Abstract: In order to explore the reasonable population construction of summer maize with reduction of N fertilizer,the effects of nitrogen fertilizer application on yield and nitrogen uptake and utilization of summer maize with different planting density in Linying County of Luohe City and Suiping County of Zhumadian City were analyzed.A summer maize cultivar Zhengdan 1002 was taken as the material,which was one of the leading cultivars in Huanghuaihai plain.The results indicated that dry matter accumulation,nitrogen accumulation,nitrogen transport and utilization of summer maize were significantly influenced by planting density and nitrogen fertilizer application.Close planting density was beneficial to increase dry matter accumulation at silking and maturation stages,promoted nitrogen accumulation,and increased nitrogen transport and utilization.However,it adversely affected nitrogen translocation efficiency and nitrogen translocation contribution proportion of summer maize.Dry matter accumulation and nitrogen accumulation both in silking and maturation stages increased significantly with nitrogen fertilizer increased, as well as nitrogen transport.However, nitrogen uptake and use efficiency decreased with nitrogen fertilizer increased.The yield was significantly increased by 5.18%—14.15% under close planting density.The nitrogen partial factor productivity (NPFP) was significantly increased by 6.65%—17.33% under close planting density.The more fertilizer application increased yield,while it decreased NPFP.By comprehensive consideration, at the planting density of 67 500 plants/ha, summer maize obtained higher yield with improved NPFP at the nitrogen fertilizer application of 180 kg/ha in Suiping and Linying.However,under the planting density of 75 000 plants/ha,the nitrogen fertilizer should be in range of 180—225 kg/ha according to the basic soil fertility,in order to obtain higher yield of summer maize.

Key words: Summer maize;Nitrogen fertilizer application rate;Planting density;Yield, Nitrogen uptake and utilization

摘要： 为探讨氮肥减施下夏玉米的合理群体构建，以黄淮海区域主栽夏玉米品种郑单1002为材料，在漯河市临颍县和驻马店市遂平县2个地点进行了不同密植条件下施氮量对夏玉米产量以及干物质和氮素积累、转运和吸收利用等的影响研究。结果表明：夏玉米干物质积累量、氮素积累量以及氮素转运和吸收均受种植密度和氮肥施用量显著影响；密植有利于提高夏玉米吐丝期和成熟期的干物质积累量，促进植株氮素积累，提高氮素转运量和氮肥吸收、利用效率，但对于氮素转运效率和氮素转运对籽粒的贡献率不利；增加施氮量提高了夏玉米吐丝期和成熟期的干物质和氮素积累量、氮素转运量，但降低了氮素吸收效率和氮肥利用效率。密植在增产（5.18%～14.15%）的同时使氮肥偏生产力提高了6.65%～17.33%；较高的施氮量获得高产，但降低了氮肥偏生产力。综合考虑，遂平和临颍试验点夏玉米在67 500株/hm²密植条件下，氮肥减施20%即施氮180 kg/hm²可获得较高的产量兼具较高的氮肥偏生产力；而在高密植75 000株/hm²条件下，根据地力水平适宜采取的施氮量为180～225 kg/hm²。

关键词: 夏玉米, 施氮量, 种植密度, 产量, 氮素吸收利用