Effects of Returning Rice Straw to Field plus Applying Decomposition Agent for Consecutive Two Years on Soil Characters of Continuous Cropping Tobacco Field,and Yield and Quality of Flue-cured Tobacco

The location tests for returning rice straw to field plus applying decomposition agent were carried out in multi-year tobacco-rice rotating tobacco field in Changting county during 2011 ~ 2012. The results indicated that continuously returning rice straw to field had obvious influences on the soil characters of tobacco field,as well as the yield and quality of flue-cured tobacco. The soil bulk density,organic matter content,total nitrogen content and available potassium content changed very significantly after returning rice straw to field. Returning rice straw to field promoted the growth of tobacco plants,and improved the disease resistance of tobacco plants. The 2-year average tobacco leaf yield in treatment 3( returning rice straw to field plus applying decomposition agent) and treatment 2( directly returning rice straw to field) was respectively 9. 0% and 6. 4% higher than that in treatment 1( no returning rice straw to field),and the 2-year average production value of flue-cured tobacco was also 13. 6% and 10. 1% higher respectively. So returning rice straw to field had significant yield-increasing and income-increasing effects,and the effects in the second year were larger than those in the first year. After returning rice straw to field,the contents of inherent chemical compositions in tobacco leaves were in a suitable range,and the proportion of middle-high-class tobacco leaves was above 90%.