Capturing carbon in Australian soils: potential and realities.

An interest exists to enhance the amount of carbon contained in Australian soils because of the beneficial impacts on both soil productivity and atmospheric concentrations of greenhouse gases. There is no doubt that Australian soils have the capacity to capture additional carbon by altering current management practices. However, much debate remains over the potential rate and magnitude of carbon capture. It is unlikely that capturing carbon within soil will offset Australia’s net greenhouse gas emissions, but it is likely that soils can contribute to reducing emissions within a broader set of strategies. A review of Australian research trials comparing traditional agricultural management practices with practices designed to retain addition carbon has indicated that, irrespective of the management practices applied, soil carbon values have continued to decline under agricultural production. However, the extent of SOC reduction was reduced under more conservative carbon friendly practices. This would result in an avoided emission, when compared to the business as usual scenario, rather than a net sequestration of carbon from the atmosphere. In an effort to extend our understanding of the magnitude of soil carbon change under different land use/management practices at a regional scale, a national soil carbon project has been recently established. This program will sample soils from the major combinations of soil and land use/management practices within defined regions across Australia. Land use/management impacts on differences in both the amount and composition of soil carbon will be defined.