Studies On Effects Of Harvesting With Stem And Its Corresponding Techniques To Upper Leaves Usability Of The Flue-cured Tobacco

Experiments were conducted to study effects of different harvesting methods, maturity, numbers of leaves remained and languished time on nicotine, starch and chlorophyll content, economic properties and quality of K326, a variety of flue-cured tobacco, to improve the usability of upper leaves. The results were as follows:1. Leaf nicotine contents of all stalk positions under harvesting with stem, ripe, 5 leaves remained and languished 36h were the highest, while that in stem under leaf picking, ripe, 4 leaves remained and languished 36h were the highest. Stem nicotine contents had extremely remarkable negative correlation with last one,next but one,next but two and the mixture leaves. Stem nicotine contents had remarkable negative correlation with next but three. Nicotine in stem could transfer to leaves during flue curing.2. During the flue curing period, starch content of upper leaves reduced gradually. Leaf starch content under leaf picking decompounded most during 0-36h after flue curing began. While that under harvesting with stem decompounded most and lasted longer during 36-60h after flue curing began. Leaf starch content in harvesting with stem, ripe, 5 leaves remained and languished 36h was the lowest after flue curing.3. During the flue curing period, chlorophyll content of upper leaves reduced gradually. Leaf chlorophyll under harvesting with stem decompounded faster than that under leaf picking during 0-36h after flue curing began. Leaf chlorophyll content in harvesting with stem, ripe, 5 leaves remained and languished 36h was the lowest after flue curing.4. Output value, average price, ratio of high-quality leaf under harvesting with stem, ripe, 5 leaves remained and languished 36h were the highest and its harmonization of chemical components were the best.