Continental-scale soil carbon composition and vulnerability modulated by regional environmental controls
Continental-scale soil carbon composition and vulnerability modulated by regional environmental controls
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DOI：
10.1038/s41561-019-0373-z
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发表时间：
2019-07-01
影响因子：
18.3
通讯作者：
Richards, A.
中科院分区：
文献类型：
--
作者：
Rossel, R. A. Viscarra;Lee, J.;Richards, A.
土壤有机碳(C)是全球碳循环的重要组成部分。在大尺度上控制其组成和动力学的过程还没有得到很好的理解。因此，我们对碳循环的理解是不完整的，这使得很难预测由于气候、土地利用和管理的变化而导致的碳的损益。在澳大利亚，有机碳的组成、颗粒、腐殖质和抗性组分以及C对分解的潜在脆弱性的控制是不同的、依赖于尺度的和可变的。我们使用机器学习对5,721个表土测量结果表明，从大陆上看，气候、土壤性质（例如，总氮和pH值）和海拔是主要控制因素。然而，我们发现这样的一般评估忽略了影响有机C组分和脆弱性分布的潜在区域特异性控制。这可能会导致误解，从而影响我们对土壤C过程和动力学的理解。从区域来看，气候是通过与土壤性质、矿物学和地形的相互作用来调节的。在一些地区，气候没有影响。这些结果表明，需要对土壤碳动态进行区域评估，并对生物地球化学和地球系统模型进行更多的局部参数化。我们的分析建议制定针对特定区域的战略，以实现有效的碳管理和减缓气候变化。
Soil organic carbon (C) is an essential component of the global C cycle. Processes that control its composition and dynamics over large scales are not well understood. Thus, our understanding of C cycling is incomplete, which makes it difficult to predict C gains and losses due to changes in climate, land use and management. Here we show that controls on the composition of organic C, the particulate, humus and resistant fractions, and the potential vulnerability of C to decomposition across Australia are distinct, scale-dependent and variable. We used machine-learning with 5,721 topsoil measurements to show that, continentally, the climate, soil properties (for example, total nitrogen and pH) and elevation are dominant controls. However, we found that such general assessments disregard underlying region-specific controls that affect the distribution of the organic C fractions and vulnerability. This can lead to misinterpretations that prejudice our understanding of soil C processes and dynamics. Regionally, climate is mediated through interactions with soil properties, mineralogy and topography. In some regions, climate is uninfluential. These results highlight the need for regional assessments of soil C dynamics and more local parameterization of biogeochemical and Earth system models. Our analysis propounds the development of region-specific strategies for effective C management and climate change mitigation.