| In order to reduce the amount of ferilizer application,optimize the agricultural practices,and improve the the yield and quality of flue-cured tobacco,the flue-cured tobacco variety K326 was selected to study the effects of the planting density,nitrogen application and remained leaf number on the yeild and quality of flue-cured tobacco by a field split block experiment located in Hechi city,Guangxi province.The results were as followed:1.the comprehensive control measures have an extremely significant effects on height of tobacco plant in Luocheng and Nandan of Hechi.The highest plant height of flue-cured tobacco grown in Luocheng city was found in treatment with density of 1200 plants/667m2,nitrogen application in 6.0kg/667m2,and remained 19 leaves.The highest plant height of flue-cured tobacco grown in Nandan city was observed in in treatment with density of 1200 plants/667m2,nitrogen application in 7.5kg/667m2,and remained 21 leaves.While the lowest plant height of flue-cured tobacco in Luocheng city was observed in treatment with 6(1200 plants/667m2(planting density),7.5 kg/667m2(nitrogen),15(Luocheng)/17(Nandan)(number of remained leaves)),which was the same as in Nandan.The control measures of different levels have no significant effect on the height of the tobacco plant in Luocheng,while the nitrogen application has the significant effect on the height of the tobacco plants in Nandan,The tobacco plant growth was significantly imporved with the increase of nitrogen rates.2.the comprehensive control measures have the significant effects on the yield and proportion of high grade leaves in Luocheng and Nandan.Under treatment 5,the yield,output value,and the economic character of flue-cured tobacco grown in Luocheng were highest than other treatments.3.Treament 9(1400 plants/667m2(planting density),7.5 kg/667m2(nitrogen),17(Luocheng)/19(Nandan)(number of remained leaves))and Treament 3(1000 plants/667m2(planting density),7.5kg/667m2(nitrogen),19(Luocheng)/21(Nandan)(number of remained leaves));The yield of Treatment 3 was the highest,the yeild and proportion of high grade leaves were higher,and the economic character is the best in Nandan,then Treament 2(1000 plants/667m2(planting density),6.0 kg/667m2(nitrogen),17(Luocheng)/19(Nandan)(number of remained leaves))and treament 9.The control measures of different levels had no significant influence on the yield and proportion of high grade leaves of the flue-cured tobacco in Luocheng.While the different levels of Planting density had the significant effects on the the yeild,proportion of high grade leaves and output value of the flue-cured tobacco in Nandan,and the different application levels of nitrogen had the significant effects on the output value.Moreover,the different number of remained leaves also had the significant effects on yield and output value of flue-cured tobacco.3.The C3F and B2F of tobacco leaves grown in Hechi contained relatively lower nicotine content in treatment 7(1400 plants/667m2(planting density),4.5 kg/667m2(nitrogen),19(Luocheng)/21(Nandan)(number of remained leaves)),Treament 1(1000 plants/667m2(planting density),4.5 kg/667m2(nitrogen),15(Luocheng)/17(Nandan)(number of remained leaves)),Treament 5 and Treament 4(1200 plants/667m2(planting density),4.5 kg/667m2(nitrogen),17(Luocheng)/19(Nandan)(number of remained leaves)),and which also contained relatively higher the ratios of reducing sugar to nicotine,and suitable proportion of the overall chemical composition.Generally,chemical composition of C3F tobacco leaves in Nandan were more suitable for the coordination,and the nicotine content of B3F tobacco leaves of all treatments was relatively higher,in comparison,the reducing sugar content and the ratios of reducing sugar to nicotine of Treatment 4,Treament 7,Treament 8(1400 plants/667m2(planting density),6.0 kg/667m2(nitrogen),15(Luocheng)/17(Nandan)(number of remained leaves)),Treament 2 was slightly higher,chemical composition was more suitable and harmonious.Treatment at levels A2(1200 plants/667m2)、B1(4.5 kg/667m2)、B2(6.0 kg/667m2)and Levels of A3、B1、B2、C3 were better method to reduce the content of nicotine and improve the coordination of the chemical composition of tobacco leaves in Luocheng.4.the thickness of the tobacco leaf of Treatment 7,Treament 4,Treament 8 and Treament 6 were slightly thinner than other treatments,also the leaf weight was slightly lighter,the balance water content and free burning time were higher,relatively better;Compared to the other treatments,thinner leaves,higher moisture content,and longer free burning time of tobacco was observed in Treament 3,Treament 8,Treament 7 and Treament 2.5.The aroma components of tobacco leaves of C3F were studied in this paper,the results show.The quality of Treatment 3,Treament 9,Treament 8 and Treament 1 in Luocheng and Treatment 1,Treament 8,Treament 7 and Treament 9 in Nandan was relatively better than that of other treatments,and the quality characteristics of the aroma index A and the ratio of solandone to damadone were lower.The regulation of different levels of Luocheng and Nandan had no obviously law on aroma composition and aroma index,comprehensive aroma quality of A3,C3 levels of Luocheng and Nandan was better,while the tobacco aroma transmission of A1(1000 plants/667m2)level was better than that of A3(1400 plants/667m2)in Luocheng.6.The fragrance scores of tobacco in Luocheng were ranged from 7.0 to 7.8 among different treatments;The fragrance scores of tobacco in Nandan were ranged 6.2 to 6.5 among different treatments.Generally,the aroma of tobacco leaves Treatment 4,Treament 8,Treament 7,Treament 6 in Luocheng and Treatment 7,Treament 5,Treament 4,Treament 9 were better,the aroma were more sufficient,the mixture were lighter,the overall score were higher,the quality of the evaluation were better.7.The treatment 5,Treament 9 in Luocheng and Treatment 3,Treament 9 in Nandan were recommeded as optimal agricultural practices to obtain higher yield and quality of flue-cured Tobacco... |
