In the battle to mitigate global warming farmers’ nitrogen use will be scrutinized

But soil scientist Mario Tenuta says there are things farmers can do to help themselves

Mario Tenuta, professor of applied soil ecology at the University of Manitoba predicts, among other things, that anhydrous ammonia and urea — popular nitrogen fertilizers — will be banned because they produce too much nitrous oxide — a powerful greenhouse gas.

The fight to control global warning will bring about big changes in how Manitoba farmers farm, says Mario Tenuta, professor of applied soil ecology and chair and adviser of the B.Sc. Agroecology Program at the University of Manitoba.

“I predict eventually they will outlaw anhydrous ammonia and urea and replace it with high-efficiency (nitrogen) fertilizer,” Tenuta said in an interview Oct. 6. “That’s down the road, but that is a certainty in my mind. They can’t do it right now. They will probably come out and say these products just emit too much N2O (nitrous oxide) and we are banning them. We do things like that with things that pollute the environment.”

Nitrous oxide comes from nitrogen fertilizer and as a greenhouse gas is 300 times more potent than carbon dioxide.

Canadian provinces are working to put a price on greenhouse gas emissions so fewer are produced.

The Keystone Agricultural Producers (KAP) expects Manitoba will impose a tax on emissions. Not only does Tenuta expect such a tax to be levied on natural gas used to make nitrogen fertilizer, he predicts a carbon tax will be imposed on nitrogen retailers who will pass the cost onto farmers.

“To tell you the truth that’s what needs to happen,” he said.

But there could be options for farmers to avoid, or pay less of the tax. For example, farmers could get a discount if they have been certified under the 4R fertilizer stewardship program that teaches farmers to manage nitrogen to reduce losses. The four Rs are: the right source of fertilizer for the crop, the right rate to match nutrient supply with crop requirements, applying at the right time so nutrients are there when crop needs them and applying in the right place so the crop gets it.

Higher prices for urea and anhydrous also make Super U and ESN — types of nitrogen fertilizer, which are more expensive, but produce much less nitrous oxide — more attractive.

The Nitrous Oxide Emission Reduction Protocol (NERP) program offered through the 4R program could also save farmers money when a carbon tax is introduced, Tenuta said.

“Our research is showing there are benefits from reducing (nitrogen-related) emissions,” Tenuta said. “You can improve your yields from just using the nitrogen better. There are reasons for doing this stuff. It is just common sense and employing the right practices.”

Governments should also give farmers subsidies to buy equipment for banding their nitrogen, which reduces nitrous oxide losses, he said.

“By 2030 every farmer will be using intelligent fertilizers,” Tenuta predicted. “They will be applying them with high-tech equipment — not just broadcasting on the surface and walk away. You’re going to see practices change and I think that is for the better for the environment and for the grower economically in the end.”

Tenuta isn’t optimistic about farmers getting credits by sequestering carbon.

“The only way you are going to do carbon sequestration and get a credit for it is by putting forest on your agricultural land or if you’re going to put cropland into pasture it is going to have to be pasture forever,” he said. “I would never, ever as a farmer request carbon credits for carbon sequestration because I lose the right to use my land as I see fit. If you do something to that land and the carbon comes out of it I now have to pay back.”

Farmers won’t have too much trouble cutting greenhouse gas emissions 30 per cent from 2005 levels by 2022, Tenuta said. It’s going to be harder cutting 50 per cent by 2050 and being carbon neutral by 2080.

“Imagine the revolution that is going to be required in agriculture to be carbon neutral?” he said “We’re not going to have animals. We are going to have lab-grown meat. And then the fertilizers are going to be super-high-tech forms of nitrogen fertilizer. We won’t be using natural gas to produce nitrogen fertilizers; we will be using hydroelectricity (to make hydrogen through hydrolysis). Northern Manitoba could just have fertilizer factories.”

The world needs carbon neutrality to prevent overheating, Tenuta said.

“You just can’t keep producing more,” he said. “We are changing the constituents of the atmosphere.

“In my mind there is no option for this. Think of all the things we used to do. In cities people used to crap into a bucket and throw it out the window into the street. We got diseases and people realized you can’t do that.”

There have been more recent success stories, such are vastly curtailing acid rain, created by sulphuric acid emissions, which were destroying forests and lakes.

About the author


Allan Dawson

Allan Dawson is a reporter with the Manitoba Co-operator based near Miami, Man. Covering agriculture since 1980, Dawson has spent most of his career with the Co-operator except for several years with Farmers’ Independent Weekly and before that a Morden-Winkler area radio station.



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