Dichotomy of gluing and cementing agents in soil microaggregation

土壤微团聚中胶结剂和胶结剂的二分法

• 批准号: 276973281
• 负责人: Professor Dr. Georg Guggenberger
• 金额: --
• 依托单位: Professur für Bodenkunde und Bodenschutz
• 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 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/276973281?language=en
• 关键词: Dichotomy; gluing; cementing; agents; soil

The identification of mechanisms in soil microaggregation is only possible by linking the surface chemistry of involved components to the formation and properties of microaggregates. We aim at identifying the role of different aggregate-forming agents (organic matter, clay minerals, metal oxides) involved in microaggregate formation and stability. For this, we will investigate the formation and temporal and spatial change of physicochemical properties of microaggregates (20-250 ¿m) and their building units (<20 ¿m) in a series of batch and microcosm experiments as well as in a soil toposequence. Our basic analytical approach relies on X-ray photoelectron spectroscopy (XPS) of microaggregates to determine the elemental composition of inorganic and organic surfaces. The microaggregate surface chemistry (XPS), morphology (scanning electron microscopy), particle and pore size distribution (laser diffraction, Hg porosimetry, gas adsorption), as well as wettability (contact angle analysis) will be related to the stability of microaggregates. Consequences of changing environmental conditions to microaggregate stability will be assessed upon selective removal of aggregate-forming agents via microbial reduction of FeIII oxides, organic matter mineralization, and pH shifts. These studies will provide a mechanistic background for modeling microaggregation with relevant implications for soil organic matter stabilization.

土壤微团聚体的识别机制，只有通过连接所涉及的组件的表面化学的微团聚体的形成和性能。我们的目的是确定不同的聚集体形成剂（有机物，粘土矿物，金属氧化物）参与微聚集体的形成和稳定性的作用。为此，我们将在一系列批处理和微观实验中以及在土壤拓扑序列中研究微团聚体（20-250 <$m）及其构建单元（<20 <$m）的理化性质的形成和时空变化。我们的基本分析方法依赖于微聚集体的X射线光电子能谱（XPS）来确定无机和有机表面的元素组成。微聚集体的表面化学（XPS），形态（扫描电子显微镜），颗粒和孔径分布（激光衍射，汞孔隙率，气体吸附），以及润湿性（接触角分析）将涉及到微聚集体的稳定性。通过微生物还原FeIII氧化物、有机物矿化和pH值变化选择性去除聚集体形成剂后，将评估环境条件变化对微聚集体稳定性的影响。这些研究将提供一个机制的背景建模微团聚体与土壤有机质稳定的相关影响。