Effect of Continuous and Multiple Cropping of Tobacco-Rice on Economic Attributes and Quality of Flue-cured Tobacco

In order to reveal the effect of continuous and multiple cropping of tobacco-rice for many years on the yield and quality of flue-cured tobacco, 20 of tobacco field for different continuous cropping years from three tobacco growing areas were investigated. Trend analysis and significant evaluation were carried out with each index. The results showed that it was in quadratic curve relationship between tobacco economic traits, main chemical composition and continuous and multiple cropping years during 1-23 years of tobacco-rice continuous and multiple cropping. Tobacco economic traits presented a downward trend after 12 years of tobacco-rice continuous and multiple cropping. The coordination of tobacco chemical composition declined gradually after 14 years. The major sensory quality of tobacco leaves decreased with years of tobacco-rice continuous and multiple cropping increasing. It suggests that in order to overcome adverse effect of continuous and multiple cropping on yield and quality of tobacco, the necessary crop rotation is required after continuous and multiple cropping for 10 years.