Abstract

Soil organic carbon management is a nature-based carbon dioxide removal technology at the same time contributing to soil health and agricultural productivity. The soil science communities are refuting the traditional assumptions of the nature of soil organic matter (SOM) as based on ‘humic substances’ that are operationally-defined and have not been observed by contemporary, in situ spectromicroscopic techniques. Instead, new theories suggest that the interactions between molecular diversity of organic compounds, their spatial heterogeneity and temporal variability controls the formation and persistence of SOM. A mechanistic understanding of these processes occurring within organo-mineral and organo-organic assemblages requires non-invasive techniques that minimize any disturbance to the physical and chemical integrity of the sample. Here, we present a theory-driven review where a combination of in situ methods serve as potential solutions to better understand the persistence and dynamics of SOM and its effects on nutrient distribution at a micro- and nano-scale. We explore underlying theories in light of advances in available methodologies, their historical development and future opportunities. Examples of interdisciplinary approaches that have been utilized in other areas of science but not in soils offer both deductive and inductive analytical opportunities. We show how different conceptual methods across scales inform each other, and how important and indispensable high-resolution investigations are to resolving next-generation questions.

摘要

土壤有机碳管理是一种基于自然的二氧化碳去除技术，同时有助于土壤健康和农业生产力。土壤科学界正在驳斥关于土壤有机质（SOM）性质的传统假设，该假设基于“腐殖质”，这些“腐殖质”是在操作上定义的，并且未被当代原位观察到光谱显微镜技术。相反，新理论表明有机化合物的分子多样性、它们的空间异质性和时间变异性之间的相互作用控制了 SOM 的形成和持续存在。对有机矿物和有机有机组合中发生的这些过程的机械理解需要非侵入性技术，以最大限度地减少对样品物理和化学完整性的任何干扰。在这里，我们提出了一个理论驱动的评论，其中结合了原位方法可作为潜在的解决方案，以更好地了解 SOM 的持久性和动态及其对微米和纳米尺度养分分布的影响。我们根据现有方法的进步、它们的历史发展和未来机遇探索潜在的理论。已在其他科学领域但未在土壤中使用的跨学科方法的示例提供了演绎和归纳分析的机会。我们展示了不同尺度的不同概念方法如何相互影响，以及高分辨率调查对于解决下一代问题的重要性和不可或缺性。