Testing Os Staining Approach for Visualizing Soil Organic Matter Patterns in Intact Samples via X-ray Dual-Energy Tomography Scanning
Testing Os Staining Approach for Visualizing Soil Organic Matter Patterns in Intact Samples via X-ray Dual-Energy Tomography Scanning
复制标题
测试 Os 染色方法，通过 X 射线双能断层扫描可视化完整样品中的土壤有机质模式
DOI：
10.1021/acs.est.0c01028
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发表时间：
2020
影响因子：
11.4
通讯作者：
Guber, Andrey
中科院分区：
文献类型：
--
作者：
Zheng, Hongbing;Kim, Kyungmin;Kravchenko, Alexandra;Rivers, Mark;Guber, Andrey
多孔材料中非颗粒有机物情景可视化的挑战限制了对有机化合物运输、分解和储存过程的理解和建模。特别是，它阻碍了破译驱动土壤有机质(SOM)积累和保护的机制，这些过程对于维持土壤肥力和减轻全球气候变化的影响至关重要。最近提出的一种用OsO4蒸气对土壤有机质进行染色并随后进行双能X射线计算机显微断层扫描(μCT)的方法，为在完整的土壤基质中可视化土壤有机质提供了新的机会。我们的目的是测试该方法在不同孔隙特征的介质中对不同有机物质的染色性能：(1)放置在细沙和粗沙中或生长在土壤微芯中的柳枝草(Panicum virgatumL.)根，(2)生物炭碎片，以及(3)相对低和高碳含量的土壤。我们发现，该方法对根来源的有机物和与土壤微粒有关的有机物是有效的，但对生物炭却不是。与OsO4蒸气反应的总碳的估计百分比从植物根部的0.7%到高碳土壤无沙部分的3.2%，而在所研究的生物炭中仅为0.2%。土壤总C和Os浓度之间有很强的线性关系，这暗示了未来方法发展的潜力。然而，我们建议在解释气体通过土壤基质的扩散有限的情况下解释结果时要谨慎。
Challenges within situvisualization of nonparticulate organics in porous materials limit understanding and modeling processes of transport, decomposition, and storage of organic compounds. In particular, it impedes deciphering the mechanisms driving accumulation and protection of soil organic matter (SOM), processes crucial for sustaining soil fertility and mitigating effects of global climate change. A recently proposed method of staining soil organics by OsO4vapors with subsequent dual-energy X-ray computed microtomography scanning (μCT) offers new opportunities to visualize SOM within intact soil matrix. Our objective was to test the method’s performance in staining different organic materials located in media with contrasting pore characteristics: (1) roots of switchgrass (Panicum virgatumL.), either placed within fine and coarse sands or grown within soil microcores, (2) biochar fragments, and (3) soils with relatively low and high C contents. We found that the method was effective in staining organic materials of root origin and the organics associated with fine soil particles, but not the biochar. The estimated percent of total C that reacted with OsO4vapors ranged from 0.7% in plant roots to 3.2% in sand-free fraction of the high C soil and was only 0.2% in the studied biochar. Total soil C and Os concentrations were strongly linearly related, suggesting a potential for future method development. However, we would recommend caution when interpreting the results in cases when gas diffusion through the soil matrix is limited.