Effect Of Nitrogen Application Rates And N And K Fertilizer Applied Methods On Soil Inorganic Nitrogen Content、 Flue-cured Tobacco Growth And Quality

Within the situation that nitrogen fertilization improperly provided and nitrogen,potassium provided by fertilization technology in tobacco production does not matchwith nitrogen and potassium required in tobacco growth process, this paperresearched the effect of nitrogen application rates and N and K fertilizer appliedmethods on agronomic characters, inorganic nitrogen content, nitrogen accumulation,chemical components, aroma components content and economic benefits by fieldexperiment.Effect of nitrogen application rates on soil inorganic nitrogen content、flue-curedtobacco growth and quality experiment showed that:(1) Nitrogen in the range of0~52.5kg/hm2each agronomic character inresettling stage, vigorous growth stage and the round top stage increased with the Napplication rates increase. when nitrogen rate reached67.5kg/hm2, agronomiccharacters improved not obviously and had a negative effect on normal falling yellow.(2)0~20cm layer soil NO3--N and NH4+-N content increased with the Nappication rates increase before11thand9thweeks after transplanting.20~40cmlayer soil NO3--N less affected by N appication rates; NH4+-N content was affected byN appication rates before9thweeks after transplanting. The influence of the soilinorganic nitrogen was not obviously in40~60cm soil layer.(3) Nitrogen accumulation increased with the nitrogen application ratesincrease before13thweeks after transplanting. Nitrogen accumulation in differentorgans showed that: leaf> stem> root. Different leaf position was showed that:middle leaf> upper leaf> lower leaf before11thafter transplanting; then upper leaves> middle leaves> lower leaves.(4) Nitrogen fertilizer could significantly improve flue-cured tobacco total sugarand reducing sugar content, and the content increased with the increase of the Napplication rates. Too much nitrogen fertilizer (Nitrogen application content was67.5 kg/hm2) improved nicotine and total nitrogen content, while reduced potassiumcontent. From sugar/alkali ratio, nitrogen/alkali ratio and K/Cl ratio respects,tobacco leaf chemical components of52.5kg/hm2treatment was closer to the standardof quality tobacco.(5) Browing reactions and Cembratriendiol content were increased with Napplication rates increased. The treatment of N application rate67.5kg/hm2washighest. Phenylalaninc, carotenoids, neoplytadiene content and the total aromaamount were highest in52.5kg/hm2nitrogen treatment. Correlation analysis showdthat applied nitrogen content and neutral aroma substances amount highly correlated.There was a highly significant positive correlation between N application rates andaverage price, the proportion of superior tobacco leaves, yield, output value. Thecorrelation between N application rates and yield was maximum and significant at the0.01level. At the local ecological conditions, economic benefits and nitrogenfertilizer use efficiency was highest at the52.5kg/hm2nitrogen level.Effect of N and K fertilizer applied methods on soil inorganic nitrogen content、flue-cured tobacco growth and quality experiment showed that:(1) Adequate basal fertilizer contributed to tobacco grouping in inresettling stage,diluted potassium nitrate could significantly improve flue-cured tobacco agronomiccharacters and the promote upper leaves opening. But topdressing ratio too much wasnot conducive to tobacco normal falling yellow. In all respects, the treatment of baseand topdressing ratio was7/3, and all potassium nitrate diluted separately for threetimes during the vigorous growth stage was most effective and could significantlyincrease the K content in the middle and upper leaf, and made tobacco sugar/nicotineratio and K/Cl ratio tend to be coordinated, and so could improve the upper leafusability.(2) The inorganic nitrogen content in0~20cm soil layer increased with theincrease of topdressing proportion during7th~11thweeks after tobacco transplanting.Potassium nitrate diluted in vigorous growth stage and round top stage couldsignificantly increase NO3--N content in0~20cm soil layer, but it had no obviouslyinfluence on NH4+-N content behind13thweeks after tobacco transplanting.(3) Compared to other treatments, disposable fertilization treatment nitrogenaccumulation amount in each organ was relatively smaller. Potassium nitrate dilutedin vigorous growth stage and round top stage could significantly promote nitrogenaccumulation in leaves. Topdressing proportion of tobacco specialty fertilizer had a great influence on nitrogen accumulation and nitrogen accumulation increased withthe increase of topdressing proportion.(4) The treatment of base and top dressing ratio was7/3, and all potassiumnitrate diluted separately for three times during the vigorous growth stage not onlycould in favor of coordinating and balance chemical compositions of flue-curedtobacco leaves, increase aroma amount, but also increase production and improve theoutput value.