Potential of sugarcane farming systems in the Lower Burdekin to sequester soil carbon

Carbon farming is the process of changing farming management to sequester atmospheric carbon in soil or plants or reducing carbon emissions from agriculture. The Australian and Queensland Governments have carbon farming initiatives such as the Queensland Land Restoration Fund and the Australian Government’s Emissions Reduction Fund that are designed, in part, to promote or incentivise changes in farming practices to increase carbon sequestered in soils. These initiatives represent an opportunity for farmers to earn additional income and for income diversification. In this study, simulation modelling is used to predict changes in soil carbon due to changes in sugarcane management for a typical farm in the Lower Burdekin. It uses the sugarcane modelling framework developed for the Paddock to Reef Integrated Monitoring, Modelling and Reporting Program (P2R) which uses the Agricultural Production System sIMulator (APSIM) with inputs including a soil parameterised from the Queensland Government’s Soil and Land Information (SALI) database, historical climate data and, sugarcane management elicited from workshops with local experts and from aggregated survey data collected for P2R. For a modelled farm, we estimate a carbon sequestration rate of 1.3 kg/ha/year for 25 years, reaching a maximum of 127 kg/ha after 70 years, which are generally consistent with recent published experiments, and with no significant effect on cane production. Using the most recent spot price for a tonne of atmospheric carbon abatement, this rate of sequestration has an economic value of $18.50/ha/year, which does not include any cost incurred from changes in management.