西北地区制种玉米产量及氮素吸收对供氮水平的响应

【目的】针对我国制种玉米氮素吸收与累积规律不明确的问题，研究制种玉米生物量累积、产量形成和氮素吸收对供氮水平的响应，旨在为制种玉米高产高效绿色生产提供理论依据。【方法】以大面积制种的品种组合为试验材料，于2019—2020年开展田间定位试验。采用完全随机区组设计，共设置4个供氮水平，分别为只施底肥对照(CK)、168 kg N·hm^-2、240 kg N·hm^-2和320 kg N·hm^-2，研究不同供氮水平对制种玉米父母本生物量、杂交种产量和氮素吸收累积的影响。【结果】制种玉米父母本生物量累积随供氮水平的提高而提高，产量随供氮水平的提高先增加后保持稳定，N240处理同时实现了较高的产量、氮肥利用率和籽粒氮浓度，两年结果较为一致。N168处理在试验第2年达到较高产量，但氮浓度低于N240处理。母本秸秆及父本整株氮浓度均为高氮处理高于低氮处理；灌浆期母本实现最大生物量的临界氮浓度为15.08 g·kg^-1，收获期母本生物量与氮浓度呈线性相关。各追施氮肥处理的花后生物量两年间均大于花前，且随供氮水平的提...

Effects of Different Nitrogen Gradients on Yield and Nitrogen Uptake of Hybrid Seed Maize in Northwest China

【Objective】The law of nitrogen uptake and accumulation of maize in seed production in China is unclear. In view of this, the responses of biomass accumulation, yield formation, and the nitrogen uptake to nitrogen supply were studied in order to provide the theoretical basis for green and efficient hybrid maize seed production. 【Method】 Taking the parent varieties combination of large area seed production as the experimental material, the on-site experiment was carried out from 2019 to 2020. A completely random block design was applied to study the effects of different nitrogen gradients on parental biomass, grain yield and nitrogen uptake and accumulation of maize seed production. Four nitrogen gradients were set up as basal fertilizer control (CK), 168, 240 and 320 kg N·hm^-2, respectively. 【Result】The accumulation of parental biomass of hybrid maize seed production increased with the increase of nitrogen gradients. The yield of maize seed production increased at first and then remained stable with the increase of nitrogen gradients. N240 treatment achieved higher yield, nitrogen use efficiency and grain nitrogen concentration at the same time, which were consistent in the two years. The yield under N168 treatment was higher than that under N240 treatment in the second year, but the nitrogen concentration was lower than that under N240 treatment. The nitrogen concentration of the whole plant of female parent straw and male parent was higher in high nitrogen gradient treatment than that in low nitrogen gradient treatment. The critical nitrogen concentration of maximum biomass of female parent at filling stage was 15.08 g·kg^-1, and there was a linear correlation between female parent biomass and nitrogen concentration at harvest stage. The post-silking biomass of each topdressing nitrogen fertilizer treatment was higher than that of pre-silking stages in two years, and increased with the increase of nitrogen gradients. The change rule of post-silking nitrogen uptake ratio with nitrogen gradients was consistent with the biomass. There was no significant difference in yield level, biomass accumulation, and nitrogen uptake between N320 treatment and N240 treatment. Under the premise of comprehensive consideration of yield and hybrid seed quality, N240 could be regarded as the recommended nitrogen application rate for hybrid maize seed production in this region. 【Conclusion】 The optimal nitrogen application rate could increase yield and nitrogen use efficiency by regulating the ratio of nitrogen uptake for maize parents in pre- and post-silking in seed maize production. This study revealed that optimizing nitrogen application rate to stabilize nitrogen uptake in the pre-silking stage and ensure nitrogen supply after anthesis was the key to achieve high yield and nitrogen use efficiency of seed maize, and provided a theoretical basis for sustainable production of hybrid seed maize.