Effects Of Drought Stress And Different Periods Of Filling Water On Yield And Quality Of Flue-cured Tobacco

To investigate the effects of drought stress on dry matter accumulation,yield and quality of flue-cured tobacco and optimize the water management measures,this paper analyzed the change rule of dry matter accumulation,economic characters,physical properties,chemical components and aroma substance in controlling soil water content at different stages.The results of the study are as follows.1.The dry matter accumulation of stem and leaf was reduced under drought stress by controlling soil water content in root-extended period,vigorous growth stage and maturing stage.The content of soil relative water was 60%in root-extended period and vigorous growth stage,which had a promoting effect on root growth,thus increasing stress resistance of flue-cured tobacco.Because of local acidic soil,the deoxidize sugar content was 24.88%and the nitrogen-nicotine ratio was 1.05,which were both beyond the scope of quality standard of tobacco.The aroma and taste of tobacco leaf was influenced when the chemical composition was not harmonious.The content of deoxidize sugar reduced and the nicotine content increased under drought stress.When the soil water content reduced in vigorous growth stage and maturing stage,the yield,output value and rate of first-class decreased.This results showed that vigorous growth stage and maturing stage were the critical period to increasing yield and promoting quality.The yield,output value and rate of first-class were little influenced when the content of soil relative water was 60%in root-extended period.2.The chemical components of flue-cured tobacco was not harmonious under long-term drought stress.The deoxidize sugar content was 14.42%and the sugar-nicotine ratio was 7.1,which were both under the standard of high quality tobacco leaves.The physical properties such as leaf weight,leaf thickness,leaf area density,leaf tensile index were lower than those of normal tobacco leaf.The yield,output value,rate of first-class and neutral volatility aromas were also lower.The physical properties,chemical components and neutral volatility aromas were little influenced on filling water in root-extended period.Filling water in vigorous growth stage had a obvious promoting effect on yield and quality.The content of deoxidize sugar and potassium rose to the scope of high quality standard of tobacco.The physical properties such as leaf thickness,leaf density and tensile force increased.The stem ratio decreased.And the rate of first-class increased by 87%.The content of neutral volatility aromas rose to 1308.78?g/g.The yield and quality of flue-cured tobacco were also significantly improved by filling water on in maturing stage.And the content of neutral volatility aromas rose to 1315.31?g/g.In this paper,drought stress level and filling water in single growth period were regulated and controlled.The results of this study showed that drought environment in vigorous growth stage and maturing stage had the greatest influence on yield and quality of flue-cured tobacco.The same filling water in the two stages played an important role in the enhancement leaf production and the improvement of quality.