Study On The Effects Of Rice Straw Returning On Growth And Quality Of Flue-cured Tobacco

Conservative tillage and cultivation in cropland is an important way to sustainable agriculture development. Straw returning thechnology is an important measure of Conservative tillage and cultivation technology. Tobacco is an important economic crop in China. Tobacco industry is not only the leading industry of breaking away from poverty but also the primary resource of finance and revenue in tobacco-planting regions of Hunan. Since 80's of 20 century, tabacco-rice sequential cropping system has been practised and effectively promoted the development of tabacco production in south China. Nowadays, tabacco-rice sequential cropping system is very popular in tabacco planting area of south China. Because of the abundant rice straw resources, it is very important to study the effects of rice straw returning on tabacco growth and quality in order to achieve a sustainable development of tabacco prodution with fine quality, suitable yield and high efficiency. Whereas, the effects of rice straw mulching, straw returning methods, straw returning quantity were compared. The results are as follows:1.Rice straw mulching in tobacco planting field can regulate the soil temperature in the whole growth and development stage of tobacco, increasing soil temperature under cold and decreasing soil temperature under warmer weather. And it has obvious effect on water sluice and reservation in soil, especially in drought season. The effect of the treatment with 500kg/667m~2 straw returning is better than that of 300kg/667m~2 straw returning treatment.2. There have no significant difference in dry matter production among straw mulching treatments, straw deep incorporation treatment and CK at knee-high stage of tobacco growth. At vigorous growth, budding stage and mature stage, the dry matter accumulation all indicate that full straw returning treatment prior to half straw returning treatment, and half straw returning treatment prior to CK. 3. The yield, production value, proportion of high grade leaves and average leaf prices in rice straw deep incorporation treatment were the highest.4. Total sugar, reductive sugar, Cl, K content of flue-cured tobacco leaf were all increased under straw mulch and straw deep incorporation treatments. The effects of full straw returning treatment were bigger than that of half straw returning treatment. There was no significant difference in N and Mg content among different treatments and CK. Nicotine content of deep incorporation treatment was obvious higher than that of CK. There was no significant difference in nicotine content between straw mulching treatment and CK treatment. The content of nicotine was increasing while the quantity of straw returning increasing. The chemical component of flue-cured tobacco under straw mulch and straw deep incorporation treatment was piror to CK treatment.