中文摘要：

沿自然原因和人为原因形成的水分梯度，对若尔盖高寒湿地沼泽土和泥炭土的有机碳（SOC）和活性有机碳（LC）进行了研究。研究表明，若尔盖高寒湿地沼泽土有机碳和全氮沿水分梯度（减小）变化趋势一致，即在表层0-10cm湿润环境中的有机碳和全氮含量远高于淹水环境和过渡地带，而10-30cm沿水分梯度差异变小。泥炭土的有机碳和氮素含量在湿润环境远大于淹水（流水）环境。这说明当时的挖沟排水疏干沼泽使得相当一部分土壤有机碳或者释放到大气中，或者随水流流失。沼泽土活性有机碳在表层0-10cm沿水分梯度升高；在10～30cm差异变小，与有机碳和氮素的变化趋势一致。泥炭土的活性有机碳沿水分梯度升高，与泥炭土有机碳和氮素变化趋势一致。这一方面反映了两种土壤类型成土过程的不同，另一方面也反映了自然原因和人为原因造成的差异。沼泽土的碳氮比沿水分梯度有降低的趋势而泥炭土的碳氮比沿水分梯度有升高的趋势。此外，高寒沼泽土碳氮比，pH值以及机械组成都是影响土壤有机碳，氮素和活性有机碳的重要因子。

英文摘要：

Contents of soil organic carbon （SOC）, total nitrogen （TN） and labile carbon （LC） along natural and artificial water table gradient were measured in two types of alpine wetlands of Ruoergai plateau, China, in 2004. Results showed that the distribution characteristics of SOC, TN and LC were very similar in swamp soils, increasing along natural water table gradient at surface 0-10 cm and decreasing gradually with soil depth. The distribution characteristics of SOC, TN and LC were very similar in peat soils, increasing greatly along artificial water table gradient at 0-30 cm, which indicated that a great deal of carbon was emitted to atmosphere or run off due to artificial drainage at that time. Contents of LC decreased in swamp soils and increased in peat soils with soil depth, which indicated that the different process of forming swamp soils and peat soils, and the effect of natural and artificial water table, The C/N ratios decreased in swamp soils and increased in peat soils along water table gradient. In addition, soil C/N ratios, pH values and soil particlesize contents were important factors affecting SOC, TN and LC in alpine wetlands.