How our soils became 'too old'

“Australian soils are too old and degraded to sequester significanct amounts of carbon.”

This statement was established at a 2000 workshop sponsored by the CRC on Greenhouse Accounting on sequestration. The report concluded that: “Australian climate, soils and agricultural management histories are significantly different to those of developed countries in the northern hemisphere. These differences generally result in considerably less potential for increase in soil carbon stocks associated with changing crop or pasture management practices in Australia compared with northern temperate regions.” .(1)

This conclusion was distilled in an official policy framework document as: “Typically Australian soils have a poor capacity to store large quantities of carbon." (2)

Even the Australian Farm Institute fell in behind the idea: "The bulk of Australian farms may not operate as carbon sinks, due to the age of the soils." (3) (The Institute corrected its position in the landmark report “The New Challenge for Australian Agriculture: How do you muster a paddock of carbon?”: “There are, however, potential opportunities that may arise for the farm sector to provide greenhouse offsets, which may generate income to counteract the anticipated additional costs.”)

The most definitive version of the myth was announced by the Grains Council: “Given the age and degraded nature of Australian cropping soils and the ‘natural’ low levels of organic carbon, there is no scientific evidence to suggest that there is a real possibility that organic carbon levels can be increased by cropping or farming practices at anything other than slow rates, reaching an equilibrium point well below that of northern hemisphere soils.” (4)

The Grains Council took to the airwaves in an energetic campaign to bury Australian soils: “Our soils are very old, very fragile, very thin, very weathered. Often we are running soils with 1% or less carbon.” (5)

NB. No research scientist made such statements.
NB. No scientific evidence has been given to support such statements.

Rebuttal:

• Sydney University Professor Alex McBratney – on hearing of this comment – said: “It’s misleading to say that because Australia has old soils there isn’t potential for enhanced sequestration of carbon in our soils.” - Alex. McBratney is Pro-Dean, Professor of Soil Science, Faculty of Agriculture, Food & Natural Resources, The University of Sydney

• Soils Officer with the Lachlan Catchment Management Authority Ian Packer said: " The people who make these remarks don't get around enough to know what's going on."

• Dr K Yin Chan, Principal Research Scientist (Soils), NSW Department of Primary Industries, believes we can recover the 25 tonnes per Ha of soil carbon lost since 1770. He calls it the "Soil C Sequestration Potential". (6)

• Generalisations about Australians soils are dangerous. Alpine soils can contain around 10% soil carbon, and desert soils around 0.5%. Soils tested for soils workshops with farmers at Mudgee and Rylstone have between 0.9% and 7% Carbon and averaging 2.2% at Mudgee and 2.7% at Rylstone. (7)

SOURCES:

1. Keenan, R., Bugg, A.L., Ainslie, H. (eds) (2000) Management Options for Carbon Sequestration in Forest, Agricultural and Rangeland Ecosystems. Cooperative Research Centre for Greenhouse Accounting, p. 1
2. Australian Greenhouse Office, Developing a Strategic Framework for Greenhouse and Agriculture. An Issues Paper, 2002
3. Keogh, M 2007, The New Challenge for Australian Agriculture: How do you muster a paddock of carbon?, discussion paper, Australian Farm Institute, Surry Hills, Australia.
4. “Carbon in Australian Cropping Soils: A background paper prepared by Alan Umbers For the Grains Council of Australia.” July 10th 2007
5. Alan Umbers, Grains Council, ABC Radio Country Hour, 11 July, 2007
6. Presentation at DPI farmers’ gathering at Junee Reef, 21 June, 2007.
7. Private conversation, Soils Coordinator, Central West Catchment Management Authority, July 2006