This collection consists of the model set-up used to develop an initial capability for modelling biological nitrification inhibition (BNI) in APSIM Next Generation and a preliminary evaluation of BNI in wheat, canola, sorghum and maize systems across Australian grain regions. To generate the data, an extensive literature review of BNI was undertaken. Based on the available evidence, an APSIM-BNI module was developed using APSIM Manager script and integrated into APSIM. The APSIM-BNI module was evaluated for model sensibility, parameter sensitivity and uncertainty. The developed APSIM-BNI module was then used in a scenario analysis to quantify the plausible impact of BNI on both productivity and emissions from Australian farming systems. This collection includes APSIMX file with BNI manager script, simulation output in csv formats. The output variables reported either daily, seasonal or annual include soil carbon, soil mineral nitrogen, nitrogen loss pathways, soil water, crop biomass, N uptake yield, and gross margins. Lineage: Simulations were performed using APSIM Next Generation v.2025.8.7828.0 sites across the grain regions of Australia. Soil data were retrieved from the APSOIL database. Historical climate data is provided by the SILO. The BNI model parameters integrated into APSIM were based on extensive review of available literature