环青海湖区退化芨芨草群落的土壤碳密度特征

通过对环青海湖区退化芨芨草群落的土壤容重和有机碳含量的测定分析,确定了退化芨芨草群落的土壤碳密度特征。结果显示,重度退化芨芨草群落的土壤容重显著大于中度退化芨芨草群落的土壤容重。重度退化芨芨草群落土壤有机碳含量普遍低于中度退化芨芨草群落,特别是两者表层土壤有机碳含量差异极为显著(p0.001)。在0—100cm剖面上,中度退化芨芨草群落土壤有机碳含量总体呈减少趋势,重度退化的则呈现减少和先增加后减小的两种变化趋势。芨芨草群落土壤有机碳密度跟有机碳含量变化趋势一致;芨芨草群落土壤有机碳主要集中在0—30cm土层,中度和重度退化下该深度土壤有机碳密度分别为7.35和2.92kg/m2,占整个剖面有机碳密度的57.45%和63.06%;环青海湖区中度和重度退化芨芨草群落剖面土壤有机碳密度为12.79和4.63kg/m2。

Characteristics of Soil Organic Carbon Density in Degraded Achnatherum Splendens Communities Around Qinghai Lake

Based on measurements of soil bulk density and organic carbon content, this paper studied the characteristics of soil organic carbon density in degrading Achnatherum splendens communities around the Qinghai Lake. Results showed that soil bulk density under the heavily degraded Achnatherum splendens communities was apparently greater than that in the moderately degraded communities. Soil organic carbon content in the moderately degraded Achnatherum splendens communities was generally higher than that in the heavily degraded. Especially, there existed an extreme apparent difference in surface soil organic carbon content between them. In the 0-100 cm soil profile, soil organic carbon content showed a decreasing trend in the moderately degraded Achnatherum splendens communities and however, the heavily degraded communities displayed two kinds of trend, i.e., decreasing trend and the trend of first increasing and then decreasing with soil depth. Soil organic carbon density showed the same trend as its content. Soil organic carbon was mainly distributed in the 0-30 cm soil layer. Soil organic carbon densities in the layer in the moderately and heavily degraded Achnatherum splendens communities were 7.35 and 2.92 kg/m², respectively, occupying 57.45% and 63.06% of the total soil organic carbon densities in the whole soil profile. In the profiles, soil organic carbon densities in the moderately and heavily degraded Achnatherum splendens communities around the Qinghai Lake were 12.79 and 4.63 kg/m², respectively.