Study On Influence Of Main Ecological Factors On Flue-cured Tobacco Upper Leaves And It's Improvement Techniques In Kunmng

The low usability of flue-cured tobacco upper leaves is one problem of tobacco industry in China.At present,because of advocating a reduction of tar in the tobacco industry,it is a great meaning of improving the flue-cured tobacco upper leaves' s usability on the quality and quantity of flue-cured tobacco in general.The research did a comprehensive analysis on the upper leaves characteristics and usability of flue-cured tobacco in KunMing tobacco-growing area,and provide technical methods of improving usability of KunMing flue-cured tobacco upper leaves,considering effects of the regional climate and soil characteristics on flue-cured tobacco upper leaves.The main results were as follows:1.Analysis on quality characteristics and availability of KunMing flue-cured tobacco upper leaves.There were some degree of regional differences in appearance quality,physical indicators,chemical composition,sensory quality and comprehensive assessment results of KunMing flue-cured tobacco upper leaves.Mean score of appearance quality of the KunMing flue-cured tobacco upper leaves was 84.87,most of the regional tobacco upper leaves appearance quality score was generally good;Mean score of tobacco upper leaves physical qulity was 79.35,most of the regional tobacco upper leaves physical quality score was generally good too;Mean score of tobacco upper leaves chemical quality was 70.55,and most of the regional tobacco upper leaves chemical quality score was moderate;Mean score of tobacco sensory quality was 72.86,and most of the regional tobacco upper leaves sensory quality score was moderate too.As a whole,mean score of KunMing tobacco was 73.46,most of the regional tobacco upper leaves was moderate.2.Climatic and soil characteristics in KunMing tobacco-growing area and their effects on quality of tobacco upper leaves.The study had evaluated the climate factors of the flue-cured tobacco in nine counties in KunMing from 2012 to 2015 to determine suitability,and had clarified the averagetemperature in root extending period,vigorous growing period and mature period was in the optimum range of the growth of flue-cured tobacco.In addition,the climate suitability index in KunMing tobacco-growing area was relatively high,and climate conditions were proper,which was suitable for producing high quality tobacco.Because the quality of the upper leaves of the cured tobacco was mainly formed in the maturation of the field,changes of ecological factors were the key to determine the quality of upper leaves.Through simple correlation analysis between climate factors at all times and appearance quality,physical indicators,chemical composition,sensory quality in every tobacco-growing area of KunMing,it was found out that average temperature of mature period had a significant positive correlation with most quality characteristics of upper leaves,while rainfall in mature period had a negative correlation with partial quality characteristics.This indicated that higher temperature in mature period benefited quality of upper leaves and improvements of usability,while excessive rainfall in mature period limited them.Soil nutrient of different districts in KunMing tobacco-growing area had a great influence on quality of tobacco upper leaves.In appearance quality,alkali-hydrolyzable nitrogen had a significant effect on tobacco leaf structure,maturity,identity,oil content and colour.In physical property,Soil organic matter content and total potassium had a large effect on tobacco leaves,the main indices included single leaf weight,leaf length,open slice and foliage density.In chemical component,potassium content and nitrogen-nicotine ratio in tobacco leaves were less affected by soil nutrient content,the numerical differences were not significant,while contents of other chemical composition were significantly affected by soil nutrient content.In sensory quality,soil organic matter conetent,total nitrogen and alkali-hydrolyzable nitrogen had a great influence.3.Researches on improving the usability of the upper leaves of the flue-cured tobacco and it's new exploration of evaluation method.(1)On the study of the influence of organic inorganic compound fertilizer on the quality improvement of the upper leaf tobacco,it is found that when organic fertilizer accounted for1/3-1/2,the reduction in tabacco production was not obvious,the scale of average price and middle-upper of tabcco were the highest,and the potassium of the leaves increased,which raised the upper leaves quality.Therefore,when applying organic and inorganic fertilizer,the proportion of organic fertilizer was supposed not exceed 1/2.(2)The study on the effectsof the density of cultivation and the amount of nitrogen on upper flue-cured tobacco leaves indicated that,the best quatity of tobacco upper leaves in SongMing area was by the way with transplanting density of 1.1 m×0.50 m,and applicating nitrogen of 6.5 kg-8kg per acre.(3)The study on the effects of young seeding transplant of film cultevation on upper tobacco leaves indicated that,the tobacco survival rate of this technology was higher,and tobacco harvesting time was 12 days in ahead,and the sensory quality was slightly better than the conventional one.(4)The study on the effect of harvesting methods and maturity on the structure and quality of tobacco upper leaf cells indicated that,the upper leaves after been transplated for 125 days had loose structure,more accumulation of organic matter and sensory assessment scores were superior to those in other periods.Therefore,the best havesting period in SongMing tobacco growing area is 125 days after tobacco seedling transplanting.(5)The study on the relations of softness and quality of KunMing tobacco upper leaves indicated that,the softness value of good softness tobacco upper leaves was less than 40 mN,and the bad one was greater than 60 mN.The appearance quality scores,sensory quality scores and main chemical components harmony of good softness tobacco upper leaves were obviously higher than the bad ones.The good softness tobacco upper leaves had looser cell structure,bigger intercellular space and thickness ratio of spongy tissue and palisade tissue was equal and greater than 1.