| 摘要: |
| 【目的】探讨苹果树群体在生长过程中冠层结构的变化特征及其影响。【方法】以山西省吉县东城乡3～20年生富士苹果树为试材，每种树龄群体选择12株样树，使用LAI-2000冠层分析仪，对其叶面积指数（LAI）、冠层开度（DIFN）、平均叶倾角（MTA）、消光系数（K）等冠层参数进行测算，同时测定干周粗、树高、冠幅、枝下高、冠高和郁闭度等果树形态指标，然后对不同树龄富士苹果树群体的冠层参数及其形态指标进行对比分析。【结果】随着树龄的增加，苹果树群体的DIFN不断减小，从0.89下降到0.09；LAI逐渐增加，从0.29增加到3.54；MTA的变化总体呈下降趋势，但是8和12年生的苹果树群体MTA又呈上升趋势，MTA与树冠的5个天顶角关系密切，当两者角度接近时，该天顶角方向上的太阳光线入射较多；K逐渐增加，从0.38增加到0.68。【结论】综合冠层结构参数来看，3～10年生苹果树群体内透光、通风状况良好，其中3～8年生苹果树群体DIFN在0.4以上，LAI小于1.5，MTA在30°以上，K小于0.4；10年生苹果树群体整体长势好，DIFN为0.28，LAI为2.17，MTA为26°，K为0.59，这种冠层结构有利于群体发展；12年以上苹果树群体DIFN在0.2以下，K增加到0.6以上，群体内部光照少，通风差；而20年生苹果树群体DIFN不足0.1，LAI高于3.5，MTA为8°，K接近0.7，此时群体长势差，果树群体外围郁闭，内部光秃。同时，当冠层天顶角与MTA角度相近时，该天顶角方向的冠层开度较大，可根据不同树龄MTA的特征，并结合当地太阳高度角的变化特征，来进行果树修剪,控制树冠张开的角度。 |
| 关键词: 苹果树树龄 LAI-2000冠层分析仪 冠层结构 叶面积指数 |
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| 基金项目:国家“十一五”科技攻关项目(2006BAD03A05) |
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| Study on the canopy characteristics of different ages Fuji apples trees in Jinxi Loess Plateau area |
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| Abstract: |
| 【Objective】The study was to explore the canopy changing characteristics of the Fuji apples in its life activity and its impact.【Method】At Dongcheng township of Jixian county in Shanxi province,3 to 20 years old Fuji apple trees were used as experimental material,12 trees from the different age communities,were chosen to determine the canopy structure parameters of different age apple trees,such as LAI,DIFN,MTA and extinction coefficient (K) using the LAI-2000 canopy analysis instrument.At the same time,the shape index of different age apple trees,such as the trunk girth,height,crown,height below canopy,and so on was obtained,then the anopy structure parameters and the the shape index of different age Fuji apple trees were compared and analyzed.【Result】With the increases of age,the DIFN is reduced from 0.89 to 0.09.The LAI is gradually increased from 0.29 to 3.54.The change of MTA is not very clear with a downward trend in the overall phase,but with a rise in the 8 and 12,close to five zenith angle.When they are similar in the angle,the direction of the zenith has more sunlight injection.【Conclusion】Looking at the overall canopy structure parameters,the canopy structures of 3 to 10 years old apple trees are better than others.DIFN of 3 to 8 years old apple trees is above 0.4,LAI less than 1.5,MTA above 30 degree,and the extinction coefficient less than 0.4.These communities have better translucent and ventilation;the 10-year-old apple community grow well as a whole.DIFN is 0.28,LAI 2.17,MTA 26 degree,and the extinction coefficient 0.59.This canopy structure is conducive to group development;DIFN of apple community over than 12 years old is lower than 0.2,the extinction coefficient is increased over 0.6.The communities are few with light and wind;DIFN of 20-year-old community is less than 0.1,LAI higher than 3.5,MTA 8 degree,and the extinction coefficient up to 0.7.In this moment,the community light environment is the worst.The community appears external canopy,internal bare.When the zenith angle is close to the MTA,the zenith angle direction has large DIFN,so it can provide scientific basis to the fruit tree pruning,and promote the photosynthetic productivity of the apple trees community. |
| Key words: age of apple tree LAI-2000 canopy analyzer canopy characteristic leaf area index |
