Approriate Yield Levels And Yield Strcture Of Quality Fuii-flavor Flue-cured Tobacco In The Middle Of Henan Province

The middle of Henan Province is a typical producing area of full-flavorflue-cured tobacco. High quality and suitable yield would ensure obtaining doublebenefits of countries and famers. In order to determine the suitable production levelsand yield factors of typical full-flavor flue-cured tobacco, the trials associated withnitrogen application,density and remained leaves were conducted in XiangchengCounty, Xuchang City and Baofeng County, Pingdingshan City both of which weretypical representative of the middle of Henan Province from2010to2012. The mainresults were as follows:1. In the range from0to90kg/hm2, leaf length, leaf width, leaf area, weightper leaf, weight per unit leaf area were linear positively correlated to the amount ofapplied nitrogen. Both leaf thickness and stem ratio had quadratic relationships withnitrogen fertilizer amount. With the amount of nitrogen application increased, leafthickness first increased then decreased, while the stem ratio just behaved on thecontrary. Yield, output value, average price, price, proportion of superior tobacco leafwere all quadratic curvilinearly correlated with the amount of nitrogen application.The yield increased with the increase of nitrogen fertilizer level, while it was in agradually declining rate. The highest yield, highest average price and proportion ofsuperior tobacco leaf were respectively met when nitrogen amount were42.92kg/hm2,27.81kg/hm2,40.62kg/hm2（NC297）, and44.34kg/hm2,29.43kg/hm2,37.91kg/hm2（Yuyan5）. Both NC297and Yuyan5were quite compatible in chemical compositionwhen treated with nitrogen22.5kg/hm2and45kg/hm2respectively. The total contentof aroma components is highest when nitrogen amount were45kg/hm2. The mostsuitable nitrogen application range of NC297and Yuyan5was27.81⁴2.92kg/hm2and29.43⁴4.34kg/hm2respectively. The two varieties are nitrogen efficient at lownitrogen level. The promotion of cultivating these two varieties in the central ofHenan Province can help to reduce the wasting of resources and prevent environmentfrom pollution.2. It was indicated that leaf length, leaf width, leaf thickness, leaf area and singleleaf weight showed the same trend of increasing up with the nitrogen applied in the range of nitrogen application rate of7.5⁶0kg·hm^-2, while stem rate and dry weightper unit leaf area first decreased then increased. Moreover, as the nitrogen applied andremained leaves added, nicotine and total nitrogen content significantly increased anddropped down respectively. The yield of tobacco sustained to grow up in that range,while the output value, average price, proportion of superior and moderate tobacco allshowed the trend of decreasing after increased up. As to physical characteristics,chemical compositions, chemical indexes and economic characters, all the indexesaside from reducing sugar and sugar/nicotine ratio displayed the order of F value thatnitrogen application> remained leaves> interaction. According to the study, theappropriate nitrogen amount and remained leaves were30kg·hm^-2and20²3,respectively.3. The results show that the effect of row spacing on yield level was negative,and the effect of nitrogen application and remained leaves on the yield level werepositive. The ranking order from high to low of Influence on yield level was nitrogenapplication, harvestable leaves, row space, and in their influence, direct effectoccupied the main role, indirect effect is small. Aroma quality, aroma volume, totalscore, output value, average price and proportion of superior and moderate tobacco allhad quadratic curves relationships with yield level. With the amount of yieldincreased, they all first increased then decreased. The optimum yield level in theMiddle of Henan Province was in the range of2550kg·hm^-2to2800kg·hm^-2.4. The most suitable weight per leaf range of upper leaves, cutters, lugs was13.12g¹5.27g,11.31¹3.29g,9.82¹1.75g respectively. The most suitable leaflength range of upper leaves, cutters, lugs was63.39⁷0.72cm,58.67⁶5.77cm,49.32⁵5.91cm respectively. The most suitable leaf width range of upper leaves,cutters, lugs was31.77³5.33cm,29.56³2.99cm,25.32²7.89cm respectively. Themost suitable leaf area range of upper leaves, cutters, lugs was1308.33¹637.88cm2,1258.33¹427.56cm2,836.11¹031.64cm2respectively. The most suitable leafthickness range of upper leaves, cutters, lugs was127.15¹39.59μm,103.94¹14.41μm,88.43⁹8.84μm, respectively.5. After grouping and sensory evaluation of tobacco leaf samples, the resultsshowed that all the samples can get a high score and the grouping samples can beconsidered as the represent of high quality flue-cured tobacco in the middle area ofHenan Province. Some index ranges of high-quality flue-cured tobacco have beenmeasured in the middle of Henan Province.The range of stem ratio was 22.69%³0.14%; the range of weight per unit leaf area was85.70g·m^-2111.84g·m^-2;the range of total sugar was21.29%²4.69%;the range of reducing sugar was15.35%²1.27%; the range of nicotine was2.05%².7%; the range of total nitrogenwas1.78%².36%; the range of potassium was1.16%¹.87%; the range of chlorinewas0.47%⁰.84%.