SUPPORTERS call it innovative, while critics describe it as bizarre.
Either way, both will be taking notice of the results of Australia's first trial of a tractor exhaust emissions recycling system on dryland grain crops near Mildura in Victoria.
The system's Canadian inventor Gary Lewis claims that injecting a stream of cooled exhaust gases into cultivated soil will enrich its fertility by boosting carbon and nitrogen levels.
This will encourage microbes that consume greenhouse gases and convert them into plant nutrients.
In turn, this will reduce fertiliser use, soil acidity and the amount of carbon dioxide entering the atmosphere.
Ian and Daniel Linklater, who farm near Trentham Cliffs, east of Mildura, heard about the revolutionary ideas from a friend.
"Out of the blue, a mate of ours was working for him (Gary) in Canada and came back to Australia and wanted to explore the idea," Daniel said.
"It went from there."
After Gary flew to Australia in March to give a presentation, the Linklaters decided there was no harm in trying it for themselves.
"It's fascinating what he's been able to achieve," Daniel said.
"Whether it will be replicated here, we'll soon know."
The pair spent about $25,000 modifying existing equipment and building some new components, with the help of a $10,000 grant from the Lower Murray Darling Catchment Management Authority.
The system uses a heat exchanger with two large fans that cool the exhaust to ensure it is no hotter than 30C, which might affect the seed's ability to germinate.
They then sowed their entire 3840ha crop of yitpi and sunvale wheat using the Lewis method, leaving only a trial plot, being managed by Mallee Sustainable Farming, for comparison.
MSF extension officer Dr Nicole Dimos said the Linklaters' aim was to promote biological activity in the soil and try to address the common problem of phosphorous and calcium lock-up.
"But it's not an alternative to fertiliser," she said.
"The Linklaters will continue to do soil audits every year and assess whether they need to apply conventional or non-conventional products."
Ian said the gamble had already paid off in one sense: it had saved them an estimated $300,000 in fertiliser costs this season.
Daniel said the only noticeable difference was the new equipment required the tractor to travel at a "slightly slower" speed while sowing.
"There's been a lot of interest in what we're doing," he said.
"There's been a lot of scepticism as well, as you'd expect.
"It's something that people want to see and touch and have a look at, but it's only an experiment.
"We'll be looking forward to harvesting when we can actually see whether there are some benefits.
"If the results are there, fantastic, if they're not, well we've had a lot of fun."
Daniel said the crops had been terrific until "the rain stopped" in September.
After a tough past few weeks, yields were now expected to reach one to 1.2 tonnes a hectare at most.
Ian started sharefarming on the property in the 1980s, when he converted it from a sheep station to cropping.
He bought it in 1991 and is in his 10th year of continuously cropping wheat.
Daniel, who worked for the Australian Barley Board for several years, returned to the farm last November.
Gary's invention, which was patented in 2006, has prompted spirited debate among users of online forums, with one wag warning the only sequestration to occur would be money into a salesman's pockets.
According to the Bio-Agtive website, the system costs $US12,500-$22,500 (plus taxes) and there is a $US15,000 upfront licence fee, as well as a $US1500 annual fee.
For more information visit CO2Xchange and Bio-Agtive.
