Department of Environmental Science, Policy, and Management, University of California, Berkeley, California 94720, United States.
Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
Environ Sci Technol. 2021 Oct 5;55(19):13345-13355. doi: 10.1021/acs.est.1c00300. Epub 2021 Sep 24.
Minerals preserve the oldest, most persistent soil carbon, and mineral characteristics appear to play a critical role in the formation of soil organic matter (SOM) associations. To test the hypothesis that roots, and differences in carbon source and microbial communities, influence mineral SOM associations over short timescales, we incubated permeable mineral bags in soil microcosms with and without plants, inside a CO labeling chamber. Mineral bags contained quartz, ferrihydrite, kaolinite, or soil minerals isolated via density separation. Using C-nuclear magnetic resonance, Fourier transform ion cyclotron resonance mass spectrometry, and lipidomics, we traced carbon deposition onto minerals, characterizing total carbon, C enrichment, and SOM chemistry over three growth stages of . Carbon accumulation was rapid and mineral-dependent but slowed with time; the accumulated amount was not significantly affected by root presence. However, plant roots strongly shaped the chemistry of mineral-associated SOM. Minerals incubated in a plant rhizosphere were associated with a more diverse array of compounds (with different functional groups-carbonyl, aromatics, carbohydrates, and lipids) than minerals incubated in an unplanted bulk soil control. We also found that many of the lipids that sorbed to minerals were microbially derived, including many fungal lipids. Together, our data suggest that diverse rhizosphere-derived compounds may represent a transient fraction of mineral SOM, rapidly exchanging with mineral surfaces.
矿物质保留了最古老、最持久的土壤碳，并且矿物质特性似乎在土壤有机质（SOM）的形成中起着关键作用。为了验证以下假设，即根以及碳源和微生物群落的差异会在短时间内影响矿物质 SOM 的形成，我们在带有和不带有植物的土壤微环境中，将可渗透的矿物质袋放在 CO 标记室中进行培养。矿物质袋中含有石英、水铁矿、高岭石或通过密度分离获得的土壤矿物质。使用 C 核磁共振、傅里叶变换离子回旋共振质谱和脂质组学，我们追踪了碳在矿物质上的沉积，对总碳、C 富集和 SOM 化学进行了表征，研究了. 的三个生长阶段。碳的积累是快速且依赖于矿物质的，但随着时间的推移会减缓；根的存在对积累量没有显著影响。然而，植物根系强烈影响矿物质结合 SOM 的化学性质。在植物根际中培养的矿物质与在未种植的大量土壤对照中培养的矿物质相比，与更多种类的化合物（具有不同功能基团-羰基、芳烃、碳水化合物和脂质）相关联。我们还发现，许多吸附在矿物质上的脂质是微生物衍生的，包括许多真菌脂质。总之，我们的数据表明，多样的根际衍生化合物可能代表矿物质 SOM 的一个短暂部分，与矿物质表面快速交换。
