The sensitivity of issuing C-CO2 with respect to temperature presented significant correlation with the degree of humification, the content of phenolic groups and the formal potential of electrode of humic acids and fulvic acids. Thus, the greater sensitivity of issuing C-CO2 with respect to temperature will be linked to a lesser degree of humification of organic matter, i.e. higher c/n ratio; at a lower content of phenolic groups of humic substances; and a less formal electrode potential of humic acids and fulvic acids.