不同打叶模式对烤烟单叶重和产质量的影响

目的]研究田间摘除脚叶和顶叶对烤烟不同叶位单叶重及烟叶产质量的影响,以期为制订田间鲜烟叶处理措施、优化烟叶结构及提升烟叶质量提供参考依据.方法]以云烟97为参试品种,设3种打叶模式处理,处理1(T1,CK):团棵期(移栽后约40 d)打掉底部奶脚叶,现蕾期烟株第一朵中心花开时(移栽后约60 d)打顶,将花枝连同其上多余叶片一同打去,留叶数18片;处理2(T2):在T1基础上,打顶时多打掉最下面的2片叶,留叶数16片;处理3(T3):在T2基础上,打顶后20 d再打掉最上部的2片叶,留叶数14片.对各处理不同叶位叶片挂牌标记,按生产标准采收烘烤,逐片分级、称重,计算单叶重、产量、产值、均价及等级结构等指标.结果]随着烟株留叶数的减少,平均单叶鲜、干重均逐渐增加,表现为T1T2(2734.5 kg/ha)>T3(2583.0 kg/ha);T2的上中等烟比例和产值最高,分别为90.18%和61493.1元/ha,与T1差异不显著(P>0.05),两者均显著高于T3.结论]打顶时多摘除2片脚叶可适度增加单叶重,提高烟叶上中等烟比例、均价,产量损失较轻,产值较高;但打顶后20 d再多摘除2片顶叶会导致中、上部叶位单叶重偏重,质量等级下降,对产量、产值造成较大损失.田间进行打叶操作时,建议采用打顶时多打掉2片脚叶的方法,根据烟株长势和营养状况谨慎选择是否在后期再打除2片顶叶.

Effects of different threshing patterns on weight per leaf,yield and quality of flue-cured tobacco

Objective] Effects of removing bottom and upper leaves on weight per leaf of leaves at different positions and tobacco quality were studied to offer a basis for formulating fresh tobacco leaf treatment measures in field,optimizing tobacco structure and improving tobacco quality.Method] A field experiment was carried out using tobacco variety Yunyah97.There were three treatments.Treatment 1 (T1,CK):removed the orignal leaves at the bottom of stick at resettling stage(about 40 d after transplant),and removed the flower branches and extra leaves on it at squaring stage when the first center flower bloomed (about 60 d after transplant),maintaining 18 leaves per plant.Treatment 2 (T2):on the basis of T1,removed two more leaves at the bottom of the tobacco plant at topping stage and maintained 16 leaves per plant.Treatment 3 (T3):on the basis of T2,removed two more leaves at the top of the tobacco plant 20 d after topping,and maintained 14 leaves per plant.The leaves at different positions of tested plants were labeled.According to production standards,the leaves of the tested plants were harvested and cured,and every leaves were graded and weighted one by one,then weight per leaf,yield,output value,average price,grade structure and other indicators were calculated.Result] As the number of leaves remained decreased,both the average fresh weight per leaf and average dry weight per leaf increased and presented T 1 ＜T2＜T3.The differences in average fresh weight per leaf and average dry weight per leaf among different threshing patterns were significant(P＜0.05,the same below).The difference in weight per leaf among different treatments mainly existed in middle leaves(leaf position No.7-12) and upper leaves(leaf position No.13-18),no significant difference in lower leaves (leaf position No.3-6) was detected.The yield rank in different threshing patterns was T1 (2818.9 kg/ha)＞T2(2734.5 kg/ha)＞T3 (2583.0 kg/ha).In T2,first-and-second-class rate(90.18％) and production value(61493.1 yuan/ha) were the highest,but it was not significantly different from those of T1 (P＞0.05).But the values of T1 and T2 were significantly higher than those of T3.Conclusion] Removing two more bottom leaves at topping stage can moderately increase weight per leaf,improve first-and second-class rate and average price,and the yield loss of tobacco leaves is smallwith high output value.But removing extra two leaves at top part 20 d after topping causes weight per leaf of middle and upper leaves to exceed standard,quality grade to decline,yield and output value to lose greatly,It is suggested that removing two extra bottom leaves to be removed at topping stage in field.But whether removing two more top leaves later or not should be judged according to the growth and nutrition status of tobacco plants.