氮肥管理对夏玉米冠层结构和氮肥吸收利用的影响

Effects of Nitrogen Managements on Canopy Structure and Nitrogen Absorption Utilization of Summer Maize

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。

In order to explore the four nitrogen management patterns, the field experiment was conducted to analyze the effects of nitrogen management models on canopy structure and nitrogen fertilizer utilization of summer maize. The results showed that nitrogen fertilization significantly improved yield components and grain yield of maize. Under the same amount of nitrogen, to compare the treatment of dressing nitrogen both in the large trumpet stage and silking stage with that just in the large trumpet stage, grains per spike increased by 28.5, harvest index increased by 11.3%, yield increased by 101 kg/ha. LAI at the grain-filling stage significantly increased with N dressing at silking stage, and thus the high LAI was maintained and reached maximal value at filling stage. In addition, SPAD values of summer maize also increased with nitrogen application, especially with the combination of the base fertilizer and big trumpet fertilizer. Plant height, stem diameter and ear height were all improved with nitrogen dressing at silking stage. ANUE and PFP increased by 232.3%, 60.9%, respectively, with low nitrogen application rate. Moreover, delaying of nitrogen application to silking stage, ANUE and PFP increased by 10.5%, 1.3%, respectively. Nitrogen dressing at silking in- creased the nitrogen accumulation in vegetative organs of summer maize, while reduced nitrogen accumulation in grain, resulting in decrease of nitrogen harvest index.