盐碱芦苇湿地土壤活性有机碳组分垂直分布及相关性分析

Vertical Distribution and Correlation Analysis of Soil Active Organic Carbon Components in Saline-alkali Reed Wetland

湿地是地球生态环境的重要组成部分,也是碳循环和转化的重要场所,湿地土壤活性碳库与气候变化有着密切联系。盐碱湿地具有独特的土壤性质,以吉林西部松嫩平原盐碱湿地为例,以土壤类型图和土地利用类型图为基础,选取吉林松原查干湖天然盐碱芦苇湿地为研究对象。明晰盐碱湿地土壤活性有机碳组分垂直分布及影响因素分析,为盐碱区脆弱湿地生态环境管理与保护、区域碳库源汇研究及客观评价其在区域气候变化中的作用,以及退化湿地生态恢复提供科学依据。在研究区丰水期进行采样,在地上植被为芦苇的湿地土壤地块设置9个采样区,每个区域设置4个采样点,按照0~10、10~20、20~30、30~40、40~50 cm分层采集土壤样品。分析测定土壤有机碳(soil organic carbon,SOC)、易氧化有机碳(readily oxidized organic carbon,ROOC)、水溶性有机碳(water soluble organic carbon,WSOC)、微生物量碳(microbial biomass carbon,MBC)含量及土壤pH、含水率、容重、孔隙度等,以阐明盐碱芦苇湿地土壤有机碳及其活性组分分布特征及影响因素。结果表明:查干湖盐碱湿地土壤有机碳及活性组分垂直分布规律明显,呈现伴随土层加深而逐渐减少的趋势,且在土壤的各个剖面层土壤有机碳含量与易氧化有机碳、水溶性有机碳、微生物量碳含量间呈显著相关;研究中各土壤活性有机碳占土壤有机碳比例不一,呈现ROOC明显高于WSOC和MBC,[w(ROOC)/w(SOC)]%为87.01±10.63 g/kg、[w(WSOC)/w(SOC)]%为0.58±0.06 g/kg、[w(MBC)/w(SOC)]%为8.19±0.72 g/kg;查干湖盐碱湿地土壤有机碳及活性组分垂直分布受土壤pH、容重、孔隙度影响明显,呈显著相关,土壤含水量相对影响较小。

Wetland is an important part of the earth s ecological environment and an important place for carbon cycle and transformation.The active carbon pool of wetland soil is closely related to climate change.The saline-alkali wetland has unique soil properties.In this study,the saline-alkali wetland in the Songnen Plain of western Jilin Province was taken as an example.Based on the soil type map and the land use type map,the natural saline-alkali reed wetland of Jilin Songyuan Chagan Lake was selected as the research object.The aim of this study is to clarify the vertical distribution and influencing factors of soil active organic carbon components in saline-alkali wetlands,to study the ecological environment management and protection of fragile wetlands in saline-alkali areas,to study the source and sink of regional carbon pools,to objectively evaluate their role in regional climate change and degraded wetlands,and to provide a scientific basis for ecological restoration.In the study area,four sampling areas were set up during the flood season.Nine sampling points were set up in each area according to S-type.Soil samples were collected in five layers(0~10,10~20,20~30,30~40,40~50 cm)by snake sampling method in each plot.The contents of soil organic carbon(SOC),oxidizable organic carbon(ROOC),water-soluble organic carbon(WSOC),microbial biomass carbon(MBC)and soil pH,water content,bulk density and porosity were determined to clarify the distribution characteristics and influencing factors of soil organic carbon and its active components in saline-alkali reed wetland.Results show that the vertical distribution of soil organic carbon and active components in the saline-alkali wetland of Chagan Lake is obvious,showing a decreasing trend with the deepening of soil layer.The content of soil organic carbon is significantly correlated with the content of oxidizable organic carbon,water-soluble organic carbon and microbial biomass carbon;The proportion of soil active organic carbon to soil organic carbon varies in the study,showing that ROOC is significantly higher than WSOC and MBC,[w(ROOC)/w(SOC)]%is 87.01±10.63 g/kg,[w(WSOC)/w(SOC)]%is 0.58±0.06 g/kg,[w(MBC)/w(SOC)]%is 8.19±0.72 g/kg;Vertical distribution of soil organic carbon and active components in the saline-alkali wetland of Chagan Lake is significantly affected by soil pH,bulk density and porosity,showing a significant correlation,while soil water content has a relatively small impact.