Rapid and Cost-Effective Method for Soil Carbon Mineralization in Static Laboratory Incubations

We evaluated a modified approach for carbon (C) mineralization using a single-cell infrared gas analyzer (IRGA). Objectives were to (i) determine if IRGA, gas chromatography (GC), and alkali absorption of carbon dioxide (CO₂) in sodium hydroxide (NaOH) have similar results over 21 days; (ii) determine how these methods correlate; (iii) estimate the limit of quantitation (LOQ); (iv) compare throughput times; and (v) estimate the concentrations of CO₂ and oxygen (O₂) that suppress respiration. IRGA did not differ from the GC and NaOH results over 21 days. Coefficients of determination (R²) for IRGA, GC, and NaOH had values of 0.92 or more. IRGA and GC had the lowest LOQ (115 and 90 ppm CO₂), with the greatest LOQ (600 ppm CO₂) found with NaOH. IRGA had the fastest sample throughput (150 h^–1), followed by 17 and 10 h^–1 for GC and NaOH, respectively. Average suppression concentrations were 5.3% for O₂ and 10.5% for CO₂.