productivity increased by 232.3%, 60.9%; the same amount of nitrogen fertilizer when the appropriate back of the nitrogen fertilizer increased by 10.5%, 1.3%. Nitrogen fertilization at silking stage increased nitrogen accumulation in vegetative organs during summer maize maturity and reduced nitrogen accumulation in grains, resulting in a decrease in nitrogen harvest index.