Abstract: Soil salinity is critical in affecting the aquatic ecosystem quality of wetland,and its distribution characteristics and transport are closely related to water conditions of wetland. To explore the distribution characteristics of topsoil salt under diverse flooding conditions on the grassland riverine wetland,we set up five sampling regions and three flooding conditions along the horizontal and vertical directions of the Hui River basin respectively,in Hui River wetland of Hulunbuir grassland from July to August,2020,and collected soil samples for principal component analysis. The results showed that:the salinization of Hui River wetland was severe with 62.5% topsoil salinized,the main type of soil salinization was sulfate saline soil;and the degree of soil salinization gradually increases from the source to the catchment. The physicochemical properties,salt distribution and ion composition of topsoil in the Hui River wetland showed different characteristics,which were significantly affected by the diverse flooding conditions and regions of the river (P<0.05). Principal component analysis showed that the main characteristic factors affecting soil salinization in the study area were Na⁺,Cl^-,SO^2-₄,and the degree of soil salinization was mainly affected by salt content,alkalinity characteristics and soil structure.

Key words: Hulunbuir grassland, Hui River wetland, Flooding conditions, Topsoil salt

摘要： 土壤盐分是影响湿地水生态质量的重要要素,其分布特征和迁移规律与湿地水分状况息息相关。为探究草原河流湿地不同淹水状态下表层土壤盐渍化特征,2020年7—8月在呼伦贝尔草原辉河湿地,沿辉河干流河道水平和垂直方向分别设置5个取样区和3种淹水状态,采集土壤样品并进行主成分分析。结果表明:辉河湿地盐渍化严重,62.5%的土壤处于盐化状态,土壤盐化类型以硫酸盐盐土为主,由源头至汇水口土壤盐渍化程度逐渐加大;受淹水状态及河流不同区域的显著影响(P<0.05),辉河湿地表层土壤理化性质、盐分分布及离子组成呈现出不同特征;主成分分析表明,影响研究区土壤盐渍化的主要特征因子为Na⁺,Cl^-,SO^2-₄,土壤盐渍化程度主要受盐分含量、碱化特征和土壤结构的影响。

关键词: 呼伦贝尔草原, 辉河湿地, 淹水状态, 表层土壤盐分