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在中国西北黄土高原地区,水分是树木生长发育的主要限制因子。根系分布特征由于反映了树木对环境条件的利用程度而具有更加特殊的生态意义。本研究选择阳坡和阴坡不同立地上年龄一致的刺槐林调查了根系分布特征。根系垂直分布特征的调查结果表明,在所有立地上,根系生物量随着深度的增加而降低,其中细根的分布深度大于粗根的分布深度。方差分析结果表明:不同立地上不同径级根系的分布特征也有明显的差别,粗根是差异存在的主要原因,阴坡立地上的根系生物量,特别是细根生物量大于阳坡立地上的。对根系消弱系数的分析结果表明,阴坡立地上的根系消弱系数大于0.982,而阳坡立地上的根系消弱系数小于0.982,说明阴坡立地上刺槐根系的生物量在深层土壤中的分布相对量更大一些。其中细根的根系消弱系数大于粗根的,这种根系分布特征有利于根系对深层土壤水分养分的吸收利用,进而促进树木地上部分的生长发育。图3表3参15。
In the Loess Plateau of Northwest China, water is the main limiting factor for tree growth and development. The distribution of root system has more special ecological significance because it reflects the degree of utilization of trees by environmental conditions. In this study, the distribution characteristics of root system were investigated on the same age locusts on sunny and shady slopes. Root vertical distribution of the survey results showed that at all sites, root biomass decreased with increasing depth, in which the depth of distribution of fine roots is greater than the depth of the distribution of coarse roots. Analysis of variance showed that there were also significant differences in the distribution characteristics of roots with different diameter grades on different sites. The reason for the difference was the presence of coarse roots. The root biomass, especially the fine root biomass, on shady slopes was greater than that on sunny slope . The results of root system attenuation coefficient analysis showed that the root system attenuation coefficient was more than 0.982 on the shady slope and less than 0.982 on the sunny slope, indicating that the root biomass of R. pseudoacacia on the shady slope was in the deep soil The relative amount of distribution is larger. Among them, root exudation coefficient of fine roots was larger than that of coarse roots. The root distribution characteristics were favorable for root system to absorb and utilize soil nutrient in deep soil, and then promote the growth of trees. Figure 3 Table 3 Reference 15.