Study On Cropping System Improvement Of Tobacco Production Area In Liu-Yang

Through experiment of different crop rotation patterns such as tobacco-rice,tobacco-soybean and tobacco-corn, differences of yield and output value of thepatterns and changes of soil fertility and later tobacco leaf quality were studied.Some soil factors influencing tobacco leaf quality and their regulation methodswere also investigated. The results are as follows:1. Rice-tobacco rotation inhibited diseases and insect pests in tobaccoproduction fields in some extent. Adaptation of the system for long time and inlarge scale, however, would lead the ecological environment of the field becomingfragile and the soil physical and chemical features becoming unfavorable. Return ofrice straw helped improving soil structure and fertility.2. On fields of long time tobacco-rice cultivation, after two year continuousupland crop cultivation and first year tobacco-rice with rice straw returned to thefields and the second year upland crop cultivation, the soil bulk gravity decreasedand porosity increased. Total N, P and K contents in the soil were improved andeven better with rice straw returned to the fields.3. Application of tobacco-soybean rotation system in dry areas is a way ofincreasing cropping index, making better use of natural resources and improvingsoil fertility. In those areas with well irrigation it is recommended to adopttobacco-soybean one year and tobacco-rice the other year in turns to improve soilstructure, fertility and tobacco leaf quality effectively.4. It should not be applied of any single rotation system for long time and inlarge scale to avoid their negative influence on soil and crop production. Optimumcropping system is, depend on local natural condition, to adopt different patternsalternatively so to produce the best ecological, social and economical benefits.