Use of carbon isotope composition for characterization of microbial activity in arable soils

The effect of glucose on microbial mineralization of soil organic matter (SOM) was studied in arable soil specimens. The fluxes of carbon dioxide generated during this degradation were deduced from differences in the carbon isotope abundance ratios of glucose (delta(13)C=-11.4 per mil) and SOM (delta(13)C=-27.01 per mil). The priming effect of glucose and respiratory quotient (RQ) were taken as indices of activation of SOM-consuming microbiota. The data on microbial mineralization of organic matter in soil obtained in this study show that the addition of a readily consumable substance (glucose) to soil favors SOM degradation and increases the release of carbon dioxide from soil to atmosphere.