Influence Of Different Potassium Application Measures On Potassium Accumulation And Quality Of Dark Sun-cured Tobacco

Field experiments were conducted with local main variety(Dayehuang)in Nongan,Changchun,in the year 2014-2015.Experiments researched the effects of different types of potassium fertilizer,the amount of potassium fertilizer and the methods of application on growth characteristics of red sun-cured tobacco,availability of nutrient in the soil and the quality of tobacco leaves.The main research results are as follows:1.The effects of types of potassium fertilizer on potassium concentration and quality of the red sun-cured tobacco.(1)Studies have shown that different types of potassium fertilizer had a significant effect on soil pH and nutrient concentration.Biological potassium fertilizer and potassium humate could significantly reduce rhizosphere soil pH,and biological potassium fertilizer decreased greatly.Biological potassium fertilizer and potassium humate could activate the potassium in the rhizosphere soil,significantly improve the available potassium and slowly available potassium concentration in the rhizosphere soil.Biological potassium fertilizer and potassium humate could promote the improvement of available nitrogen in the latter part of the field.Potassium humate could reduce concentration of available sulfur in rhizosphere soil in the middle and latter part.(2)Biological potassium fertilizer and potassium humate could significantly increase the amount of dry matter accumulation,make the chemical fertilizer have better efficiency,improve the soil,promote root to grow fast,promote the formation and degradation of chlorophyll,and then improve the quality of tobacco leaves.Biological potassium fertilizer could significantly increase the activity of carbon and nitrogen metabolism of tobacco plants,increase the intensity of carbon and nitrogen metabolism,and then promote the formation of the blade containing substances in the tobacco leaves.Biological potassium fertilizer and potassium humate could improve the potassium concentration in the tobacco.Potassium concentration in each growth stage showed lower leaf> middle leaf> upper leaves,which indicated potassium nutrition was normal.Potassium humate was conducive to increasing potassium accumulation in the early growth of tobacco plant,while biological potassiumfertilizer was beneficial to increasing potassium accumulation in the late growth of tobacco plant.(3)Biological potassium fertilizer and potassium humate could improve the quality of tobacco leaves.Biological potassium fertilizer made the chemical composition of tobacco leaves more concerted that the concentration of total sugar and reducing sugar was high and the concentration of nicotine was lower.With biological potassium fertilizer,organic sylvite index was higher,and combustibility was better.It made leaf area,filling power,leaf weight and sensory quality better.With potassium humate,the concentration of aroma matter was highest,and the ratio of first-class tobacco and yield per mu were most.In general,considering the cost,with the biological potassium fertilizer,the effects were the best,followed by with the potassium humate.2.The effects of the amount and the application methods of potassium fertilizer on potassium accumulation and quality of the red sun-cured tobacco.(1)The application of potassium fertilizer could promote the growth and development of tobacco plants.The tobacco of treatments of applying potassium fertilizer had more dry matter accumulation than the control.When the ratio of N and K was 1:4(amount of 270 kg / hm~2),the tobacco plants had more dry matter accumulation than the ratio of 1:3.When potassium sulphate was used as topdressing on the day of 45 days after transplanting,the tobacco plants had more dry matter accumulation than the day of 30 days after transplanting.Tobacco leaves of the treatment T6 had the highest concentration and degradation rate of chlorophyll in the growth that the ratio of N and K was 1:4 and potassium sulphate was used as topdressing on the day of 45 days after transplanting.(2)The application of potassium fertilizer could the potassium concentration in the leaves and stems,and the potassium accumulation in tobacco leaves.When the ratio of N and K was 1:4,soil had strong ability to apply potassium,the potassium nutrition was in good condition,and the potassium concentration in the tobacco plants was high and the sulfur concentration at maturity was low.Potassium sulphate used as topdressing(T5 ? T6)helped to improve the potassium concentration in leaves.With the increasing amount of potassium fertilizer,the amount of potassium accumulation in the tobacco leaves was improved gradually.In maturity period,the amount of potassium accumulation showed the treatments that ratio of N and K was 1:4 had higher than the ones that ratio of N and K was 1:3.And both potassium levelsexpressed that topdressing on the day of 45 days after transplanting(T3,T6)had higher accumulation of potassium.(3)The application of potassium fertilizer helped to improve the quality of tobacco leaves after sun-cured process.From the view of the level of potassium fertilizer application,when the ratio of N and K was 1:4,the chemical composition of tobacco leaves was coordinate that the concentration of total sugar and reducing sugar in middle leavea was higher and the concentration of total nitrogen and nicotine was lower;the physical characteristics of the indicators were superior that leaves length,leaves width,leaves area and filling value were higher,and stem ratio was lower;neutral aroma components,output and value were higher,but the amount of potassium fertilizer in leaf had not a clear effect on the basic aroma in upper leaves.From the view of the methods of potassium fertilizer application,the chemical composition was coordinate that the concentration of total sugar was higher and the concentration of nicotine in middle leaves was lower.When the ratio of N and K was1:3,topdressing on the day of 45 days after transplanting helped to improve physical properties,neutral aroma components and sensory quality.When the ratio of N and K was 1:4,the difference between treatments(T5,T6)was insignificant,but they were better than basal application(T4).It was more conducive to the improvement of the alkaline aroma substance that potassium sulphate was used as topdressing topdressing on the day of 30 days after transplanting.