摘要
[Objectives]This study was conducted to investigate the effects of different potash regimes on the leaf structure and some physiological and biochemical and agronomic traits of flue-cured tobacco.[Methods]JSZX-09-011F1,a new strain of flue-cured tobacco,was selected as the experimental material,and the effects of different quantities and modes of application on the leaf structure and certain physiological and agronomic traits of flue-cured tobacco were investigated.[Results]The K treatment was superior to zero K treatment on all indicators.Decreasing potassium appropriately(360 kg/hm^(2))and postponing potassium application(in a ratio of basal fertilizer to topdressing fertilizer of 3:7)were advantagous.In specific,①it improved the canopy structure and increased penetration of light to lower levels,narrowing the angles between leaf and stem of the middle leaves and of the plant as a whole,with a reduction of 1.76°and 2.58°respectively compared with high basal potassium treatment.Meanwhile,it shortened the internode length,which is conducive to improvement in the structure of the leaf.②Increasing the proportion of potash top dressing made possible a distinct reduction in potash fertilizer input,but this measure did not have any effect on the potassium content in the middle and upper leaves in the later stage of growth(from vigorous growth to maturity),and chlorophyll content in the canopy increased with the increase in the proportion of top dressing.③At appropriate potash application levels,as top dressing proportions rose,nicotine content tended to decrease.④A potassium postponing regime with less basal application and more top-dressing was not only able to save 90 kg of potash per hectare,but also advantageous to nitrogen-potassium balance and late stage potassium effectiveness,ultimately achieving a balance between yield and quality and obtaining higher output value.[Conclusions]This study lays a foundation for the research on suitable application period and quantity of potassium fertilizer.
