The “Critical Zone” (CZ) is defined as the Earth's permeable near-surface layer from the tops of the trees to the bottom of the groundwater, placing soils in a central position and role in CZ structure and function. Studying soil organic matter (SOM) cycling within the framework of CZ science involves linking small/molecular scale understanding of SOM dynamics to larger temporal and spatial scales. OM production, decay, mineralization, transport and persistence in soils thus must be examined in the context of concurrent, dynamic and bidirectional relationships with weathering and other surface and sub-surface processes. We will highlight how SOM research and CZ science combine to shape an evolving paradigm for evaluating how various soil state factors, soil forming processes, and ecosystem features contribute to OM cycling in soils. Presentations will encompass diverse CZ systems (agriculture, temperate and tropical forest, mountain, wetland), and reach beyond the typical confines of soil biochemistry and biology to embrace pedology, mineralogy, chemistry, physics and hydrology. We invite contributions from across these diverse disciplines who address SOM production, transformations, and fates, and especially encourage contributions from those working across a range of temporal or spatial scales.