Fig. 3. Recovery (percentage of added NaH¹⁴CO₃) of ¹⁴CO₂ following the addition and incubation of a ¹⁴C-labeled bicarbonate (NaH¹⁴CO₃) solution (0.001, 0.01, and 0.1 µmol g^-1 soil) in a high pH calcareous Typic Rendoll (T. Rend.) or low pH Typic Fragiochrept (T. Frag.) soil. Hydrogen chloride (1 M) was added to the soil after 6 h (denoted by arrow). Values represent means ± standard error of the mean, n = 3