Effect of topdressing nitrogen on nitrogen cumulation and distribution of flue-cured tobacco in growing season

The test under field conditions studied the laws of nitrogen accumulations, and distributions in root, stem,leaf under local conventional nitrogen(N1), outside the root topdressing ammonium nitrate(N2), outside the root topdressing NaNO3 (N3) and plot experimental design with three replications each treatment. The results showed that: each treatment's flue-cured tobacco various organs nitrogen accumulation had no significant difference in early growth stage, in harvest every treatment had significant differences; N3 treatment's roots, stems, lower leaves, middle leaves, upper leaves nitrogen accumulation were respectively higher than N1 treatment by 28.98%、12.72%、4.46%、44.73%、7.27%；N2 treatment's roots and stems were respectively higher than N1 treatment by 11.14%、41.92%，lower leaves, middle leaves, upper leaves were respectively lower than N1 treatment by 18.23%、9.73% 、8.99% ；N3 treatment inproved nitrogen distribution to middle leaves and upper leaves, N2 treatment improved nitrogen distribution to stems and upper leaves. Comprehensive analysis showed that foliage spray could fill the needs of nitrogen nutrition flue -cured tobacco in chernozem region and corn stubble, and NaNO3 treatment was best.