25年生‘富士’苹果园冠层光能分布格局及其季节变化规律

Solar Radiation Distribution Pattern in Canopy Interspaces and Its Seasonal Fluctuation in a 25-year-old'Fuji'Apple Orchard

为研究不同季节富士苹果园内冠层光能分布及冠层透光率随叶面积指数的变化规律,以25年生‘长富2号’苹果为主要试材,采用3415-LQF5光量子计和WinSCANOPY植物冠层分析仪于生长季节连续测定果园冠层内光能空间分布和叶面积指数的变化。结果表明,不同冠层和不同树冠空间方位的光能分布变化以及最大光照强度的获得与太阳高度角的变化密切相关;不同冠层的消光系数为次外层>内层>外层;不同季节各冠层的光能分布呈现单峰曲线,在正午时刻达到日周期最大值,不同季节冠层平均光照强度依次为春季>夏季>秋季;各冠层生长季节平均光照强度依次为外层>次外层>内层>近地面;相对光照强度小于30%的树冠所占比例随生长季节的延长逐渐增加;年周期冠层透光率与叶面积指数呈相反的变化趋势。相关性分析表明,苹果不同方位冠层平均光照强度与叶面积指数呈显著的负相关(r=-0592*),与林隙分数呈极显著的正相关(r=0.722**),与平均叶倾角呈显著的正相关(r=0.647*)。

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 were 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, 0.722, and0.647, resuectivelv