Comparative Study On Multiple Cropping Patterns Of Tobacco In Hunan Province

Tobacco is one of the most important economic crops in Hunan Province. Since single cropping in dry land and tobacco-rice multiple cropping have been the main tobacco cropping pattern for a long time, defects of tobacco continuously cropping pattern emerge gradually, which is a potential threat to the tobacco sustainable development. Therefore, it is necessary to study and screen out the new and suitable tobacco cropping patterns.Systematic investigation and field experiments in the main tobacco production areas in Hunan province were carried out in order to prove up the advantages and disadvantages of different tobacco cropping patterns, to analyse the existing problems, to select the suitable tobacco cropping pattern which could gain high economic and ecological benefits and adapts to actual situation of Hunan province, and finally provide theoretical basis for the most appropriate way of farming systems and multiple cropping to contribute tobacco sustainable development.The main results are as follows:1. Through survey in Hunan province, it was found that in the same planting conditions, the yield, production value and total income of the tobacco-rice multiple cropping were much higher than that of other planting patterns. However, due to the hysteresis of prices adjustment of tobacco, the comparative benefits predominance of tobacco gradually reduce in compare with the major food crops and other economic crops, and coupled with the significantly increasing of the price of production materials and employment year after year, the costs of flue-cured tobacco production increased gradually. Moreover, tobacco production is labor-cost and labor-intensive, the development of flue-cured tobacco is facing severe short of laborers.2. Through the settled field experiment on four different cropping patterns: tobacco-rice, tobacco-rice-green manure, tobacco-corn and tobacco-rice-vegetable in three years, it was found that tobacco - rice - vegetables can significantly improve the agronomic characters of tobacco, and the contents of protein and nicotine in flue-cured tobacco were suitable, the content of potassium was the highest, and the proportion of the first-class tobacco and production output were significantly higher than that of other cropping patterns, the quality of tobacco was ideal. Furthermore, tobacco - rice - vegetable cultivation model can effectively prevent the occurrence of tobacco bacterial wilt disease and Brown spot disease, reduce pesticide use and manpower expenditure, consequently improve the income. It is worthy of popularizing in tobacco paddy fields.3. Through the settled field experiment on four different dryland cropping patterns of flue-cured tobacco: tobacco / sweet potato- ryegrass, wheat / tobacco, tobacco / sweet potato and wheat / tobacco / sweet potato in three consecutive years, it was found that the cropping pattern of wheat / tobacco / sweet potato can significantly improve the agronomic characters of tobacco, and the contents of protein and nicotine in flue-cured tobacco were suitable, the potassium content is the highest, and the proportion of the first-class tobacco, yield and production value were significantly higher than that of other cropping patterns, the quality of tobacco is ideal. It is worthy of popularizing in dryland.