Let tractors put carbon back into the ground

We are bombarded with suggestions about how we can reduce our “carbon footprint” and help save the planet, but a breakthrough by a Canadian farmer may have a real impact in reducing the discharge of greenhouse gases and, at the same time, effect considera

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We are bombarded with suggestions about how we can reduce our “carbon footprint” and help save the planet, but a breakthrough by a Canadian farmer may have a real impact in reducing the discharge of greenhouse gases and, at the same time, effect considerable savings on fertiliser. Joe Spencer reports.

According to the Canadian Company N/C Quest, 45 farmers in Canada, Australia and the US have successfully channelled tractor exhaust gases back into the soil in the 2007 season, providing extra fertiliser. This Alberta-based organisation, headed by farmer and soil scientist Gary Lewis, claims cooling exhaust gases such as carbon dioxide and channelling them back into the ground during sowing, via the airflow in pneumatic drills, increases soil microorganism activity by boosting soil carbon content. “Increasing carbon, and thus natural fertility, in this way saves farmers about half their usual fertiliser bill for cereals and oilseeds,” explains Gary. “It’s also helping reduce emissions of greenhouse gases. We say that about 95% of the exhaust gases of the tractor powering the drill, can be captured and applied in this way. Then of course there are the huge savings in gas emissions from the production and transport of the artificial fertiliser that is no longer applied.” Savings in fertiliser are indeed substantial, according to one large-scale grain producer in Canada.

Darrel Carlisle, who has 2 200ha of combinable crops around the town of Carroll in Manitoba, reckons he’s been able to reduce his fertiliser bill this year by the equivalent of about R2 million, using only half the amount used on conventionally fertilised fields. Full yield details weren’t available at the time of going to print, but Darrel says first signs indicate yields are at least as good as the long-term average with conventional fertilising in Manitoba. Trials in previous years have also seen yields staying level. Visit www.bioagtive.com or e-mail N/C Quest Inc at [email protected]

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Pic: Canadian Darrel Carlisle has developed his own electrically powered system for more efficient cooling of tractor exhaust gases before they are fed into the drill airflow. He has been testing the effect for three years now and estimates that, drilling at standard revs, he’s putting about 8kg/ha of carbon dioxide into the soil from his tractor engine. “We’ve been running official tests on soils and plant tissues, including grain, and analysing everything,” says Darrel, who adds that no toxins have yet been found. “The gases and minerals coming out of the smokestack is stuff that’s naturally in the ground anyway.” The equipment claimed to change exhaust gases into valuable fertiliser, and the licence for it, cost around R375 000. “But the savings on 600ha of crop could recoup this in a single season,” Darrel points out.