Toil to improve soil - Weekly Times Now

Genevieve Barlow

May 5, 2010

FORMER farmer Russell Burnett is developing a machine that he hopes will produce biochar to build soil carbon content.

The graduate microbiologist, who worked as a food technologist before farming around Finley in southern NSW for 24 years, has invested almost three years and about $500,000 to build his prototype biochar producer.

AT A GLANCE
Who: Russell Burnett
What: Biochar
Why: Striving to make it work
Where: Bendigo, Victoria
Report: GENEVIEVE BARLOW
Biochar is charcoal produced at high temperatures without oxygen in a process called pyrolysis.

The appeal of Russell's invention is its broad diet, anything from animal manures through to car tyres, that he says can be converted to a more stable form of carbon.

Though lifeless, the highly porous biochar or charcoal is thought to stop fertilisers from leaching and also attract soil-dwelling microbial life (bacteria and fungi).

Russell said mychorrizal fungi, for example, which live on plant roots feeding nutrients into plants seemed to take to it like fish to water.

He thinks it could maximise the effectiveness of soluble fertilisers and even help cut the volumes of fertiliser required.

Trials on sugar cane in northern NSW are testing biochar's impact on nitrogen use from applied urea.

Closer to home, trials on biochar's effect on soil structure, yield and soil carbon have been set up at Hopetoun, Carwarp, Elmore, Clunes and Mathoura.

The first year of the Clunes trial on wheat plots compared the effects of applying zero biochar and 100kg/ha DAP with one tonne/ha of biochar and no DAP, 2.5 tonnes/ha of biochar and no DAP and five tonnes/ha and no DAP. Each approach was replicated three times.

"The aims are threefold," Russell said.

"To determine the long effect on soil structure of a once-only application of biochar, to determine how a once-only application of biochar may reduce the long-term requirements of high analysis soluble fertilisers and the compounding effect of adding biochar on soil's carbon content."

Russell said it might take years to show any impact.

"We're hoping to show that, using biochar, farmers could halve or even reduce by two-thirds the amount of soluble fertilisers such as DAP and MAP that they use."

He said adding biochar could also be an asset for farmers wanting to enter the carbon market.

His idea was sparked by a BBC documentary The Secret of El Dorado which highlighted archaeological evidence of Amazonians building loamy soils in inhospitable rainforest using charcoal.

"It just made a lot of common sense," Russell said.

"I know from my own experience as a farmer that when charcoal was left behind after burning, the growth in the paddock was better.

"The plants love it. The soil microbes love it," Russell said.

Bendigo soil scientist Christian Bannan is monitoring plant growth and crop yields on the trial sites.

He said research overseas had shown that biochar increased the soil's water-holding capacity and improved soil structure by allowing greater aeration, water infiltration and root elongation.

But these benefits were yet to be officially proven in Australia.

"In our trials we found that generally five tonne/ha of biochar yielded more than 100kg/ha of DAP but at this stage that's impractical (for costs reasons)," Christian said.

"In the long term we might apply one tonne/ha of biochar a number of times to achieve a 20 per cent increase in yield every year whereas DAP's impact is exhausted every year."

Russell is refining his machine in a Bendigo industrial estate shed where his company Biochar Energy Systems operates.

He's been working closely with Northern Poultry Cluster Ltd, a group of poultry producers and processors hopeful of adding value to poultry manure and possibly using the energy generated during pyrolysis.

"None of this is rocket science, but we're just trying to keep things simple," Russell said.

He said there were others working on biochar plants in Australia and around the world but were asking a lot of money for facilities that processed two to three tonnes an hour.

"For a facility that does a tonne an hour you are looking at about $600,000."

Elmore farmer Frank Harney believes biochar is a vital tool for farmers in a climate of change.

"In Europe biochar is used but Australians are silly enough to burn their stubbles and let it go to waste," Frank said.

Commercialising Russell's small-medium scale biochar producer might face some challenges like: how much is biochar worth, how much is needed to improve soil health and how much of the energy produced is saleable?

Meanwhile, his belief in biochar's benefits for farming country is unshakeable.

"I've played around with it myself and it always works."