Effects of Different Nitrogen Level on Nitrogen Absorption and Utilization of Flue-cured Tobacco under the High Proportion of Top Dressing

A field experiment was conducted to investigate the effects of nitrogen rate on nitrogen absorption and utilization of flue-cured tobacco under the dressing ratio of 3∶ 7.The results showed that,the increasing of nitrogen application in the range of 48～168 kg/hm2 was not led to soil nitrogen accumulation evidently after a growing season;By comparison with the treatment without artificial nitrogen fertilization,traditional chemical nitrogen rate(108.00 kg/ hm2),high chemical nitrogen rate(168.00 kg/ hm2) treatments significantly promoted the nitrogen uptake of tobacco,the yield of tobacco with nitrogen application at 108.00 kg/ hm2 and 168.00 kg/ hm2 was increased by 43.14 % and 49.25 %,tobacco output value could be promoted significantly(P0.05),but there was no significant difference in the decreasing of tobacco nitrogen use efficiency and tobacco nitrogen agronomic efficiency from the increased of artificial nitrogen under 70 % of fertilizer applied as top dressing.Tobacco sugar,reducing sugar content showed downtrend along with the increased application of chemical nitrogen and tobacco nicotone was opposite,but not significant,the sensory quality of flue-cured tobacco was not be affected significantly by the enrichment of artificial nitrogen fertilizer in the range of 48～168 kg/ hm2.From this study,it was suggested that 108.00 kg/hm2 chemical nitrogen fertilizer can effectively meet the flue-cured tobacco yield and quality demand under 70% of nitrogen fertilizer applied as top dressing in Nanxiong tobacco area.