Interactive Effect of Soil Pore Network Structure and Substrate Quality on Soil CO2 Production: a Combined X-ray CT Incubation Experiment

The role of soil structure in organic matter (OM) stabilization has been primarily investigated through physical fractionation studies operative at the scale of aggregates and smaller organo-mineral particles. By narrowing down soil structure to an arrangement of mineral and organic particles, the majority of studies did not explore the spatial organization of the soil pore network, the actual habitat of microorganisms. In a lab experiment we incubated a sandy loam soil (with application of ground grass or sawdust) in 18 small aluminum rings (O 1 cm, h 1 cm). Bulk density was adjusted to 1.1 or 1.3 Mg m -3 (compaction) and 6 rings were filled at a coarser Coarse Sand:Fine Sand:Silt+Clay ratio.