3D-organisation of the solid, pore and organic phases in soil microaggregates and its control on mechanical stability

土壤微团聚体中固体、孔隙和有机相的 3D 组织及其对机械稳定性的控制

• 批准号: 276973637
• 负责人: Professor Dr. Stephan Peth
• 金额: --
• 依托单位: Fachbereich 11 - Ökologische Agrarwissenschaften
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/276973637?language=en
• 关键词: 3D; organisation; solid; pore; organic

Soil structure is the expression of a complex spatial arrangement of solids (organic and inorganic matter) and pores, which are variably filled with water and gas. A plethora of soil functions such as the supply of nutrients and water, sequestration of carbon, transformation of pollutants or simply the functioning of soil as a habitat for soil organisms depend on soil structure. Despite of the importance of aggregates as building blocks that sustain soil structure related functions, initial aggregate formation is still poorly understood. In the frame of the research unit 2179 (Mad Soil: Microaggregate development in Soil) this subproject investigates physical key processes involved in soil aggregation to support the development of a mechanistic understanding of aggregate formation. We study the dynamics of soil micro-aggregate formation and turnover by applying modern experimental approaches and analytical tools such as X-ray tomography (University of Kassel), Synchrotron tomography (HASYLAB), quantitative 3D image analysis and physicochemical microsensing to obtain quantitative links between micro-aggregate architecture und its influence on biotic and abiotic processes leading to aggregate formation. In the first phase of the research unit we will focus on a toposequence (clay content gradient) and a multi-isotope labelled microcosm experiment. The main research question in this context is how soil structure evolves as a function of clay content and how this influences the interaction of physical (water and oxygen transport) with biological (microbial activity, EPS) processes and the resulting mechanical stability of micro-aggregates (e.g. by creating low entropy stable structures). The 3D images will be analyzed to obtain morphological and structural information. This will enable us to quantify not only the pore space, but also the spatial organization of pores and solid phases of these building blocks. The results will be correlated with physical properties obtained from microscale soil measurements (e.g. oxygen microdiffusion, SOM location, mechanical stability) which will enhance our understanding of the role of physical processes in aggregate formation and provide input data for the development of a mechanistic quantitative model of micro-aggregate formation (subproject PM).

土壤结构是固体（有机和无机物质）和孔隙的复杂空间排列的表达，孔隙中充满了水和气体。土壤的多种功能，例如养分和水的供应、碳的封存、污染物的转化，或者仅仅是土壤作为土壤生物栖息地的功能，都取决于土壤结构。尽管团聚体作为维持土壤结构相关功能的构件的重要性，但初始团聚体的形成仍然知之甚少。在研究单元2179（疯狂的土壤：土壤中的微团聚体发展）的框架下，该子项目研究了土壤团聚体中涉及的物理关键过程，以支持对团聚体形成的机械理解的发展。我们研究了土壤微团聚体的形成和营业额的动态应用现代实验方法和分析工具，如X射线断层扫描（卡塞尔大学），同步辐射断层扫描（HASYLAB），定量的三维图像分析和物理化学微传感，以获得微团聚体结构及其对生物和非生物过程的影响，导致团聚体形成之间的定量联系。在研究单元的第一阶段，我们将侧重于地形序列（粘土含量梯度）和多同位素标记的微观实验。在这方面的主要研究问题是土壤结构如何演变为粘粒含量的函数，以及这如何影响物理（水和氧气运输）与生物（微生物活性，EPS）过程的相互作用以及由此产生的微团聚体的机械稳定性（例如通过创建低熵稳定结构）。将分析3D图像以获得形态和结构信息。这将使我们能够不仅量化孔隙空间，而且量化这些构件的孔隙和固相的空间组织。这些结果将与从微尺度土壤测量（例如氧微扩散，SOM位置，机械稳定性）获得的物理性质相关，这将增强我们对物理过程在团聚体形成中的作用的理解，并为微团聚体形成（子项目PM）的机械定量模型的开发提供输入数据。