青藏公路对沿线草地生态系统土壤可溶性有机碳及其特征的影响

可溶性有机碳(Dissolved organic carbon，DOC)是陆地生态系统碳循环的关键物质，为研究公路对沿线土壤DOC的影响，本试验以距G109格尔木至拉萨段公路不同水平距离(20 m，100 m，400 m)土壤为研究对象，测定土壤DOC含量，结合紫外可见光谱和三维荧光光谱分析土壤可溶性有机质(Dissolved organic matter，DOM)的光谱特征。结果表明：在同一海拔高度下，公路显著影响了土壤DOC分布的空间格局，距公路不同距离土壤DOC含量由高到低依次为：400 m > 100 m > 20 m；公路影响了土壤的芳香化程度和疏水性组分，距离公路越近，土壤有机质越不稳定；结合荧光特征指数得出，土壤DOM主要属于微生物源输入，且腐殖化程度较低。因此，对公路周边环境进行生态修复时，要特别注意距离公路较近处，可以通过提高植被覆盖度的方式，增加土壤碳储量及稳定性，保护生态环境。

Effects of the Qinghai-Tibet Highway on Soil Dissolved Organic Carbon Content and Characteristics in Grassland Ecosystems along the Route

Dissolved organic carbon (DOC) is a key substance,which could significantly affect the terrestrial carbon cycle. In this study,we aimed to examine the effects of the Qinghai-Tibet Highway on soil DOC contents and characteristics in grassland ecosystems along the route. The DOC content was determined at different horizontal distances (20 m,100 m,400 m) from the Golmud to Lhasa section of the G109 highway. The chemical characteristics of dissolved organic matter (DOM) were analyzed in ultraviolet-visible spectroscopy and three-dimensional fluorescence spectroscopy. Results showed that the spatial pattern of DOC content was significantly affected by the highway at the same altitude,and the DOC content decreased from high to low at different distances from the highway as:400 m > 100 m > 20 m. The highway could affect the degree of aromatization of the soil and hydrophobic component, and soil organic matter was relatively unstable at the sites closer to the highway. Combined with the fluorescence characteristic index,the DOM was mainly derived from the input of microbial sources and the degree of humification was low. Therefore,when ecologically restoring the surrounding environment of the highway,increased vegetation coverage can be used for sites with a closer distance,which will be of benefit to the increase of soil carbon storage and stability and protecting the ecological environment.