为明确不同高密植夏玉米减施氮肥对其产量和干物质积累特征的影响，以夏玉米品种郑单1002为材料，研究了减施氮肥对夏玉米形态特征、产量、氮肥利用效率、干物质积累等方面的影响。结果表明：较高的密植水平和施肥均对夏玉米株高和穗位高有促进作用，且减施氮肥对植株形态特征无显著影响。D2显著提高了夏玉米产量24.74%，且该密植条件下N2处理对夏玉米产量产生不利影响；然而，N3和N4处理在2个密植条件下均未造成夏玉米显著减产。D2显著提高了夏玉米吐丝期和成熟期以及花后干物质积累量，但降低了花后干物质积累量对籽粒的贡献率；与N1相比，减施氮肥处理（N2、N3、N4）对干物质积累特征均无显著影响。此外，N2、N3和N4处理显著提高了2个高密植夏玉米氮肥偏生产力16.00%~22.90%，但氮肥农学利用效率仅在D2N4处理下获得16.32%的显著提高。本试验条件下，夏玉米采用75000株/ hm2的高密植水平，使用施氮量180 kg/hm2（氮肥减量20%）配施有机肥的施肥方式可以达到高产高效的生产目标。
In order to study the effects of nitrogen fertilizer reduction on grain yield and dry matter accumulation of summer maize in different plant densities, a two-factor randomized block test design was conducted with Zhengdan 1002, which analyzed the plant morphological characteristics, grain yield, nitrogen utilization efficiency (NUE) and dry matter accumulation of summer maize. The results showed that, higher panting density and nitrogen application both increased plant height and spike position, but nitrogen fertilizer reduction (N2,N3,N4) had no significant effects on plant morphological characteristics, compared with normal fertilizer application (N1). D2 increased summer maize yield by 24.74%, significantly. And N2 declined yield of summer maize in this planting density. While the treatments of N3 and N4 had no significant influence on yield of summer maize both in D1 and D2 planting densities. D2 significantly increased dry matter accumulation of silking and maturation stages, and amount of dry matter after anthesis, while it decreased contribution proportion of post-anthesis dry matter to grain. The influences of N2, N3 and N4 treatments had no significant different with N1 on dry matter accumulation characteristics. In additionally, treatments of N2，N3 and N4 significantly increased nitrogen partial factor productivity by 16.00%~22.90% under two planting densities, while the nitrogen agronomy efficiency only obtained significant higher increased by 16.32% in the treatment of D2N4. In conclusion, summer maize could achieve high yield and high efficiency aims with 75000 plant/hm2 planning density and nitrogen fertilizer reduction by 20% (180 kg/hm2) combined application with organic fertilizer.