Mrs. Kakali Roy1, Dr. Brian Wilson1,2, Dr. S.M.F. Rabbi3
1University Of New England, Faculty of Science, Agriculture, Business and Law, Armidale, Australia, 2NSW Office of Environment and Heritage, PO Box U221, Armidale, Australia, 3University of Sydney, Camden, Australia
Carbon storage in the soil is believed to be an effective way to sequester atmospheric carbon and abate the impact of climate change. Water soluble carbon in the soil can be adsorbed and stabilised on the clay surfaces. The mechanisms of translocation and stabilisation in this way are complex and require detailed investigation. The sorption and stabilisation of dissolved organic carbon (DOC) is dependent on the DOC concentration, clay content and mineralogy of the soil. We undertook a batch sorption experiment using DOC extracted from a C4 plant to explore the sorption of the added DOC in three soils (i.e. Dermosol, Chromosol and Ferrosol) with contrasting mineralogy. The concentration and isotopic signature of soluble and adsorbed carbon were determined, and the maximum sorption capacity of the soils were modelled. Initial DOC concentration and soil mineralogy both had significant effects on the DOC sorption and our results have significance for the long-term storage of carbon in soils, particularly in the deeper, clay rich horizons.