Abstract Stabilization of organic matter (OM) against decomposition and its de-stabilization leading to mineralization, are important processes in the control of greenhouse gas emissions and carbon sequestration in soils. Soil organisms, particularly earthworms, may influence these processes greatly through their potential impacts on the interaction of OM with clay minerals, which is a mechanism which may protect OM for medium (years) to long (decades, centuries) time scales. The aim of this study was to use earthworms and pure minerals in order to investigate enhancement of carbon sequestration through the formation of aggregates containing particulate OM and organo-mineral associations, during a composting experiment. To this end we compared OM transformations in composting treatments with and without (i) clay minerals (montmorillonite) and (ii) epigeic earthworms (Eisenia andrei and Eisenia foetida). We used density fractionation of the end-products to quantify the amount of aggregates, including organo-mineral associations, formed during 196 days. Chemical composition and stability were examined by elemental analyses, Rock-Eval 6 thermal analysis and solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. The results indicated that the addition of minerals led to the formation of heavy fractions, most probably containing aggregates and organo-mineral associations, in treatments with and without earthworms. While OM showed higher oxidative transformation in all treatments, addition of earthworms changed organic carbon (OC) and nitrogen (N) concentrations in specific density fractions and increased the thermal stability of OM in heavy density fractions. These fractions contained higher proportions of aromatic and proteinaceous materials. We conclude that, earthworms under composting conditions, earthworms may be able to effectively to stabilize OM through the formation of aggregates and/or organo-mineral associations containing greater proportions of microbially-derived material.

中文翻译：

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通过 Rock-Eval 热解和 13C NMR 光谱推断蚯蚓对有机矿物组合稳定性的影响

摘要 有机质 (OM) 的稳定分解及其失稳导致矿化，是控制土壤中温室气体排放和固碳的重要过程。土壤生物，特别是蚯蚓，可能会通过它们对 OM 与粘土矿物相互作用的潜在影响来极大地影响这些过程，这是一种可以在中（年）到长（几十年、几个世纪）时间尺度内保护 OM 的机制。本研究的目的是使用蚯蚓和纯矿物质来研究在堆肥实验中通过形成含有颗粒 OM 和有机矿物组合物的聚集体来增强固碳。为此，我们比较了有和没有 (i) 粘土矿物（蒙脱石）和（ii）表生蚯蚓（Eisenia andrei 和 Eisenia foetida）的堆肥处理中的 OM 转化。我们使用最终产品的密度分级来量化聚集体的数量，包括在 196 天内形成的有机矿物组合。通过元素分析、Rock-Eval 6 热分析和固态 13C 核磁共振 (NMR) 光谱检查化学成分和稳定性。结果表明，在有和没有蚯蚓的处理中，矿物质的添加导致重馏分的形成，很可能含有聚集体和有机矿物组合。虽然 OM 在所有处理中都表现出更高的氧化转化，添加蚯蚓改变了特定密度部分的有机碳 (OC) 和氮 (N) 浓度，并增加了重密度部分中 OM 的热稳定性。这些馏分含有较高比例的芳香族和蛋白质类物质。我们得出的结论是，蚯蚓在堆肥条件下，蚯蚓可能能够通过形成包含更大比例的微生物衍生材料的聚集体和/或有机矿物结合物来有效地稳定有机质。