高寒草原生态系统表层土壤活性有机碳分布特征及其影响因素——以贡嘎南山-拉轨岗日山为例

对贡嘎南山-拉轨岗日山南坡高寒草原生态系统表层(0～20cm)土壤活性有机碳分布特征研究表明:表层(0～20 cm)土壤活性有机碳平均为(2.4986±0.7864) g/kg,占表层土壤有机碳的(12.7926±21.00)%.在海拔4424～4804m范围内,随着海拔升高,表层(0～20cm)土壤活性有机碳含量表现出先减少后增加的分布特征,有机碳活度也表现出先减少后增加的分布特征.影响表层土壤活性有机碳含量最关键的环境因子是地上生物量、0～10cm地下生物量、30～40cm地下生物量、20～30cm土壤含水量、0～20cm土壤容重、20～40cm土壤容重和土壤全N量;影响表层土壤有机碳活度最关键的环境因子则是植被盖度、20～30cm地下生物量、0～10cm土壤含水量、10～20cm土壤含水量、20～30cm土壤含水量、土壤有机质、土壤速效K和土壤全N量.

Influential factors and distribution characteristics of topsoil labile organic carbon

The distribution characteristics of the topsoil (0-20cm) labile organic carbon of alpine grassland ecosystem at the south slope of Gongga south mountain-Laguigangri mountain were studied. The results showed that, the average content of the topsoil (0-20cm) labile organic carbon was (2.4986±0.7864) g/kg, accounting for (12.7926±21.00)% of the topsoil organic carbon in alpine grassland ecosystem at the south slope of Gongga south mountain-Laguigangri mountain. With increasing altitude, the distribution characteristics of the topsoil (0-20cm) labile organic carbon and organic carbon lability were decrease→increase within the altitude range of 4424-4804m. The key environmental factors influencing the content of topsoil labile organic carbon were overground biomass, biomass of underground 0-10cm and 30-40cm, moisture of underground 20-30cm, soil bulk density of underground 0-20cm and 20-40cm, and soil total Nitrogen content. However, the key environmental factors for the topsoil (0-20cm) organic carbon lability were vegetation coverage, 20-30cm belowground biomass, 0-10cm,10-20cm and 20-30cm underground soil moisture, soil organic matter, soil labile Potassium and soil total Nitrogen content.