Three recently reported case pstudies reveal significant increases in soil carbon are possible in Australian soils. This contradicts the misinformation published by the GRDC and others:
Cam McKellar, “Inverary Downs”, Spring Ridge NSW: An increase of 0.59% SOC between March and November, 2008 in a cropping enterprise.*
Brian Kreig, “Kreigfields” Snowtown SA: An increase in SOC of 1.17% in 3 years in a broadacre cropping environment.**
Michael, Noel and Marie Moretti, “Roselea” Biloela QLD:An increase of 0.57% SOC in pasture cropping environment.***
An increase in soul carbon was recorded on grazing and cropping land from 2% to 4% recorded on “Winona”, Gulgong, between 1995 and 2005.
Dr K Yin Chan, Principal Research Scientist (Soils), NSW Department of Primary Industries, has a research project which has stretched over 20 years. In the soils studied, he found that there was on average 70 tonnes of soil carbon per hectare under undisturbed native vegetation. This fell dramatically to 40 T/ha under conventional tillage by the 1940s. It rose 5T/ha under Reduced Tillage, to 45T/ha. Dr Chan believes we can recover the (25T/ha) balance. He calls it the "Soil C Sequestration Potential".
“Permanent unimproved pastures in moister areas of NSW, SA, WA and Qld, after sowing to introduced grasses and legumes and fertilised with superphosphate have been shown to exhibit linear increases in soil C at a rate of about 0.4 t C ha-1 yr-1 over several decades. ****
Barrow (1969) reported a soil C gain of 440 kg/ha/yr in sandy soils under permanent pasture during a period of 30-40 years in Western Australia. The pasture outscored undisturbed native vegetation on soil C by 2.0% to 0.8%.*****
* Australian Farm Journal, May 2010
** LaurieCo Biological Farming Systems Soil Carbon Tour Handbook, May 2010
***Australian Farm Journal, April 2010
**** Gifford RM, Cheney NP, Noble JC, Russell JS, Wellington AB and ZamitC (1992) Australian land use, primary production of vegetation and carbon pools in relation to atmospheric carbon dioxide concentration. pp151-187 in Australia’s Renewable Resources, Sustainability and Global Change. Roger M. Gifford and Michele M. Barson (Eds) Publ Bureau of Rural Resources and CSIRO Division of Plant Industry. Quoted in “Pasture improvement for potential additional C-sinks for inclusion under the Kyoto Protocol”, by Roger M. Gifford, Damian J. Barrett and Andrew Ash for the Biosphere Working Group of the CSIRO Climate Change Research Program, 30 April, 1998b
***** Barrow, N. J. 1969. The accumulation of soil organic matter under pasture and its effect on soil properties. Australian Journal of Experimental Agriculture and Animal Husbandry 9:437-445.
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