Study On Harvesting Techniques For The Improvement On Usability Of The Upper Flue-Cured Tobacco Leaf In Southern Hunan

For improving the usability of thick aroma type upper leaves of main production area in Southern Hunan, improving the maturity of upper leaves as the core, pots experiments (Comparative study on the comprehensive effect of harvesting methods of upper leaves; Study on the suitable field-maturity of upper leaves concentration harvested; Comparative studied on the adaptability of concentration harvesting of different tobacco varieties) were carried in Guiyang county, Chenzhou in the years of 2009 to 2010, aim to explore the mature Harvesting techniques suite to the leading varieties of the thick aroma type flue-cured tobacco main production area in Southern Hunan, the main conclusions were as follows:1. Comparing with common harvesting method, the appearance quality, physical properties, chemical composition and economic properties of the upper leaves of flue-cured tobacco concentration harvested and harvesting with stalk were all certain advantages. The methods harvested the upper 6 leaves in one-time all can reduce the times of tobacco harvesting, remit the contradiction of flue-cured tobacco harvesting and other farm work strive for the farm labor in the "Robbery and Snatching" season, but the method concentration harvesting was the best one due to the overall quality of upper leaf.2. Appropriately delay of the harvesting time was helpful to improve the overall quality of the upper leaves, there-among, the upper leaves (The leaves mainly with yellow, midrib whiten above 70% and lateral vein whiten around 50%; stem-leaf angle was close to 90 degrees, had more mature spot)harvested with 15 days extended, the various index of flue-cured upper leaves of comprehensive performance was the best, but the upper leaves (the leaves filled with yellow, all leaf vein turned white, stem leaf angle was bigger than 90 degrees, part of leaf tips and margins has obvious phenomenon of scorched) harvested with lengthen 20 days or so, would adverse impact the flue-cured tobacco yield and quality.3. To compare the effects of the different varieties of flue-cured tobacco from concentration harvest, the effects come from concentration harvest to the Yun87 and Yue97 were obviously better than the K326, but the upper leaves maturity, oil and leaf density compared in different tobacco varieties, the K326 variety was the best. The comprehensive adaptability effects of concentration harvesting of different flue-cured tobacco were:Yun87≥Yue97> K326.4. Although the quality of upper leaves could get a certain extent improve through concentration harvest upper 6 leaves and moderate extend its harvest time, as the harvesting time delay, the yield and output of the upper leaves will get a different decrease. Especially in the Tobacco-Rice rotation area in Southern Hunan, postponed harvesting will greatly influence the seeding and transplanting of succeeding crops (rice), further impact on the earnings of farmers. The feasibility of concentration harvesting and extend the upper leaves harvesting time were better to early-maturing flue-cured tobacco variety.