Abstract:

With 25 years old Fuji apple trees as the experimental material, to understand the apple orchard canopy light distribution and leaf index change, 3415-LQF5 light quantum meter and WinSCANOPY plant canopy analyzer was used in different seasons to study the light distribution of canopy and light transmittance rate changed with the leaf area index variation. Result showed that the light intensity and the biggest acquisition of different spatial orientation levels were closely related to sun altitude angle. Canopy extinction coefficient showed: sub outer>inter>outer. Daily light distribution curve in canopy in growing seasons showed a single peak at the noon. The average seasonal light intensity showed spring >summer >autumn, and outer canopy >sub outer canopy>inner canopy>near the ground in all the growing seasons. The proportion of the crown volume of the relative light intensity within the canopy account for less than 30% gradually increased in the growing seasons. Annual canopy light transmission rate showed the opposite changing trend with leaf area index. Correlation analysis showed that there was a significant correlation between leaf area index and the average light intensity, gap scores, and average leaf angle, with a correlation coefficient of -0.592*, r=0.722**, and 0.647*, respectively.