Theoretical model of the abiotic component of soil 13CO2 tracer efflux in 13C pulse-labeling experiments on plant-soil systems

► First model of abiotic soil 13CO2 tracer efflux in 13C pulse-labeling experiments. ► Analytical and numerical model predictions of amount of abiotic tracer component. ► Numerical model predictions of time distribution of soil abiotic tracer efflux. ► Only two soil model parameters: soil diffusion coefficient and retardation factor. ► Models provide guidance for reduction of interference from abiotic component.