The rate of substrate-induced CO2 production is converted to total microbial biomass by the conversion factor. The compounds oxidized during the process of respiration are called respiratory substrates. based on the response of microbial respiration to the addition of glucose and the absence of a response of root respiration. Measure fungal, bacterial and total microbial contributions to glucose-induced respiration and the potentially active microbial biomass on decaying plant residues of differing composition. The microbial biomass carbon is calculated using the difference between the fumigated and un fumigated EOC values, divided by a conversion factor kckc​. The conversion factor kckc​ typically used is 0.45 for carbon.