Abstract:

To study the effects of spraying different potassium fertilizers on yield and quality of flue-cured tobacco, a flue-cured tobacco cultivar ‘Honghuadajinyuan’ was used as experimental material, single factor randomized block design was adopted. Three kinds of potassium fertilizers, potassium sulfate fertilizer, potassium dihydrogen phosphate fertilizer and organic potassium fertilizer, were sprayed on the leaves of tobacco plants at three stages of resettling stage, fast-growing stage and squaring stage, respectively. The results showed that spraying potassium fertilizers could improve the plant height, stem girth, effective leaf number and so on. All treatments had good economic benefits and the organic potassium (treatment T2) was the best one. The yield was 2115 kg/hm ² and the output value was 45582 yuan/hm ². Spraying potassium sulfate fertilizer increased the ratio of fine and middle-grade tobacco by 67.7%. Spraying potassium fertilizer on leaves could increase potassium content and decrease nicotine content in tobacco leaves. In addition, potassium sulfate (treatment T1) could increase the content of reducing sugar and total sugar in upper tobacco leaves up to the required content range of high quality flue-cured tobacco, and the performance of sugar-nicotine ratio and reducing sugar-total sugar ratio was better than that of other treatments. The results showed that the use of potassium sulfate fertilizer in resettling stage, fast-growing stage and squaring stage was more suitable for the variety ‘Honghuadajinyuan’ and obviously affected the coordination of chemical components in tobacco leaves.

Key words: flue-cured tobacco, potassium fertilizer, spraying on leaves, tobacco leaf quality.