黄土丘陵区不同植被根系数量特征及离散程度

根系的空间分布与植物自身的生物学特性、土壤资源、土壤结构等因素有密切的关系。对黄土丘陵区3种植被类型根系的数量特征及离散程度进行了研究,结果表明:山杨、灌丛和油松林地的根系数量随着根系径级的增加而减少;山杨林地根系最丰富,油松林次之,灌丛地根系数量最少。3种植被根系离散程度随深度的增加有明显的差异,其中灌丛和山杨林根系的离散指数在15cm深处达到最大值,随后又降低,而油松林的变化没有明显规律。无论是表层或是深层,3种植被根系离散指数均小于1,说明植被根系在土壤中呈聚集分布。在土壤相对均质的黄土地区,根系的空间聚集分布可能是根系的固有特性。

Quantitative characteristics and scattering degree of different vegetation root systems in hilly regions of Loess Plateau

The spatial distribution of root system is closely related with the biological properties of plant itself,soil resources,and soil structure,etc.In this paper,the quantitative characteristics and scattering degree of the root systems of three vegetation types in the hilly regions of Loess Plateau were studied.The results showed that the amount of root systems decreased with the increase of their diameter class,and Populas davidiana had the most abundant root system,followed by P.tabulaeformis,and shrub.There existed obvious differences in the scattering degree of root system with soil depth among the three vegetations.The root scattering index of P.davidiana and shrub was up to the maximum at the soil depth of 15 cm,and decreased then,while it had no obvious change for P.tabulaeformis.Whether in surface soil or in deeper soil layers,the root scattering index of the three vegetations was less than 1,suggesting that the root systems of the vegetations were in clustered distribution.In the study regions with relatively homogeneous soils,such a clustered distribution was possibly the intrinsic property of the root systems.