氮肥后移对烤烟氮素吸收、利用及品质的影响

为研究氮肥追施比例对烤烟氮素吸收、利用、化学成分及感官质量的影响,以烤烟品种NC55为材料,运用15N同位素示踪技术进行了不同基追肥比例的田间试验。结果表明,提高氮肥追施比例,烟株各器官及整株对基肥氮的吸收量减少,追肥氮的吸收量增加；当追肥比例为50%时,整株对肥料氮的吸收量最高。随追肥比例增加,烟株各器官对土壤氮的吸收量呈先增加后降低趋势,当追肥比例大于30%时,茎秆、叶片及整株的土壤氮吸收量显著降低。随氮肥追施比例增加,基肥氮的利用率提高,追肥氮的利用率降低,肥料氮的利用率先增加后降低,以追肥比例为50%时最高。增加追肥比例提高了烟叶感官质量,以追肥比例50%时最好,追肥比例再增加,品质降低。本试验条件下,氮肥追施比例为50%是兼顾氮素利用和品质的最佳处理。本研究为烤烟氮肥的合理施用提供了理论依据。

Effect of Postponing N Application on Nitrogen Uptake, Utilization and Leaf Quality of Flue-cured Tobacco

To clarify the effect of nitrogen fertilizer topdressing ratio on nitrogen uptake, utilization, chemical components and sensor quality of flue-cured tobacco, a field experiment of different basal-topdressing ratios was conducted on cultivar‘NC55’by using 15N tracer technique. The results showed that improving the topdressing ratio decreased the basal fertilizer nitrogen uptake amount of different organs and total plant, but increased the topdressing fertilizer nitrogen amount. The treatment with 50% nitrogen topdressing had the highest fertilizer nitrogen uptake amount. With the improving of topdressing ratio, the soil nitrogen uptake amount increased firstly, and then reduced. The soil nitrogen uptake amount of stem, leaf and total plant decreased significantly when the topdressing ratio exceeded 30%. With the improving of topdressing ratio, the basal fertilizer-N use efficiency increased, but that of topdressing decreased, and the whole fertilizer-N use efficiency increased firstly, then reduced, and the highest fertilizer-N use efficiency was achieved with 50% nitrogen topdressing. The leaf sensory quality improved with the increasing of topdressing ratio until up to 50%, and it became worse if the ratio exceeded 50%. Under the field fertility of this experiment, 50% nitrogen top dressed was the optimal treatment taking account of nitrogen utilization and quality. The finding provided a scientific basis for rational application of nitrogen fertilizer of flue-cured tobacco.