祁连山不同草地类型区土壤有机碳组份的差异

Differences of Soil Organic Carbon Components in Different Grassland Types of Qilian Mountain

为明确高寒地区土壤有机碳库的组成及稳定程度,选择祁连山地区3种草地类型区(高寒草甸、高寒草原和高寒沼泽草甸)为研究对象,分层对0~50 cm土壤中重组、轻组组分进行分离提取,测定并分析重组有机碳(heavy fraction organic carbon,HFOC)和轻组有机碳(light fraction organic carbon,LFOC)含量.结果表明,不同草地类型对土壤HFOC和LFOC含量及其分配的影响不同,HFOC、LFOC含量在土层间均具有明显的垂直变化,呈上高下低趋势,各区域间差异明显;高寒沼泽草甸LFOC含量最高,高寒草原次之,高寒草甸最低,即不同草地类型区土壤有机碳库稳定程度大小依次为:高寒草甸>高寒草原>高寒沼泽草甸;土壤pH、含水率、TC、SOC、TN含量与C/N值与土壤HFOC、LFOC含量呈极显著相关(p<0.01).综上,祁连山草地生态系统土壤有机碳库组成及稳定程度受草地类型、土壤理化性质及环境变量影响.

In order to determine the composition and stability of soil organic carbon pool in alpine areas,different grassland types(alpine meadow,alpine steppe and alpine swamp meadow)in Qilian Mountain area were selected as the research objects,the heavy and light components in 0-50 cm soil were separated and extracted by layer,and the contents of heavy fraction organic carbon(HFOC)and light fraction organic carbon(LFOC)were determined and analyzed.The results show that the effects of different grassland types on the content and distribution of soil HFOC and LFOC were different,the contents of HFOC and LFOC had obvious vertical changes among soil layers,show the trend of high and low,and there were obvious differences among different regions.The order of LFOC content in different grassland types is alpine swamp meadow>alpine steppe>alpine meadow,The order of soil organic carbon pool stability in different grassland types is alpine meadow>alpine steppe>alpine swamp meadow.Soil pH,moisture content,TC,SOC,TN content and C/N value were significantly correlated with soil HFOC and LFOC content(p<0.01).In summary,the composition and stability of soil organic carbon pool in Qilian grassland ecosystem were affected by grassland types,soil physical and chemical properties and environmental variables.