The Land

By Richard Fox

A move towards no-till based farming practices will help restore carbon in Australia's soils and help the country play a leading role in any future global carbon sequestration movement, according to some of the world's leading soil scientists.

Researchers from the US, England, France, New Zealand and Australia addressed an audience of farmers and industry specialists at the University of Sydney earlier this month and gave their backing to minimal cultivation farming techniques.

Minimal cultivation of soil increases the interaction between plants and soil and this creates more soil carbon, said Argonne National Laboratory senior scientist, Dr Julie Jastrow, Illinois. "Soil structure plays a strong role in carbon stabilisation and this is affected by consistent cultivation," she said. "In reality, soil carbon is a complex mixture of forms that we need to understand further." To help farmers across Australia adapt to no-till or minimal tillage techniques, a number of practical techniques and tips are to be developed by the scientists and research groups across the world.

Among the scientists' five-year goals, they aim to improve soil carbon predictions, create regional baselines for soil carbon and develop plant breeding programs that do not focus on yields alone. Further research on the impacts of no-till and other farming practices will be conduced in Australia and overseas. Moving from annual cultivation to perennial and zero tillage farming systerns is one of the most efficient ways to restore carbon in soils, said Colorado State University ecologist, Professor William Parton. Mr Parton, who has focused his research on the development of ecosystem models, said advances in machinery and minimal tillage farming systems make it easier for farmers to repair carbon depleted soils. "The roots of a plant are the primary source for soil carbon stabilisation and recent advances in soil models allow the prediction of soil carbon sequestration everywhere," Professor Parton said.

"To go from annual to perennial systems is one of the best and most efficient ways to restore carbon.

"We have been modelling on the question of how do different kinds of ploughs and machinery impact on soil structure and carbon interactions."

Improvements in knowledge and no till machinery mean increased soil carbon levels are now accessible to more Australian farmers than they were a decade ago, said CSIRO scientist, Jeff Baldock. "Agriculture provides both risks and opportunities to restore soil carbon," he said.

"What we should be doing as scientists is trying to produce a tool that will tell farmers whether a 50 per cent change in water use efficiency will increase carbon on their property or not."