不同肥料运筹模式下采收时间对烤烟经济性状及品质的影响

为探讨不同肥料运筹模式下适宜的烟叶采收时间，以NC55为材料，设置了3种肥料运筹模式，分别为：氮磷钾肥全部作基肥施用（T1）；磷肥全部基施，氮肥和钾肥基追比例为7：3（T2）；磷肥全部基施，氮肥和钾肥基追比例为5：5（T3）；3个采收时间，分别为打顶后30 d（S1）、打顶后35 d（S2）、打顶后40 d（S3），分析了不同处理对叶片SPAD值及烤后烟经济性状、化学成分和质量的影响。结果表明，相同肥料运筹模式下，随采收时间推迟，叶片SPAD值减小；烤后上等烟比例、上中等烟比例、均价和单叶重先增加后降低，均以打顶后35 d采收最高；但T3模式下的上中等烟比例、均价和单叶重打顶后35 d与40 d采收差异较小。随采收时间推迟，烟叶烟碱含量显著降低，还原糖含量显著提高，糖碱比和两糖比显著增加；烟叶总糖含量先增加后降低，打顶后35 d采收最高。不同肥料运筹模式下，氮钾追肥比例越高，SPAD值随采收时间下降幅度越小；氮钾肥基追比例为10：0、7：3和5：5的处理，分别在打顶后30、35和40 d采收感官质量总得分最高。可见，磷肥全部基施条件下增加氮钾肥追施比例推迟了烤烟的成熟落黄和获得最佳感官质量的采收时间。

Effects of Harvesting Time on Economic Characters and Quality of Fluecured Tobacco Under Different Fertilization Application Regimes

In order to study the suitable harvest time of tobacco leaf under different fertilization application regimes,NC55 culivar was used and three fertilization application regimes were set up as follows:all nitrogenous,phosphorous and potassic fertilizers were used as basal fertilizer(T1);phosphorous fertilizer for basal application in total,nitrogenous fertilizer and potassic fertilizer were applied with a base and topdressing ratio of 7:3(T2);phosphorous fertilizer for basal application in total,nitrogenous fertilizer and potassic fertilizer were applied with a base and topdressing ratio of 5:5(T3).The three harvest time treatments were as follows:30 days after topping(S1),35 days after topping(S2)and 40 days after topping(S3).The leaf SPAD value,economic characters,chemical composition,and quality of tobacco after curing were analyzed.The results indicated that for the same regime of fertilization application,the leaf SPAD value decreased with the extension of harvest time after topping.The proportion of high-quality tobacco,high and middlequality tobacco after curing,the average price and the single leaf weight all increased firstly and then decreased and all of them had the highest value at 35 days after topping.There was smaller differencesof the proportion of high and middle-quality tobacco,the average price and single leaf weight for the T3 regime between treatment of 35 and 40 days after topping.With the extension of harvest time,leaf nicotine content significantly decreased,reducing sugar content,reducing sugar/nicotine,and reducing sugar/total sugar significantly increased,the total sugar content firstly increased and then decreased,and showed the highest at 35 days after topping.At different fertilization application regimes,the reduction of leaf SPAD value decreased following higher ratio of nitrogenous and potassic fertilizers topdressing.When the base and topdressing ratio of nitrogenous and potassic fertilizers were 10:0,7:3 and 5:5 respectively,the harvest time for the highest sensory quality of flue-cured tobacco were 30 days,35 days and 40 days after topping,respectively.It can be concluded that the increasing the top dressing ratio of nitrogenous and potassic fertilizers with total basal application of phosphorous fertilizer delayed the harvest time to get the best quality.