祁连山天老池小流域土壤有机碳空间异质性及其影响因素

Spatial Variability of Soil Organic Carbon and Its Relationship with Environmental Factors in Tianlaochi Catchment in Qilian Mountains,Northwest China

采用野外取样和室内分析，结合地统计学方法和方差分析方法，分析了祁连山天老池小流域0～30cm层的土壤有机碳的分布特征及其与植被类型、地形和土壤性质等因素的关系。结果表明，该流域土壤有机碳垂直分布存在显著的差异，随着土层深度的增加，土壤有机碳含量显著减少，0～10、10～20、20～30cm土层土壤有机碳含量分别为105．08、81．46、62．62g／kg，土壤平均有机碳含量为83．05g／kg，变异系数为0．56。不同的植被类型0～10cm土层土壤有机碳含量表现为青海云杉（138．20g/kg）〉灌丛（118．49g/kg）〉亚高山草甸（100．43g／kg）〉祁连圆柏（74．17g／kg）〉干草原（43．94g／kg）；随着海拔的升高土壤有机碳含量增加，阴坡有机碳含量明显高于阳坡；经相关性分析表明，土壤有机碳与土壤全氮和砂粒呈显著正相关关系，与土壤体积质量、黏粒和粉粒呈显著负相关关系。

The spatial variability of SOC content of 0-30 cm soil layer and the relationships with vegetation types, topography and soil characteristics in Tianlaochi Catchment in Qilian Mountains was analyzed by Kriging interpolation method and ANOVA. The results indicated that the average of SOC content was 83.05 g/kg, the coefficient of variation was 0.56. SOC had the significant vertical distribution, that is, SOC content decreased with increasing soil depth. The average SOC contents were 105.08, 81.46 and 62.62 g/kg in 0-10, 10-20 and 20-30 cm, respectively. The SOC contents under Qinghai Spruce, Shrub, Qilian Sabina, Subalpine meadow and Dry grasslands was 138.20, 118.49, 100.43, 74.17 and 43.94 g/kg in 0-10 cm, respectively. From 2 600 m to 3 600 m, SOC content increased with increasing altitude. SOC content was also different with the different slope aspect, the shady slope was higher than that in sunny slope. Correlation analysis showed that SOC content was positively correlated with total nitrogen and sand content, and negatively correlated with soil bulk density, clay and silt content.