氮肥用量对两种不同类型玉米杂交种物质生产及氮素利用的影响

旨在探明东北春玉米不同类型杂交种物质生产及氮素利用特征及其与产量的关系。本文以不同类型杂交种代表性品种郑单958(ZD958,Reid×唐四平头模式)和先玉335(XY335,Reid×Lancaster模式)为试验材料,2014年和2015年设置5个氮肥水平0 kg hm–2(N0)、100 kg hm–2(N1)、200 kg hm–2(N2)、300 kg hm–2(N3)和400 kg hm–2(N4)]和2个种植密度(67 500株hm–2和90 000株hm–2)试验,比较研究了不同类型玉米杂交种干物质与氮素积累、运转及氮素利用的差异规律。结果表明,两年XY335品种的最高籽粒产量均高于ZD958,最优氮肥施用量明显降低4.8%~10.6%;相比ZD958,不施氮处理,两种种植密度下XY335品种干物质积累能力及物质运转效率都明显降低,而施氮条件下XY335品种的干物质积累量、花后干物质量及干物质运转效率均增加,同时增幅随着施氮量增加逐步提高,且在高密度条件下优势更为明显。开花期XY335叶片与茎鞘氮素含量显著高于ZD958(P0.05),而成熟期由于其较高物质的运转效率表现出明显较低的数值,籽粒氮素含量在高密度下差异较小,而低密度条件下相对ZD958显著提高(P0.05)。施氮条件下XY335品种花前、花后氮素积累量和氮素积累总量均高于ZD958,其中叶片中氮素的转运对籽粒的贡献率显著较高(P0.05)。两种种植密度处理最优施氮条件下XY335氮素利用效率和氮素吸收效率均显著高于ZD958(P0.05),而氮农学利用率和氮肥偏生产力差异不显著。可见,高密度条件下XY335类型品种表现出明显较高的物质积累能力以及花后物质运转对籽粒的贡献率,获得较高的氮素利用效率,表现出明显高氮高效的品种特征,因此生产上建议,东北春玉米区高密度种植条件下该类型品种在较高氮肥施用量时易获得高产高效。

Effects of Nitrogen Application Rates on Dry Matter Productivity and Nitrogen Utilization of Different Type Maize Hybrids

To understand the relationship between dry matter productivity, nitrogen utilization and grain yield of spring maize hybrids in Northeast China, we conducted a field experiment in 2014 and 2015. Using two maize hybrids (Xianyu 335 and Zhangdan 958), under two planting densities (90 000 plants ha^-1 and 67 500 plants ha^-1) and five N application rates 0 kg ha^-1 (N0); 100 kg ha^-1 (N1); 200 kg ha^-1 (N2); 300 kg ha^-1 (N3); and 400 kg ha^-1 (N4)]. The average maximum grain yield in two years was higher in Xianyu 335 (XY335), while, the optimum N application rate was 4.8%-10.6% lower than that in Zhengdan 958 (ZD958). Compared with ZD958, total dry matter accumulation, dry matter accumulation after flowering, and dry matter translocation efficiency of XY335 were higher in nitrogen treatments, but lower in treatments without nitrogen application. At the same time, dry matter accumulation and dry matter translocation efficiency were increased gradually with increasing N application in XY335, especially under high density plantation. N concentration in leaf and stem of XY335 was different, showing higher at silking (P<0.05) and lower at harvest, which was due to better translocation efficiency in XY335 than in ZD958 after silking. The grain N content had small difference between two cultivars under high plant density, and significantly increased in XY335 under lower plant density (P < 0.05). In nitrogen treatments, XY335 had higher N accumulation at pre-silking and post-silking and significantly higher (P < 0.05) contribution of leaf N translocation to grain yield was than ZD958. At optimal nitrogen application rate, N use efficiency(NUE) and N recovery efficiency(NRE) were significantly higher (P < 0.05) in XY335 under both planting densities, while agronomic nitrogen efficiency (ANUE) and partial factor productivity from applied N (PFPN) were not significantly different between XY335 and ZD958. In XY335, NUE was significantly higher under high planting density due to higher dry matter production and better translocation efficiency during filling stage. Our results suggest that XY335 is a high nitrogen efficient (HNE) spring maize variety in the northeast of China, and can be better used to obtain high yield and high efficiency in intensive farming.