Sequestering carbon dioxide in Australian soil will not provide a viable means of offsetting greenhouse gas emissions according to the latest research by scientists at the University of Melbourne.
The research, conducted by University of Melbourne scientists examined hundreds of studies in Australia over a period of three decades, and concluded that carbon storage in the soil is "technically limited and economically unviable at the present time."
Report co-author Rick Roush, Dean of the Melbourne School of Land and Environment, said storage of carbon in the soil would likely be limited to the top 10 centimetres of the earth and would be adversely impacted by poor nutrient levels and water scarcity.
"It's difficult to keep soil carbons accumulating when you continue to plough and cultivate annual crops," he said.
Roush further pointed out that soil is only capable of accumulating carbon at a gradual rate and that agricultural methods which foster the process, such as no-till farming, are already in widespread use in Australia.
The conclusions of the report published in the journal Nature Scientific Reports serves to undermine both the Carbon Farming Initiative, a project for encouraging soil-carbon projects which enjoys bipartisan support, and the Coalition's Direct Rival Action plan for reducing greenhouse gas emissions.
Under current carbon prices of $24.15 per tonne, farmers participating in the Carbon Farming Initiative would suffer loses of over $12 per tonne in area where normal soil conditions prevail.
These losses would likely be greater were a floating carbon price introduced in July next year as scheduled by the government.
The Coalition's Direct Action Plan appears even worse under the lens of the University of Melbourne study due to its focus on carbon soil storage as a key means of reducing green house gas emissions.
"The Coalition will use the Emissions Reduction Fund to deliver about 85 million tonnes per annum of CO2 abatement through soil carbons by 2020," the Coalition has said in an official statement.
The opposition has also called carbon farming "the single largest opportunity for carbon dioxide emissions reduction in Australia."
Roush said the Coalition's ambitious plans for carbon farming would fall far short of expectations.
"Our analysis showed that these strategies would result in only 53.3 million tonnes of CO2 equivalent sequestered in soil, and would therefore not meet the 85 million tonnes targeted in the Coalition's Direct Action Plan," he said.