以烤烟品种K326为材料，采用15N同位素示踪技术，研究了浏阳烟区不同施氮量对烟叶干物质积累和氮素吸收利用、残留及损失的影响。结果表明，烟株根、茎、叶各器官氮素累积比例为1：2.5：6.5。烤烟吸收的氮素58.14%～62.55%来自肥料，37.45%～41.86%来自于土壤。基肥氮利用率为28.25%～40.18%，追肥氮利用率为35.95%～69.62%。基肥氮利用率随着追肥用量增加而提高，追肥氮利用率随着追肥用量增加呈明显减小。在158 kg/hm2氮水平内，增加施氮量有提高烤烟肥料氮利用率（21.97%～23.55%）和土壤残留率（35.97%～39.47%）的趋势但不显著，肥料氮损失率随氮素水平增加而减小，变化范围36.98%～42.07%。在158 kg/hm2氮水平下，烟株干物质累积量、总吸氮量和肥料氮吸收量最大，分别为5321.05、97.17和60.78 kg/hm2，肥料氮损失率最低，为36.98%。%15N-labelled experiments were designed to study the effect of different nitrogen amount on dry matter accumulation and nitrogen uptake, residue and loss of flue-cured tobacco in Liuyang. The results showed that the nitrogen accumulation ratio of leaf, stem and root was 1:2.5:6.5. 58.14%-62.55% of N absorbed by flue-cured tobacco was derived from fertilizer under different N levels, while 37.45%-41.86% of the absorbed N was from the soil. Fertilizer N utilization efficiency (NUE) of base and topdressing fertilizer N was from 28.25% to 40.18% and from 35.95% to 69.62% respectively. NUE of base fertilizer N was increased with the increase of topdressing N, NUE of topdressing N was decreased with the increase of topdressing N. Under the 158 kg/ha N level, with the increase of N fertilizer, NUE and soil residual rate increased, from 21.97% to 23.55% and from 35.97% to 39.47%, but the increase was not significant. Fertilizer N loss rate decreased, from 36.98% to 42.07% under this condition. AT the 158 kg/ha N level, tobacco dry matter, total N accumulation, fertilizer N accumulation were the highest (5321.05, 97.17 and 60.78 kg/ha), and the fertilizer N loss rate was the lowest (36.98%).
展开▼
