Rhizosphere priming regulates soil organic carbon and nitrogen mineralization: The significance of abiotic mechanisms

•Low-N soil had higher RPEs and relative primed N than high-N ones.•The RPEs and relative primed N were higher in high-Fe than low-Fe oxides soil.•Biotic process was reflected in increased microbial biomass and enzyme activity.•The abiotic process was responsible for C exchanged between root-C and Fe-SOC.•Biotic–abiotic mechanisms regulated soil C and N mineralization in the rhizosphere.