Influences of Different Topdressing Levels of Potassium on the Yield and Quality and Tar Content in Flue-cured Tobacco

[Objective] The purpose was to study the influences of different topdressing levels of potassium on the yield and quality and tar content in flue-cured tobacco K326.[Method] The randomized block arrangement was used in the experiment,in which 4 treatments A,B,C and D(topdressing no potassium fertilizer,topdressing 120,240 and 360 kg potassium fertilizer) were set up.[Result] During vigorous growth stage,plant heights in treatments C and D were increased by 25.14% and 23.91% resp.in comparison with treatment A and their pitches were 2.91 and 2.94 cm resp.The stem thickness and available leaf number in treatment D were 9.14 cm and 18.20.During maturing stage,the plant height,pitch and stem thickness in treatment B were increased by 6.38%,28.57% and 6.26% resp.in comparison with treatment A.Compared with treatment A,the yield values and yields in treatments B,C and D were increased by 5.58%,6.79%,3.96% and 43.3-62.3 kg/hm2 resp.,the nicotine content in treatment C,which was 2.33%,was decreased by 25.75%.The contents of water-soluble total sugar,reducing sugar and potassium in treatment D were 25.61%,21.85% and 2.25% resp.Compared with A,the tar contents in treatments B,C and D,with average value of 6.9%,were decreased by 2.17,4.80,5.93 mg/g resp.[Conclusion] Topdressing sulphate potassium had significant influences on the growth and development,yield and quality of flue-cured tobacco and the contents of main components in tobacco leaf and its smoke.