不同郁闭程度对苹果园群体结构、冠层微气候的影响

Effects of Different Canopy Densities on Group Structure and Canopy Microclimate of Apple Orchard

以不同郁闭程度‘红富士’苹果园为研究对象,研究隔行去行、轻度郁闭、中度郁闭及重度郁闭对果树冠层微气候、群体结构的影响。结果表明,隔行去行降低了果园树冠覆盖率,果园透光率及冠内透光率均随郁闭程度的增大而减小;郁闭程度影响果园群体结构、枝量及枝类组成,其中单位面积枝量依次为重度郁闭>中度郁闭>轻度郁闭>隔行去行;隔行去行处理的果树短枝比例最高,随郁闭程度的增加叶丛枝比例降低,而长枝与发育枝的比例增高;郁闭程度影响冠层的光照强度,相对光照强度依次表现为隔行去行>轻度郁闭>中度郁闭>重度郁闭,并且4种类型果园的相对光照强度分布均呈现出自上而下、由外到内依次减小的规律;同时,郁闭程度影响冠层的温湿度,树冠温度与相对湿度的分布和变化趋势相反,树冠不同层次温度从上到下逐渐降低,同一层次内温度从外围到内膛逐步降低,树冠不同层次相对湿度则从上到下逐渐增大,同一层次内相对湿度从外围到内膛逐步升高,并且相对湿度的变化幅度较小。

The ＇Red Fuji＇ apple orchards with different canopy densities were used to study the influences of interlaced lines and light, moderate and heavy canopy densities on group structure and canopy microclimate. The results showed that the interlaced lines reduced the tree coverage in apple orchards, and the light transmittance rate of orchard and canopy decreased with the increase of canopy density. Canopy density affected the group structure of orchard, branch number and constitute of branch types. The branch number per unit area was sorted as heavy canopy 〉 moderate canopy 〉 light canopy 〉 interlaced lines. The highest proportion of short shoots could be obtained under the treatment of interlaced lines. With the increase of canopy density, the proportion of foliage branches decreased, while that of long and developing branches increased. Canopy density affected the relative light intensity in canopy, which performed as interlaced lines 〉 light canopy 〉 moderate canopy 〉 heavy canopy. The distribution of relative light intensity in the 4 types of orchards showed decrease rule from top to bottom and from outer to inner loop. Meanwhile, canopy temperature and relative humidity were also affected by canopy density. The distribution and variation of temperature and relative humidity in canopy showed opposite trend. The temperature in different tiers of canopy decreased gradually from upper to lower, and from outer to inner in the same tier. The variation of relative humidity was smaller than that of temperature.