树体结构对板栗冠层光照分布和果实产量及品质的影响

Effect of tree structure on light distribution and yield and quality of Castanea mollissima Bl.

以12年生河北迁西县板栗主栽品种‘燕山早丰’为试材,选择自然开心树形且主枝数和开张角度不同的样株,采用照度计测定树冠不同层次、不同方位的光照强度,研究不同主枝数及开张角度下板栗冠层光照的分布特征,分析树体结构对板栗果实产量品质的影响。结果表明,主枝数和开张角度对板栗内膛光照强度、果实产量、品质有一定影响。当主枝数一定时,随开张角度增大,冠层内膛的光照强度逐渐增加。三主枝、主枝开张角度大于60°的树体其相对光照强度小于30%的树冠体积占树冠总体积的比例最小,为42.857%。当开张角度一定时,主枝数的增加对果实产量及品质影响不显著。三主枝、主枝开张角度大于60°的树体产量最高,为0.225 kg/m2。综合分析可知,自然开心形板栗‘燕山早丰’理想的树体结构是三主枝且开张角度大于60°。

Twelve years old Castanea mollissima cv. ‘yanshanzaofeng’ , a main cultivating variety in Qianxi county of Hebei province, was chosen as test materials. Sample trees with natural open center shape and different main branch number as well as opening angle were selected in the study. The chestnut canopy light distribution character was analysed by measurements of canopy light intensity in different canopy layer and direction under different shoot number and open-ing angle, and the effect of tree structure on yield and quality was also investigated. The results showed that there was certain influence of different main branch and opening angle on light intensity, yield and quality. When main branch number remained the same,the light intensity increased gradually with the opening angle increasing. The crown volume with the relative light intensity less than 30% was the smallest when three main branches were kept and their opening an-gle were more than 60°.The proportion of the crown volume with the relative light intensity less than 30% total crown vol-ume was 42.857%. When the opening angle kept unchanged,there was no significant change in yield and quality with the increasing of main branch number. The highest yield per unit area was 0.225 kg/m2 when the opening angle of three main branches was over than 60°.Comprehensive analysis showed that three main branches with opening angle more than 60° was the best structure for chestnut with natural open center shape.