E.A. Meier1, P.J. Thorburn1, N.P. Dumbrell2, J. Palmer1, J.S. Biggs1, M.E. Kragt3
1 CSIRO Agriculture and Food, 306 Carmody Rd, St Lucia Qld 4067, www.csiro.au, email@example.com
2 Centre for Global Food and Resources, The University of Adelaide, 10 Pulteney St, Adelaide SA 5005
3 University of Western Australia, 35 Stirling Highway, Perth WA 6009
Australian agriculture is a significant source of greenhouse gas (GHG) emissions and finding low cost abatement opportunities will allow this sector to contribute to GHG mitigation efforts. Biophysical and whole-farm economic modelling was used to predict GHG abatement, crop yields and farm profitability under different management practices and current and projected climates for representative case study farms (a total of 76 management-farm combinations) in Australia’s grain growing regions. A range of management practices (38 of the 76 combinations) could reduce GHG emissions, but there were substantial differences in the profitability of practices that delivered abatement. Of the 38 management-farm combinations that reduced GHG emissions, 11 were predicted to increase whole-farm profitability. However, the management scenarios that provided the most abatement tended to have the highest operating costs. For the 27 combinations where reduced GHG emissions came at reduced farm profits, the cost of abatement in most was greater than the average price paid for abatement from the Emissions Reduction Fund (ERF) to date. Reductions in nitrous oxide (N2O) emissions from soils were most important for net abatement on farms in the northern grains regions; increasing soil organic carbon (SOC) was most important for abatement at farms with low rainfall and sandy soils (predominantly the western grain region). Including ungrazed improved pastures in crop rotations was an option for abatement that maintained or increased profitability for sites. Reducing N2O emission becomes more important relative to SOC sequestration for achieving abatement over longer times (e.g. 100 years). These conclusions are likely to be valid under projected future climates.