Organo-mineral associations are recognized as key factors in stabilizing organic matter within microaggregates and even larger structural units in soil. A better understanding of the mechanisms behind the formation and stabilization are essential to predict or manage soil
structure, fertility and organic matter dynamics. Recent studies point to the highly dynamic nature
of the structural units of soil, while the major interaction mechanisms, e.g. adsorption and
and coprecipitation, are strongly dependent on the environmental conditions. Microaggregates including the OM-associations may form, alter, and break up depending on the local milieu (i.e., the presence of minerals, redox conditions, pH, water content, type of organic molecules, biotic drivers, etc.), under natural and management-induced variations in soil. With the growing experimental and observational evidence of the existence and build-up of these sub-micrometer soil compounds, in turn the number of modeling approaches increase that aim for an advanced mechanistic understanding of the formation and stabilization processes, the resulting 3d-structures, and their role in the functioning of soil. With this session, we respond to the growing awareness and intensive debate of the importance of the sub-micrometer-architecture for the dynamics and functioning of soils. Presentations will focus on studies that investigate organo-mineral interactions up to the size of microaggregates in soil and sediments, including their time dependence, conceptual, analogic or numerical modeling, the spatial explicit characterization of organo-mineral associations down to the nanoscale through high-resolution imaging microscopies and spectroscopies, the impact of plant C input, the role of the soil fauna and microorganisms, as well as their potential to increase C storage in any types of ecosystem.

Note: This session is a merger of SSS5.6 "Organo-mineral association dynamics in soil" and SSS5.10 "Microaggregates in Soil"