【摘要】 为揭示宁夏南部黄土丘陵区典型草本群落根系垂直分布特征及与土壤团聚体的关系,初步评估乡土草本植物根系对团聚体发育的作用,选取5种典型草本群落（胡枝子、百里香、星毛委陵菜、猪毛蒿、长芒草）,研究了草本根系垂直分布特征、土壤团聚体组成和稳定性以及根系与土壤团聚体之间的关系。结果表明:5种草本根系生物量、根长密度和表面积密度为0.44～2.11 g/m³,0.31～3.51 cm/m³,0.04～1.10 cm²/m³,随土层加深逐渐减小,呈表层聚集型分布。土壤团聚体粒径组成特征为>5 mm团聚体最多（54.44%～67.80%,除猪毛蒿）,较裸地提高17.5%～50.4%,<0.25 mm团聚体第二,其他粒径团聚体很少（<5%）。0—30 cm土壤团聚体R_0.25,MWD,GMD值为52.03%～84.64%,9.57～21.01 mm,1.94～15.17 mm,草本群落间团聚体稳定性差异显著,百里香、星毛委陵菜群落团聚体稳定性最好,各草本群落土壤团聚体R_0.25,MWD,GWD随土层加深先升后降。分析草本根系与土壤团聚体的关系,发现根参数和土壤团聚体稳定性指标未表现出显著相关性,说明几种草本根系在土壤结构变化中的作用尚不明确,试验有待细化。更多还原

【Abstract】 In order to reveal the vertical distribution characteristics of roots and their relationship with soil aggregates in typical herb communities in the loess hilly region of southern Ningxia, and to evaluate the effects of native herb roots on the development of aggregates preliminarily, five typical herb communities（Lespedeza bicolor, Thymus mongolicus, Potentilla acaulis, Artemisia scoparia, Stipa bungeana） were selected to study the vertical distribution characteristics of herb roots, the composition and stability of soil aggregate, and the relationship between roots and soil aggregate. The results showed that the root biomass, root length densities and surface area densities of five types of herbs were 0.44～2.11 g/m³, 0.31～3.51 cm/m³, 0.04～1.10 cm²/m³, respectively, these three indicators gradually decreased with the depth of soil layer, and they mainly distributed in the surface layer. The contents of >5 mm soil aggregates were the greatest, ranged from 4.44% to 67.80%, and increased by 17.5%～50.4% in the communities except Artemisia scoparia compared with the bare land, followed by <0.25 mm aggregates, the contents of the other aggregates were the lest（<5%）. The R_0.25 contents, MWD and GMD values of soil aggregate in 0—30 cm soil layer were 52.03%～84.64%, 9.57～21.01 mm, 1.94～15.17 mm, respectively. There were significant differences in the stabilities of aggregates in different herb communities, the stabilities of aggregate in Thymus mongolicus, Potentilla acaulis communites were the highest. R_0.25, MWD and GWD of soil aggregate of each herb community showed the pattern of rising at first and then decreasing with the depth of the soil layer. The relationship between root distributions and soil aggregates in herb communities was analyzed, it was found that root parameters and soil aggregate stability indicators did not show significant correlation, indicating that the roles of several typical herb roots in soil structure changes were not clear, the trial is to be refined gradually.更多还原