These data are from an investigation of the effects of biochar application to soil, on soil greenhouse gas emissions and N transformations within the soil. Biochar is a carbon rich substance which is being advocated as a climate mitigation tool to increase carbon sequestration and reduce nitrous oxide emissions. The data were collected during a 15N pool dilution incubation to investigate the nitrogen transformations within biochar-amended soil following the addition of 15N-labelled ammonium nitrate. Analyses included 15N content of nitrous oxide and 15N content of soil. The N transformations were then modelled using a model for calculating nitrogen fluxes in soil using 15N tracing (FLUAZ model).