Modelling SOC response to land use change and management practices in sugarcane cultivation in South-Central Brazil

To study the impact of land use change (LUC) from native vegetation and pasture to sugarcane cultivation as well as to evaluate the effect of different management practices on long-term SOC dynamics using the CENTURY ecosystem model. A soil data set of 85 study areas including sugarcane, pasture and annual crops from eleven counties distributed over the south-central region of Brazil was used for model validation and three future scenarios of sugarcane management were simulated: i) green harvesting (SC1); ii) green harvesting plus organic amendments (SC2) and iii) green harvesting plus low N inputs (SC3). Sugarcane harvest with burning was simulated as the baseline system (SCB). The model performance was good (R-2 = 0.79) in replicating measured C stocks as well as reflecting the main trends of C stock changes due to LUC. Long-term simulations suggested that changes in the sugarcane harvest from burning to green harvesting would increase soil C stocks by an average of 0.21 Mg ha(-1) year(-1). The potential of C accumulation was projected to be higher when vinasse and filter cake are added to the soil, varying between 0.34 and 0.37 Mg C ha(-1) year(-1) in SC3 and SC2 respectively. The Century model can be used as tool to study the impact of different soil managements in the SOC dynamics in sugarcane. C losses due to the conversion from pasture to sugarcane can be totally restored after 24, 17 and 18 years under SC1, SC2 and SC3, respectively.