Effects Of Different Amount Of Magnesium Fertilizer On Growth Of Flue-cured Tobacco,Yield And Quality Of Tobacco Leaves

In order to promote the growth of flue-cured tobacco and improve the quality of tobacco leaves,Yunyan 87 was used as the test material to study the effects of different amount of magnesium fertilizer(0;125;250;375;500 kg/hm~2,representative by CK;A;B;C;D,respectively)on growth,yield and quality of flue-cured tobacco.The main finding are as follows:The application of magnesium fertilizer could promoted the growth and development of flue-cured tobacco,and improve the plant height,maximum leaf width,maximum leaf area,stem girth and leaf number of flue-cured tobacco;The value of SPAD and net photosynthetic rate of flue-cured tobacco were increased first and then decreased with the raised of magnesium fertilizer application amounts;The application of magnesium fertilizer could promoted the dry matter accumulation in each parts of flue-cured tobacco,while its mainly promoted the increase of root proportion dry matter of flue-cured tobacco,and regulated the dry matter transport in the organs of flue-cured tobacco,e.g.the dry matter was mainly promoted transport to the root of flue-cured tobacco in the high-speed growth period and budding stage,and the dry matter was gradually transferred to the leaves of flue-cured tobacco in ripe-period;The application of magnesium fertilizer could improved the resistance of mosaic virus and brown spot of flue-cured tobacco plant,and reduced the morbidity of disease and disease-infected indices.It was mainly affected the blade width and increased the leaf openness and the weight per leaf of upper leaves after baking,and also influenced the blade width,leaf openness and the leaf density of middle leaves after baking,but has little impacted on the other physical characteristics of tobacco leaves that the application of magnesium fertilizer;The application of magnesium fertilizer could improved the quality of tobacco leaves,reducing the content of nicotine in the upper leaves and regulating the content of chlorine and potassium,and promoting the total sugar,reducing sugar,total nitrogen,sugar nicotine ratio,nitrogen nicotine ratio,and potassium chlorine ratio to be suitable of tobacco leaves after baking;The application of magnesium fertilizer could also significant increased the economic benefits of flue-cured tobacco leaves,but it has different affected on the different levels of magnesium fertilizer application that the effect of lower level(125 kg/hm~2)or higher level(375-500kg/hm~2)of magnesium fertilizer application on growth,yield and quality of flue-cured tobacco was not good enough.Therefore,comprehensive the growth of flue-cured tobacco,yield and quality of tobacco leaves,it was more suitable to promoted the growth of flue-cured tobacco and the dry matter accumulation,reducing diseases and improve the yield and quality of flue-cured tobacco that the magnesium fertilizer application in the medium level of 250 kg/hm~2.