Soil Organic Carbon Turnover Modelling with 'C-TOOL' // Provides an 'R' interface to the 'C-TOOL' soil carbon turnover model for simulating soil organic carbon dynamics in agricultural systems. The package supports the definition of carbon inputs, management schedules, soil parameters, and temperature forcing, and includes tools for scenario analysis and calibration of selected model parameters against observed soil organic carbon stocks. The 'C-TOOL' model and related modelling framework are described by Petersen et al. (2002) doi:10.1016/S0304-3800(02)00034-0, Petersen et al. (2005) doi:10.1016/j.soilbio.2004.08.006, Petersen et al. (2013) doi:10.1016/j.jclepro.2013.03.007, and Taghizadeh-Toosi et al. (2014) doi:10.1016/j.ecolmodel.2014.08.016. Further applications and developments are described by Taghizadeh-Toosi et al. (2016) doi:10.1016/j.agsy.2016.03.004, Keel et al. (2017) doi:10.1111/ejss.12454, Taghizadeh-Toosi et al. (2020) doi:10.1007/s11104-020-04500-9, and Taghizadeh-Toosi and Christensen (2021) doi:10.1038/s41598-021-97744-z.