黑河上游山地青海云杉林土壤有机碳特征及其影响因素

Characteristics of Soil Organic Carbon under Picea crassifolia Forest and Relationship with Environmental Factors in Upper Reaches of Heihe River

以黑河上游祁连山中段青海云杉林为研究对象,分析了不同林区云杉林表层（0~20 cm）土壤有机碳的分布特征及其与气候因子、植被特征和土壤特性的关系。结果表明：祁连山中段3个林区青海云杉林表层土壤有机碳含量为寺大隆林区[（9.38±0.72）%]〉西水林区[（7.81±0.43）%]〉大河口林区[（6.06±0.30）%],土壤有机碳含量平均值为（7.41±0.28）%,变异系数为37.9%。土壤有机碳含量与海拔、土壤含水量、土壤全氮呈显著正相关关系,而与土壤pH值呈显著负相关关系。经主成分分析表明,海拔和土壤pH值是影响土壤有机碳含量的第一主成分,土壤全氮是第二主成分,云杉林密度是第三主成分,累计解释率为72.47%。

Soil organic carbon is an important component of terrestrial carbon pool, its storage and fluxes play major roles in the globe budget of carbon. This paper aims to analyze the distribution patterns of soil organic carbon （SOC） in Picea crassifolia forest in upper reaches of Heihe River and to determine which factors affect those patterns. The research was carried out in Da-Hekou （D）, Xi-Shui（X） and Si-Dalong（S） woodlands which locate in middle of Qilian Mountain. The results indicate that SOC has significant difference in the above three woodlands, that is （9.38±0.72）% in S〉（7.81±0.43）% in X〉（6.06±0.30）% in D, and the averagec SOC content in top soil （0±20 cm） is （7.41±0.28）%. Correlation analysis shows that the SOC content is positively correlated with altitude, soil water content, soil nitrogen content and C/N, and negatively correlated with soil pH. Further principal component analysis shows that altitude and soil pH are the first principal components affecting SOC content, followed by the soil nitrogen content and density of Picea crassifolia forest, which account for 72.47 % of the variance of SOC content.