Assessment of soil organic carbon (SOC) concentration in high-altitude shrublands is essential for understanding C dynamics in terrestrial ecosystems. Hence, we investigated the SOC concentration and its influencing factors using 198 soil profiles (0–100 cm) from 66 sites between 2011 and 2013 in the north-eastern Tibetan Plateau shrublands. SOC concentration was different under different shrubland types, with SOC concentration significantly greater in the alpine shrublands relative to the desert shrublands, whereas SOC concentration showed limited increases with altitude. Both mean annual temperature (MAT) and mean annual precipitation (MAP) have positive relationships with SOC concentration, and their relationships are moderate. Compared with MAT, a correlation between MAP and variation in SOC concentration was larger. Meanwhile, with increasing soil depth, a correlation between variation in SOC concentration and climatic factors was smaller. Soil pH seems to be a robust factor that not only had a significant negative correlation with SOC, but also played an important role in regulating a correlation between climatic condition and variation in SOC concentration. Controls on variation of SOC concentration on the Tibetan Plateau help to understand soil C dynamics in terrestrial ecosystems.

中文翻译：

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青藏高原东北部灌丛土壤有机碳浓度变化的控制

评估高海拔灌木地土壤有机碳 (SOC) 浓度对于了解陆地生态系统中的碳动态至关重要。因此，我们使用 2011 年至 2013 年间青藏高原东北部灌木地 66 个地点的 198 个土壤剖面（0-100 cm）调查了 SOC 浓度及其影响因素。不同灌丛类型下SOC浓度不同，高山灌丛SOC浓度显着高于荒漠灌丛，而SOC浓度随海拔升高有限。年平均气温（MAT）和年平均降水量（MAP）均与 SOC 浓度呈正相关，且关系中等。与 MAT 相比，MAP 与 SOC 浓度变化之间的相关性更大。同时，随着土壤深度的增加，SOC浓度变化与气候因素之间的相关性变小。土壤 pH 似乎是一个强大的因素，它不仅与 SOC 呈显着负相关，而且在调节气候条件与 SOC 浓度变化之间的相关性方面也发挥了重要作用。控制青藏高原 SOC 浓度的变化有助于了解陆地生态系统中的土壤碳动态。