When the smoke from a tractor exhaust goes up, that’s pollution. But get those emissions down into the soil and they become fertiliser, as Canadian farmer, Gary Lewis, is demonstrating.
Mr Lewis has spent the best part of a decade developing and refining a system that pipes tractor exhaust
emissions through a condenser and into the pneumatic system of air seeders, which then injects the carbon and nitrogen-rich emissions into the ground with the seed.
What is generally considered as pollution is in fact prime soil food, Mr Lewis said, and tractor exhaust has allowed him and other farmers working with his technology to grow excellent crops without using conventional fertilisers.
The exhaust gases are believed to stimulate microbial activity and root growth, allowing the plants to more efficiently extract nutrient and moisture from the soil.
The United Nations has shown an interest in the system, which might not only reduce fertiliser dependency but cut greenhouse gas emissions.
Mr Lewis, an Alberta rancher and former auto mechanic who specialises in growing timothy hay for export, claims not to have used fertiliser on his 250-hectare irrigation farm for at least six years, instead fertilising it with his “BioAgtive” technology.
Mr Lewis said he had seen no loss of production, his soils had moved from pH 8.0 (the same as the irrigation water) to a pH of about 7.0, and soil organic matter levels were now at about 10 per cent.
In testimonials quoted on the BioAgtive website, former Agriculture Canada scientists turned consultants, Dr Jill Clapperton and Dr Loraine Bailey, agree that something positive is happening in BioAgtive treated soils.
“The obvious conclusion is that the exhaust had a positive effect on crop growth, yield and quality, and may have positively enhanced soil nutrients and nutrient chemistry,” Dr Bailey writes.
Meanwhile, Dr Clapperton is working on a scientific paper outlining how the technology works.
Understanding why BioAgtive is not just “blowing smoke”, as Mr Lewis feels many scientists think he’s doing, requires a different perspective on exhaust emissions.
Surprisingly, a breakdown of the content of diesel exhaust looks like a partial Christmas shopping list for plants.
A Volkswagen analysis of light-duty diesel engine exhaust published in a World Health Organisation-sponsored report gave an analysis by weight of 75 per cent nitrogen, 15pc oxygen, seven per cent carbon dioxide and 2.6pc water vapour.
Several other substances existed in quantities of less than 0.1pc.
Mr Lewis calculates a zero-till rig will put 1100 kilograms of air through the tractor engine to work a hectare.
Dr Bailey writes that the exhaust treatment “resulted in significant release of soil N and/or stimulated the crops to take up soil N”.
She said there were also small increases in the uptake of phosphorus, potass-ium and sulphur and slight shifts in the amount of some micro-nutrients taken up by the crops.
If it proves viable, BioAgtive will also be a tool for farmers wanting to reduce their profile under emissions trading.
The system relies on attraction between negatively-charged ions in the gases and the soil’s positively charged alkaline component to hold the gases in the soil, as well as sealing it in.
Some Canadian farmers are now growing their own biofuel crops using BioAgtive technology, Mr Lewis said.
About 150 farmers around the world, including in Australia and recently China, had bought into the concept.
While the system doesn’t come cheap, at about $C40,000, Mr Lewis points to what he says is the potential to save hundreds of thousands of dollars in fertiliser in a year.
Gary Lewis is booked to talk at the Carbon Farming Conference and Expo at Orange, on November 4-5.
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