Stable carbon isotope fractionation, carbon flux partitioning and priming effects in anoxic soils during methanogenic degradation of straw and soil organic matter

► Determination of δ13C in CH4, CO2 and acetate from degradation of straw. ► No difference in methanogenic degradation of rice straw versus maize straw. ► Partitioning of C flux from degradation of straw versus soil organic matter. ► Priming effect of straw on methanogenic degradation of soil organic matter.