阅海城市湿地典型植被群落土壤活性有机碳组分分布特征

Distribution Characteristics of Soil Labile Organic Carbon Fractions in Typical Vegetations Communities of the Yuehai Urban Wetland

明确湿地土壤活性有机碳组分分布特征对评价旱区生态效益、实现“双碳”目标等有重要作用。本研究以银川市阅海城市湿地为研究对象,分析城市湿地典型植被群落不同土层土壤有机碳、全氮及活性有机碳的分布特征。结果表明:0~60 cm土层芦苇(Phragmites australis)、茭白(Zizania latifolia)、香蒲(Typha orientalis)、菖蒲(Acorus tatarinowii)及碱蓬(Suaeda salsa)生长区土壤有机碳平均含量分别为2.13,2.99,2.77,3.35和3.15 g·kg^(-1)。各植被类型下活性有机碳组分中可溶性有机碳变化规律与总有机碳一致。易氧化碳与微生物量碳含量均表现为碱蓬高于其他植被类型。湿地土壤有机碳含量与黏粒呈显著负相关,与全氮呈显著正相关。冗余分析发现植被类型和土层深度差异是影响土壤有机碳及其组分分布的主要因子。该研究表明植被类型会影响湿地的固碳能力,香蒲较其他植被固碳能力更强,而碱蓬生长区碳库稳定性及固碳能力均较弱。

It is important to characterize the distribution of labile organic carbon components in wetland soils to evaluate the ecological benefits of drylands and achieve the“double carbon”target.This study was conducted to investigate the distribution characteristics of organic carbon,total nitrogen,and labile organic carbon in different soil layers of typical vegetation communities around the urban wetlands in Yinchuan City,using the Yuehai Urban Wetland as the research object.The results showed that the average contents of organic carbon in the 0~60 cm soil layer were 2.13,2.99,2.77,3.35,and 3.15 g·kg^(-1) for Suaeda salsa,Zizania latifolia,Phragmites australis,Typha orientalis and Acorus tatarinowii.The change of dissolved organic carbon in the labile organic carbon fraction was consistent with the total organic carbon under each vegetation type,but easily oxidated organic carbon and microbial biomass carbon were both higher in Suaeda salsa than in other vegetation types.The organic carbon content of wetland soils was significantly negatively correlated with clay grains and positively correlated with total nitrogen.Redundancy analysis revealed that vegetation type and soil depth differences were the main environmental factors affecting the distribution of soil organic carbon and its fractions.This study showed that vegetation types affected the carbon sequestration capacity of wetlands,and Typha orientalis had stronger carbon sequestration capacity than other vegetation types,while the carbon pool stability and carbon sequestration capacity of Suaeda salsa planting area were weaker.