A Canadian farmer, Gary Lewis, has developed 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 along with the seed. The exhaust gases stimulate microbial activity and root growth, allowing the plants to more efficiently extract nutrient and moisture from the soil.

Mr Lewis says that tractor exhaust has allowed him and other farmers working with his technology to grow excellent crops without using conventional fertilisers. He says that he has not used fertiliser on his 250-hectare irrigation farm for at least six years, yet he had seen no loss of production, his soils had moved from pH 8.0 (the same as his irrigation water) to a pH of about 7.0 and soil organic matter levels are now at about 10 per cent.

In addition to the savings in fertilizer, he sees potential income from carbon offsets through the process.

About 150 farmers around the world, including in Australia, Britain, South Africa and recently China, are trialling the technique.

Ian Linklater, who grows wheat on a 3,845 hectare property near the Murray River north of Mildura, was the first Australian farmer to test the system. He spent $20,000 customising equipment that cools his tractor’s exhaust fumes and injects them into the soil as he sows his crop. He says that he has saved around $500,000 in nitrogen and phosphorus fertilizers in the two years that he has been using the system.