Quantifying and correcting for pre-assay CO<sub>2</sub> loss in short-term carbon mineralization assays

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