黄壤烤烟追肥氮的积累、分配及利用

ACCUMULATION,DISTRIBUTION AND UTILIZATION OF TOP DRESSING N-FERTILIZER BY ^(15)N TRACER METHOD IN FLUE-CURED TOBACCO GROWING ON YELLOW SOILS

在田间条件下,利用15N示踪技术研究了黄壤2个点烤烟追肥15N积累、吸收比例、氮素利用率及15N在各器官分配。结果表明,烤烟于移栽后35d追肥,追肥15N积累于移栽后13周达到高峰,烟叶采收结束时(17周),追肥15N积累量分别为16.13和15.28kg/hm2,分别占烟株吸收总氮的16.95%～16.51%,追肥氮(15N)利用率为51.20%～61.73%,追肥中氮是烟株氮素重要来源之一,2个点追肥中15N在上部、中部、下部烟叶及茎+花中积累分别占吸收肥料总15N的32.30%～32.72%、32.68%～31.47%、17.65%～17.28%、27.22%～26.44%,60%以上追肥15N集中在中、上部烟叶。因此,烟株吸收追肥15N比例高、吸收时间拖后,追肥15N集中分布于中上部烟叶等均为黄壤烟区上部烟叶烟碱偏高的重要因素。

Field experiments were carried out to study the top dressing N uptake,accumulation,distribution and utilization rate in flue-cured tobacco using 15N tracing technique in two sites on yellow soil. When top dressing 15N applied in 5 weeks after transplanting（ WAT）,accumulation of 15N reached the peak value at the 13 WAT,and the accumulation amount of 15N were 16. 13 kg /hm2 and 15. 28 kg /hm2 in two sites,respectively in 17 WAT when the leaves was harvested. Ration of 15N,which came from top dressing fertilizer,were 16. 95% to 16. 51% ,and 15N utilzation rate were 51. 20% to 61. 73% in two sites,The top dressing 15N distribution at upper,middle,lower leaves and stem and flowers were 32. 30% to 32. 72% ,32. 68% to 31. 47% ,17. 65% to 17. 28% and 27. 22% to 26. 44% in two sites,respectively,with more than 60% of top dressing 15N accumulated in middle and upper leaves. Therefore, high nicotine contents on yellow soil were mainly resulted from more top dressing 15N absorbed,delaying 15N absorption of top dressing fertilizer and the high top dressing 15N use efficiency,as well as more fertilizer 15N concentrated in upper and middle leaves.