Study On Tobacco Plant's Absorption And Distribution Of Nitrogen By Using ¹⁵N

In 2006, a trial was conducted to determine effects of different formulate of nitrogen forms and film-uncovering on growing, yield and quality , chamical components , N accumulation and N fertilizer utilization of flue-cured tobacco at Qujing of Yunnan province. the conclusion was induced in the following inspect :1 Effect of different formulate of nitrogen forms and film-uncovering on groing and quality of flue-cured tobaccoThe treatment of NH₄⁺-N:NO₃^--N was 7:3 and the film was covered could assure the growth of tobacco plant , but agronomic characters each target, the biology output (fresh weight and dry weight) as well as the production value were lower. When we chenge the ratio of NH₄⁺-N:NO₃^--N was 5:5 still covering the film ,tobacco each target was improved, especially after transplanting ,its growth and leaf chemical components were better than before, the TS, RS and product value were increased. The results indicated that increasing the ratio of Nitric nitrogen in base fertilizer could stimulate tobacco plant grow faster after transplanting.When NH₄⁺-N:NO₃^--N was 7:3 and film uncovering, its growth and top leaf aeras were better than NH₄⁺-N:NO₃^--N was 7:3 film uncovering treatment and NH₄⁺-N:NO₃^--N was 5:5 film uncovering treatment. Its K content , S/S , yield and production value were best,. The results showed that film uncovering expressed its advantages in the late growing stages, film uncovering could stimulate the expansion of upper leaves. The plant height, stem, size of largest leaf of film uncovering treatment obviously better than film covering ones, the upper leaves developed, aeras increased.2 Effect of different formulate of nitrogen forms and film-uncovering on Tobacco Plant′s Absorption and Distribution of NitrogenThe result of ¹⁵N experiment showed that the N that tobacco assimilated mainly came from base fertilizer. Add NO₃^--N in base fertilizer , the accumulation of NH₄⁺-N from base fertilizer obviously higher than NO₃^--N. Film uncovering could raise the ratio of N in rood, stem, middle leaf and upper leaf from base fertilizer, but it couldn't affect the ratio of top dressing N in tobacco plant. At the beginning time after transplanting, NO₃^--N in base fertilizer had the biggest function in the organization morphogenesis. The NO₃^--N in base fertilizer on the tobacco plant growth and development of a major role in the growth and development of the medium-term. NO₃^--N in topdressing obviously stimulate growth and development on the initial transplanting of tobacco plant, it also helped Tobacco to the rapid growth and development in the early time.With the advance of growing stages, the ratio of N from fertilizer in tobacco organs continuously declined, however, the ratio of N from soil in tobacco organs continuously increased. Stimulating effect cased tobacco plants absorbed more N from soil . Starts from the intermediate stage of flue-cured tobacco, tobacco absorbed nitrogen mainly from soil .3 Effect of different formulate of nitrogen forms and film-uncovering on Tobacco Plant′s N fertilizer utilization.The N fertilizer utilization from topdressing was higher than its from base about 5.48% in the treatment of NH₄⁺-N:NO₃^--N was 7:3 the film uncovering. Both base and topdressing N fertilizer utilization at the treatment of NH₄⁺-N:NO₃^--N was 7:3 the film uncovering was higher than the film covering one about 26.33% and 34.1%. Compare with these two treatments, the treatment of NH₄⁺-N:NO₃^--N was 5:5 film uncovering had the highest NH₄⁺-N (base)fertilizer utilization, but its NO₃^--N fertilizer utilization was lower. In total N fertilizer utilization, the treatment of NH₄⁺-N:NO₃^--N was 5:5 film uncovering was highest about 30.2%.