海拔梯度对川西高寒土壤轻组分有机碳动态影响研究

作为土壤活性有机碳主要组分之一的轻组分有机碳（LFOC），对高海拔和高纬度低温生态系统的土壤有机碳动态及稳定性具有重要意义。通过在西南亚高山—高山海拔梯度上（3 250，3 438，3 672，3 852，4 098 m）对亚高山森林土壤均质化后进行原位培养，研究高寒土壤中轻组分有机碳在海拔梯度上的响应特征与季节变化趋势。结果表明:海拔升高及低温季节均有利于土壤LFOC积累，而生长季节是土壤LFOC的消耗时期；在同一采样时间的同一海拔高度上，表层（0—10 cm）和表下层（10—20 cm）土壤LFOC含量总体表现出随深度增加而降低的规律，其中在低温季节中后期的11月和3月均达到差异显著水平。

Temporal Dynamics of Light-Fraction Organic Carbon of Subalpine-Alpine Soil Along an Altitudinal Gradient in the Southwestern China

The soil light fraction organic carbon (LFOC) as one of the main components of soil labile organic carbon is of significance for dynamics and stability of the soil organic carbon in the cryogenic ecosystems of high altitude and high latitude area. Repacked columns of homogenized topsoil (0—20 cm) were incubated along a altitudinal gradients (3 250 m,3 438 m,3 672 m,3 852 m,4 098 m) in subalpine-alpine area of southwestern China. By analyzing response characteristics and trends of soil light fraction organic carbon (LFOC) the 0—10 cm and 10—20 cm depths in the elevation gradient, seasonal dynamics of soil light fraction organic carbon (LFOC) and its related biochemical processes under temperature gradient caused by different altitudes were revealed. The results showed that elevation and cold seasons are conducive to the accumulation of soil LFOC but the growing season is the consumption period of soil LFOC. All content of soil LFOC decreased with increase of depth in soil layer of 0—10 cm and 10—20 cm at the same elevation of the same sampling time, which presents the significant difference levels in November and March.