Vizza, C., M. Belanger, G. P. Robertson, and S. S. Roley. 2021. Quantifying and correcting for pre-assay CO2 loss in short-term carbon mineralization assays. Dryad, Dataset https://doi.org/10.5061/dryad.fj6q573rf .
The active fraction of soil organic carbon is an important component of soil health and often is quickly assessed as the pulse of CO2 released by re-wetting dried soils in short-term (24−72 h) assays. However, soils can lose carbon © as they dry and if soil samples vary in moisture content at sampling, differential C loss during the pre-assay dry-down period may complicate the assay’s interpretations. We examined the impact of pre-assay CO2 loss in a long-cultivated agricultural soil at initial moisture contents of 30, 50, and 70% water-filled pore space (WFPS). We found that 50 and 70% WFPS treatments lost more C during drying than did those in the 30% WFPS treatment, and that dry-down losses led to a 26−32% underestimate of their CO2 pulses. We developed a soil-specific correction factor to account for these initial soil moisture effects. Future C mineralization studies may benefit from similar corrections.
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