Contribution of rhizodeposit associated microbial groups to SOC varies with maize growth stages

•Saprophytic fungi (SF) were important in processing 13C at vegetative stage (V12).•Actinomycetes (Ac) were dominant in processing 13C at reproductive stage (R3).•Contribution of 13C-MBC to 13C-SOC increased from 5% at V12 to 25% at R3.•Higher proportions of aryl C and O-alkyl C were observed at V12 and R3 respectively.•RDA analysis showed close associations between aryl C and SF, and O-alkyl C and Ac.