Research And Demonstratiton Of The Key Techniques In High Quality And High Efficiency Production Of Flue-cured Tobacco In Jiahe County

Jiahe county is one of the main tobacco production districts in Hunan,the tobacco quality is rather fine,but there exists following problems:the maturing degree of tobacco is not sufficient,the percent of green tobacco after baking is big,the nicotine content is a little bit higher,the usableness is not good enough.So,exploring and establishing an integrated technique standardization is very important for increasing tobacco quality,satisfing the need of industry for tobacco material,realizing sustainable development of tobacco production in Jiahe county,increasing the income of farmers, and increasing national revenue and company's economical profit.To the question of key techniques in tobacco production of Jiahe county,the following researches were conducted:(1) screening out tobacco varieties adaptable for local conditions;(2) developing better seedling raising methods to foster sturdy seedlings;(3) determining the best fertiliser amount and the proportion of N:P:K;(4) studing and determining the best transplanting date and partern;(5 fixing on the best unveiling time of plastic film in tobacco fields.On the base of reserches,the integrated techniques for high quality and high efficiency tobacco production were assembled and demonstrated.The results were as follows:1.Selecting suitable variety is the basis for fine quality tobacco production in Jiahe. Taking yield,production value,the ratio of fine and middle class leaves and the resistance to diseases and adversity as judging indexes,the variety "Yunyan 87" is the best,followed by "Yunyan 85" and "K326".2.Floating seedling raising with plastic pond is the best method,with obvious advantages in keeping water temprature,promoting seed germination and seedling quality.As for the cost,one-off cost of plastic pond is higher,but plastic pond can be successively used for over 3 years,so the yearly cost is similar to brick pond and earth pond.3.The suitable fertilizing amount is 142.5-157.5 kg/hm²,under the fertilization of 157.5 kg/hm² with pure N,the yield,production value and the percent of fine tobacco leaves were all higher,the agronomic characters were the best,followed by the treatment of 142.5 kg/hm²,120kg/hm² is the worst treatment.As for the appearance and internal quality of tobacco leaves,the treatment with 157.5 kg/hm² N application was the best,behaving as bisque in leaves colour,moderate in leaves thickness,loosen in tissue structure,sufficient aroma and fine fragrant,comfortable residual flavour,good combustibility,white ash,and harmonious in the main chemical components.4.The optimal transplanting duration is from 1^st March to 20^th March.The vigorous growth duration,maturing duration and whole growth duration were the longest in the treatment of transplanting on 1^st March,with optimal biologic characters, more assimilate accumulation,sufficient maturing degree and higher yield and quality. It was better to transplant on 8^th March and 15^th March than on 22^nd March and 29^th March.5.As for cultivation with plastic film mulch in tobacco fields,the optimal time for film unveiling was at 35-40 d after transplanting.Under the same cultivation condition, the treatment with unveiling film at 35 d after transplanting was best,with more leaves number,larger leaf area,higher production value and fine class leaf ratio,followed by the treatment with unveiling film at 50 d after transplanting.The treatment which cover plastic film during whole growth duration is the worst.6.From 2005 to 2008,13497.9 t of leaf tobacco has been purchased with the average price of 11.14 yuan/kg and 150.42 million yuan of the total output value. Compared with conventional production technology,the per unit area yield was increased by 102 kg/hm²,the total yield was increased by 623672kg,the ratio of fine class leaf was increased by 11.76%,certified rate of tobacco leaf was up to 86%,output value was increased by 3360 yuan/hm²,total output value of Jahe county was increased 20.5 milliom yuan,net output value was increased 17.79 million yuan,the tax from tobacco production was increased by 4.1 million yuan,the profit of tobacco company was increased 22.4 million yuan.