不同演替阶段群落根系分布与土壤团聚体特征的协同变化

Coordinated Variation Between Root Distributions and Soil Aggregate Characteristics at Different Successional Stages

采用空间代替时间的方法,选取黄土高原丘陵区退耕地演替前期(茵陈蒿)、中期(铁杆蒿)和后期(白羊草)典型群落,研究了不同植物群落在不同演替阶段的根系特征、分布格局及其与土壤团聚体之间的关系。结果表明:群落根系主要为<2mm的细根,且多向土壤表层集中,根长密度、表面积,根系生物量以及比根长表现出随着直径的增大而减小规律。同时随着演替的进行,土壤团聚体稳定性有所增强,根长密度和根表面积也表现出增长趋势。对比群落根系分布与土壤团聚体的相关关系可知,表层0.5~2mm的细根根长、表面积与根系生物量和土壤团聚体稳定性极显著相关,说明了植物细根在群落演替以及土壤结构变化中具有重要作用。

In order to understand the change of root distribution and the relationship with soil aggregate structure in different plant communities of succession stage,the characteristics of roots and soil aggregates of Artemisia capillaries,Artemisia gmelinii,Bothriochloa ischaemun community,which are typical species at abandoned stage in loess hilly region were studied by using the method of substituting spatial difference for time change.The results show that in the herbaceous community fine roots are the main part of whole roots and most of roots distribute in the upper soil layer;the root length density(RLD),root surface area(RSA),root biomass and specific root length(SRL)decreased with the increase of the size diameters(<0.5,0.5~1.0,1.0~1.5,1.5~2,>2.0 mm).The stability of soil aggregates,RLD and RSA increased with succession durations.The stability of soil aggregates is significantly correlated with fine RLD,fine RSA and fine root biomass in the upper soil layer,which indicates that fine roots play an important role in vegetation succession and soil structure.