They proposed that this decrease was caused by C limitation and the inhibition of
microbial activity by volatile compounds. We propose that
the increased pH in BC added soil should not negatively
affect methanogen activity as pH range for metabolism of
methanogens are near neutral to alkali. In contrast, we
suggest that the step from C mineralization to utilizable C
substrate such as LOC is the main limiting step on methanogenesis
(CH3COOH to CO2 + CH4; and CO2 + 4H2 to CH4 +
2H2O). It should therefore be investigated further.