不同退化高寒沼泽湿地土壤碳氮和贮量分布特征

Distribution and Storage of Soil Organic Carbon and Nitrogen in Alpine Wetland under Different Degradation Succession

为研究高寒沼泽湿地土壤碳氮贮量分布特征,探讨退化高寒沼泽湿地的恢复对策,本试验选择三江源区玛沁县大武滩不同退化高寒沼泽湿地为研究对象,分层采集湿地冻融丘和丘间土壤样品,分析土壤有机碳、总氮含量和贮量变化。结果表明:研究区0~30 cm是高寒湿地有机碳和总氮主要分布区,有机碳和总氮呈正相关关系。冻融丘和丘间的土壤含水量与土壤有机碳、总氮均呈极显著相关关系(P<0.01)。冻融丘和丘间的土壤含水量、有机碳、总氮、碳氮贮量均随着退化程度的加剧呈下降趋势,且冻融丘的下降速度较丘间快。有机碳、总氮、有机碳贮量和氮贮量与冻融丘的数量呈极显著负相关关系,与冻融丘的大小呈极显著正相关关系(P<0.01)。这些结果表明:高寒沼泽湿地土壤含水量、冻融丘的数量和大小对高寒湿地退化中土壤碳氮及贮量具有指示性,建议在高寒湿地修复中加强水分补充和冻融丘的保护。

The distribution characteristics of soil carbon and nitrogen storage in alpine marsh wetland were analyzed so as to explore the restoration strategies of degraded alpine marsh wetland.The samples of frozen-thawing patch and those between the grass patches in different degraded alpine marsh wetlands were taken in Maqin Dawutan in the Sanjiangyuan region.The soil organic carbon and nitrogen contents,and carbon and nitrogen storages in the samples were determined.Results in this study showed that topsoil within 0~30 cm was the main distribution layer of soil organic carbon and nitrogen in alpine wetland.There was a significant positive correlation between soil organic carbon and nitrogen contents.Soil water content at two kinds of patches was significantly correlated with soil organic carbon and total nitrogen(P<0.01).With the increase of the degree of degradation in alpine wetland,the water content,soil organic carbon and nitrogen contents,and carbon and nitrogen storages decreased.The descending speed of frozen-thawing patch was faster than that of samples between the grass patches.There was a significant negative correlation between the quantity of frozen-thawing patch and those of soil organic carbon/nitrogen contents and carbon/nitrogen storages.There was a significant positive correlation between the size of frozen-thawing patch and those of soil organic carbon/nitrogen content and carbon/nitrogen storage(P<0.01).These results indicate that there are significant differences in soil carbon/nitrogen content and carbon/nitrogen storage among different degrees of degradation in alpine wetland.The quantity is indicative and it is recommended to strengthen the water supplement and the protection of the frozen-thawing mound in alpine wetlands.