Effects of Amount of Rice Straw Returning to Field by Mulching on Temperature of Tobacco Field Soil,Growth and Development of Flue-cured Tobacco in Chenzhou,Hunan Province

For further extension of technique of rice straw returning to tobacco field,a field experiment was conducted in Chenzhou,Hunan in 2012 to study the effect of rice straw returning to field by mulching on temperature of soil,growth and development and yield traits of flue-cured tobacco. The results showed that soil temperature was affected by rice straw mulching,it showed decrease effect before mid-June and adjusting effect after middle decade of June. Rice straw mulching appreciably delayed the maturity of tobacco 1 ~ 2 d,improved agronomic characters of tobacco plants and the best effect was observed in treatment of rice straw 4000kg /hm2. Rice straw mulching improved the dry matter accumulation of tobacco plants after rapid growth stage and weight per leaf,length and width of middle and upper leaves. Rice straw mulching had no clear effect on weight per leaf,average price,medium and first-class leaf proportion,while improved the yield and output value of flue-cured tobacco and the best effect was observed in treatment of rice straw 4000kg /hm2.