Effect Of Different Nitrogen Rates On Yield And Quality Of Flue-cured Tobacco In Xiangxi Mountains Region

In this study,through different fertilization treatments exploring the fertilization methods of tobacco scale cultivation in Xiangxi mountain.The main results are as follows:(1)Effects of different nitrogen rates on root system growth of tobacco plantAfter 75 days transplanting,the growth of tobacco plant achieved the maximum level,underground biomass of decreasing nitrogen was an average of 50.50 g,biomass of increasing nitrogen than decreasing nitrogen increased 44.8%,regular fertilization and increasing nitrogen were basically the same.Thus,reducing nitrogen significantly decreased the underground biomass accumulation of tobacco plant,increasing nitrogen promoted the underground biomass accumulation.By processing the root volume of adding nitrogen fertilizer was 296.67ml,increased by 14.1%compared to conventional fertilization,21.9%higher than the reducing nitrogen application.Reduction of nitrogen fertilizer significantly had a negative impact on tobacco root volume,but adding nitrogen fertilizer in the late growth stage still can effectively promote the tobacco root volume effect.Adding nitrogen fertilizer root shoot ratio increased by 7%compared with the conventional fertilization,promoted the ratio of root to shoot,contributed to the development of tobacco root system.(2)Effects of different nitrogen rates on the part of the tobacco plant on the groundThe treatment plant height of the reduced nitrogen fertilizer was reduced to 93.17cm,which was 12.1%lower than that of the conventional fertilization,and the plant height was significantly decreased,The treatment plant height of the increase nitrogen fertilizer was 3.4%higher than that of the conventional small,so the increase of nitrogen fertilizer did not significantly increase the plant height,conventional fertilization method can coordinate the stable growth of tobacco plant height.Increased application of nitrogen fertilizer on biomass accumulation than the conventional fertilization increased by 4.9%,while reducing the nitrogen than the conventional fertilization decreased by 4.7%,and therefore,increasing nitrogenous fertilizer could significantly increase the part of the biomass accumulation of the strains of tobacco growth development have a positive effect,reducing the nitrogen application significantly reduced the accumulation of biomass of above of tobacco.(3)Effects of different nitrogen rates on physiological characteristics of tobacco leaves during the growth of tobacco plantAfter adding nitrogen,the accumulation of reducing sugar and total sugar were increased by 35.3%and 17.2%respectively,and the contents of nicotine and total nitrogen were also promoted.Reduced nitrogen fertilizer reduced the synthesis of nicotine and total nitrogen,compared with conventional fertilization decreased by 27.7%and 32.3%,while reducing sugar and total sugar accumulation decreased by 18.8%and 9.4%respectively.The potassium content of increasing and decreasing N fertilizer was 2.63%and 2.56%respectively,which was not much difference from conventional fertilization,so it had little effect on the potassium content.(4)Effect of different nitrogen rates on the mineral elements of flue cured tobaccoThe content of Fe in tobacco leaves was affected by the reducing nitrogen application or adding nitrogen fertilizer,and the iron content in the middle leaves of tobacco was decreased by 64.6%and 39.2%respectively compared with the conventional fertilization;Reduction of nitrogen fertilizer decreased the content of Mn was 88.6%,significantly affect the Mn content of tobacco leaves;In view of the middle and lower leaves,the content of B was the highest in the conventional treatment,reaching 23.06ug/g and 21.53ug/g respectively;In view of the upper-leaves,the content of B was the highest in the treatment of adding nitrogen fertilizer,7%higher than the conventional fertilization,23.8%higher than the reduction of nitrogen fertilizer,therefore,adding nitrogen fertilizer could promote the content of B in the upper leaves,but it could not promote the B content of the middle and lower leaves.(5)Effect of different nitrogen rates on conventional chemical components of flue cured tobaccoAdding nitrogen fertilizer,reducing sugar and total sugar content of middle leaves were increased by 20.3%and 14.8%,significantly enhanced the content of both sugars.The content of nicotine in the upper leaves of adding nitrogen fertilizer treatment was 2.84%,which was significantly higher than that of conventional fertilization and less application of nitrogen fertilizer,but the chlorine content was only 0.21%,and the content of chlorine in conventional fertilizer was 0.65%,which significantly reduced the content of chlorine in flue-cured tobacco.Comprehensive analysis of two sugar ratio and other indicators,the worst performance of the reduction of nitrogen fertilizer,increasing the application of nitrogen fertilizer and conventional fertilizer have their own advantage.(6)Effects of different nitrogen rates on neutral aroma components of flue cured tobacco(C3F)Increasing nitrogen application,the carotenoids and aromatic components of the cartenoids were compared with conventional fertilization high 2.8%,the accumulation of degradation products of phenylalanine increased by 14.2%,the content of Maillard reaction products decreased by 12.0%,has little effect on the degradation products of cembranoids;Reduction of nitrogen fertilizer,the carotenoids and aromatic components of the cartenoids and phenylalanine degradation products were accumulated than conventional fertilization decreased by 6.2%and 14%,the content of Maillard reaction products had no obvious difference with conventional fertilization,but cembranoids degraded products decreased by 33.2%.(7)Effect of different nitrogen rates on tobacco(C3F)polyphenol compoundsIncreasing nitrogen application,the content of chlorogenic acid was 18%higher than conventional fertilization,but for the synthesis of scopoletin and rutin had no significant effect.Reduction of nitrogen fertilizer can significantly reduce the synthesis of chlorogenic acid and rutin,and the contents of them were reduced by 10.9%and 17.7%respectively,reducing nitrogen has no effect on scopoletin content change.(8)Effect of different nitrogen rates on non volatile organic acids in flue-cured tobacco(C3F)Adding nitrogen fertilizer of nonvolatile organic acids in tobacco leaves were lower 20.60%than conventional nitrogen.Reducing nitrogen fertilizer of succinic acid,malic acid,citric acid content were significantly higher than other treatments(P<0.05).(9)Effect of different nitrogen rates on the sensory quality of flue-cured TobaccoAdding nitrogen fertilizer of the upper leaves of flue-cured tobacco sensory quality score was 78.6,the highest score,mainly in two aspects of the quality and quantity of aroma,aroma quantity was 16.4,the highest score,indicating a sufficient amount of aroma.Reducing nitrogen application of flue-cured tobacco on the three parts of the score was the lowest,the sensory quality of the worst.(10)Effect of different nitrogen rates on economic characters of flue-cured tobaccoIncreasing nitrogen application,the output value reached 41670.53 Yuan/hm~2,the proportion of medium and high tobacco was 72.31%,and the output value was slightly higher than that of conventional fertilizer application.The output value of the reduced nitrogen fertilizer was only 32540.25 Yuan/hm~2,lower than the conventional fertilization,which is 41086.31 Yuan/hm~2,the proportion of middle and upper tobacco was 4.7%lower than that of conventional fertilization.