海螺沟冰川退缩区土壤元素分布特征及影响因素

摘要

In the processes of soil formation and development,the distribution characteristics of soil elements are essential to the healthy development of terrestrial ecosystems.In this study,six sampling sites (0,30,40,52,80 and 120 years) were selected according to the soil age in the Hailuogou glacier retreat area.Eighteen elements in the O horizon (organic horizon),A horizon (material horizon) and C horizon (parent material) were selected to investigate their distribution characteristics,and then the main influencing factors were deciphered.The results showed that the concentrations of all elements in the C horizon of the glacier retreat area did not vary markedly,indicating the homogenous nature of the soil parent materials.In the surface soils (O horizon and A horizon),Al,Ba,Ca,Cr,Cu,Fe,K,Mg,Mn,Na,Ni,Sr,Ti and V were significantly depleted,P and Zn were moderately depleted,whereas Cd and Pb were prominently enriched.With soil development and vegetation succession,especially when coniferous species dominated,the soil weathering,plant uptake and runoff loss may be the main factors contributing to the loss of the depleted elements.The high enrichment of Cd and Pb was mainly attributed to the atmospheric deposition and the returning of plants.%土壤形成和发育过程中,元素的赋存特征对陆地生态系统的健康发育至关重要.本研究选择海螺沟冰川退缩区,按照土壤年龄设置了6个采样点(0,30,40,52,80和120年),调查了18种元素在O层(有机层)、A层(矿物质层)和C层(母质层)的分布特征,并分析了主要影响因素.结果显示,在海螺沟冰川退缩区C层土壤中所有元素的浓度变化不大,反映了母岩基质相对单一;在表层土壤(O层和A层)中,A1、Ba、Ca、Cr、Cu、Fe、K、Mg、Mn、Na、Ni、Sr、Ti、V发生明显亏损,P和Zn次之,而Cd和Pb存在明显富集.随土壤发育和植被演替,大多数元素的亏损程度增加,特别在针叶林阶段明显高于植被演替前期.土壤风化、植物吸收和径流损失对大多数元素的亏损具有重要影响,而Cd和Pb的高度富集主要归因于大气沉降和植物的归还作用.