Effects Of Bio-organic Fertilizer On Quality Of Flue-cured Tobacco In East Of Gansu Province And Its Mechanisms

Low content of the main chemical components(MCC) and neutral aroma components (NAC),lack of aroma and flavor,and the decline in commodity characteristics caused by long-time continuous cropping and irrational fertilization have been the serious problems in flue-cured tobacco production in east of Gansu Province. A field experiment was carried out in Zhengning County in Gansu Province in 2009 in order to study the effects of bio-organic fertilizer (BIO) application on chemical and aromatic qualities of Flue-cured Tobacco in East of Gansu Province and its preliminary echanisms. The results shown that:Chemical quality of flue-cured tobacco was proved with applying bio-organic fertilizer,the contents of potassium and nicotine and total soluble saccharides and reducing sugar within tobacco leaves were increased significantly,the ratio between total soluble saccharides and protein trended more to normal and measured up to the standard of high quality tobacco leaves. the content of potassium in upper leaves,middle leaves and bottom leaves were increased by 30.20%,26.30% and 50.50% respectively compared with CK and nicotine by 42.67%,28.50%,99.11% and 20.38% respectively. Application of BIO reduced the difference value between total soluble saccharides and reducing sugar and the ratio between total soluble saccharides and protein at different positions of tobacco leaves trended to the suitable range at the same time.BIO reduced pH value of tobacco-planting soil by 0.06 unit compared with CK and enhanced soil fertility Simultaneously. the content of organic matter and available nitrogen and available phosphrous and available potassium in soil were significantly increased by 30.25%,28.50%,104.57% and 7.80% respectively.?Meanwhile,application of BIO significantly affectd the microbial diversity in soil planted flue-cured tobacco and reduced the ratio between fungi and bacteria,those could bring about soil being in the state of more health. Namely,enhancement of soil fertility and biological features was the foundation that BIO could prove chemical qualitiy of Flue-cured Tobacco. Application of bio-organic fertilizer obviously promoted the growth and development of flue-cured tobacco and increased the content of chlorophyll in tobacco leaves during the whole growth period,In addition,the number and biomass and area of tobacco leaves in later developmental stage were increased by different extent,which could improve the canopied photosynthetic characteristics and photosynthetic productivity and were good for dry-matter production and sugar accumulation.Compared with CK,the nitrogen and potassium accumulation amounts of BIO treatment were obviously higher than CK in later developmental stage,at the same time,BIO affected nitrogen and potassium distribution in different organs and more nutrients flowed to tobacco leaves,which were the?major cause why the contents of nitrogen and nicotine and potassium within tobacco leaves under BIO treatment were obviously higher than those of CK.BIO significantly proved physiological activity of tobacco roots and increased ability of absorbing mineral nutrients in root. Compared with CK,oxidizing ability of root and activity of root system under BIO treatment were increased by 22.27% and 9.76% respectively.BIO significantly increased the total content of NAC in tobacco leaves by 26.79% -134.33% compared with CK. The total content of NAC at different position of tobacco leaves had dramatically different reaction to BIO,namely,the biggest increase was observed in the upper leaves,and the total content of NAC in upper leaves,middle leaves and bottom leaves were increased by 134.33%,81.03% and 26.79% respectively compared with CK. BIO application also changed the orders of the total content of NAC in tobacco leaves at different positions,the order of upper leaves>bottom leaves>middle leaves in CK treatment were turned into upper leaves>middle leaves>bottom leaves in BIO treatment, which is favorable to the output value of tobacco production. The main NAC in tobacco leaves in Zhengning is neophytadiene , accounting for 79.67%-89.43% of the total amount. The neophytadiene content in upper,middle and bottom leaves of BIO treatment were increased significantly by 157.33%,88.15% and 31.17% respectively compared with CK. BIO improved the nitrogen absorption by tobacco,which not only increased the chlorophyll content in tobacco leaves,the precursor of neophytadiene,but postponed the summit of chlorophyll content by about 15 days as well which could extend the mature period. Activities of invertase and nitrate reductase at round top stage in BIO treatment were increased by 30.02% and 13.42% compared with CK,which contributed to the dry matter accumulation,nitrogen uptake,as well as to the synthesis of NAC and chlorophyll.