Dynamic change of canopy characteristic parameter of flue-cured tobacco with different planting density in high mountainous area of northern Guizhou

Canopy characteristic parameters with different planting density at different growth stages were investigated systematically in order to explore dynamic change of canopies characteristic of flue-cured tobacco in high mountainous area of sub plateau of northern Guizhou. The results showed that under the condition of a constant line spacing (110 cm), the leaf area accumulation per plant of plant space 50-75 cm was not obvious different, but they were higher 0.58~0.66 m2 than that of plant space under 38-43 cm. The leaf area accumulation of population of plant space 50 cm was the highest than that of the others, that was higher 0.96 m2/m2, 0.42 m2/m2, 0.70 m2/m2, 0.42 m2/m2 than that of plant space 75 cm, 60 cm, 43 cm, 38 cm. The rate of leaf area accumulation per plant or population beyond or under 50 cm was decreased. The planting density was negatively correlated with the light transmittance of the ridge and middle leaves, and that was positively correlated with leaf orientation value of upper and middle leaves and the vertical ratio of leaf. The light transmittance of planting space under 50 cm was lower than that of the others but their vertical ration of leaf and leaf orientation value of middle and upper leaf were increase. The conclusion was that the planting density with plant spacing 50 cm was not only favorable for the coordinated development of leaf area per plant and population, but also guaranteed the light transmittance of the ridge and middle leaves in high mountainous area of sub plateau of northern Guizhou.