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    Categories: Agriculture

Making food for food

INGREDIENTS FOR GROWTH – Common examples of fertilizer found at Sturgeon Valley Fertilizer. Clockwise from the upper left are ammonium sulphate

If you ate food today, you probably have fertilizer to thank for it.

And if it was grown locally, there’s a good chance that fertilizer came from André Montpetit.

“My great-grandfather homesteaded where my dad lives today,” says the Legal-area farmer.

Back then, farmers got most of their fertilizer from the back end of their own animals, he explained. But today’s intensive agriculture requires a more concentrated source of nutrients.

As manager of Sturgeon Valley Fertilizer, Montpetit sells thousands of tonnes of fertilizer to county farmers each year, most of it stored in a long red warehouse just northwest of the Hwy. 2/37 overpass. He’ll have up to 8,000 tonnes of the stuff crammed into three-storey tall silos in the lead-up to spring seeding, and almost all of it comes from the Agrium Redwater Fertilizer plant. Located across the road from the Sturgeon Refinery east of Gibbons, it’s the biggest fertilizer plant in Canada.

Agrium’s Mike Fedunec gave the Gazette a tour of the place recently.

“It’s complicated, making fertilizer,” he says, with lots of massive tanks, twisted pipes, and exotic catalysts involved.

But it all comes down to four simple letters: N, P, K and S.

How to spell growth

Farmers invest huge dollars into fertilizers each year as they typically double their yield doing so, Montpetit says. He ran out of fertilizer on one of his wheat fields this year, and it’s now about three inches shorter than the rest of his crop.

“I can see that strip from half a mile away.”

Fertilizer involves macro and micronutrients, Montpetit says. Micronutrients are elements such as boron or copper, which are typically made in the U.S. and needed in very small quantities.

Most of what you get in a commercial bag will be pellets or crystals of nitrogen (N), phosphorous (P), potassium (K) and sometimes sulphur (S) compounds, Montpetit says.

Nitrogen makes plants big and green, and is by far the most heavily used fertilizer around here, Montpetit says. Sulphur helps with plant growth and nitrogen absorption, and is particularly important for canola. Phosphorous helps with root growth, and potassium keeps crops upright.

Assembling the alphabet

Plants can’t use these nutrients directly, says Connie Nichol, environmental scientist with Agrium – their atoms are bound to each other and not available for reaction. Fertilizer factories convert these elements into forms that plants can utilize.

About 500 people work in shifts at the Redwater plant each day to crank out about 1.4 million tonnes of nitrogen, 610,000 tonnes of phosphorous, and 340,000 tonnes of sulphur fertilizer a year, Fedunec says – about 67 kg per Canadian. The whole process is controlled by a handful of operators from two explosion-proof bunkers full of computer screens and light-up alarm panels that wouldn’t look out of place on a nuclear submarine.

Almost all of the reactions to make these fertilizers happen inside high-temperature and pressure tanks and pipes.

Nitrogen fertilizer starts with natural gas and a five-storey rusty brown hunk of pipes, pumps and towers called the reformer, Fedunec says, as he drives past it.

In this building, steam reacts with natural gas in catalyst-filled pipes to create hydrogen and CO2. The hydrogen, along with airborne nitrogen, goes into a reaction tower under high heat and pressure to create ammonia, which has to be cooled to -33 C so it becomes liquid. Redwater typically cranks out about 1,800 tonnes of ammonia a day, Fedunec notes.

While some farmers will use liquid ammonium for their nitrogen, many prefer their fertilizer as more manageable urea granules.

The urea plant is full of tangled pipes, giant tanks and the deafening roar of fans. Here, CO2 made in the reformer reacts with ammonia in a 120-foot tall reactor tower to create liquid urea. The urea sprays into a spinning steel tank the size of a bus called a granulator until it dries to form little white pellets, which then zip along a conveyor to a storage shed the size of a strip mall.

Sulphur starts with molten sulphur from Fort McMurray, Fedunec says – about 30 trucks a day worth. Burn it in the presence of vanadium pentoxide and add water, and you get everyone’s flesh-melting favourite, sulphuric acid. Throw ammonia at that, and you get much-less lethal ammonium sulphate you can run through a granulator to produce whitish crystals.

That sulphuric acid is also used to make phosphorous. The Redwater plant hauls in a million tonnes of sand-like, tan-coloured phosphate rock a year from a surface mine in Morocco, Fedunec says.

Inside a green-striped building, the rock and acid flow through a series of tanks to create phosphoric acid and gypsum crystals (used in chalk and wallboard). Filter out the crystals, add ammonia to the acid, run the mix through a granulator, and you get round, brown bits of monoammonium phosphate ready to ship.

Potassium isn’t processed at Redwater. Instead, the red potassium chloride (potash) crystals used by farmers comes from a mine near Vanscoy, Sask., that’s three Empire State Buildings underground.

Up to 400 trucks a day haul fertilizers to distributors such as Sturgeon Valley Fertilizer, filling Montpetit’s silos right to the catwalks. Crews raise a wall at the bottom of the silos to let material out, and use a loader to scoop it into computer-controlled hoppers to create the blend a customer needs. Drop the mix in your seed drill, and it’s ready to use.

Expensive consequences

Montpetit says fertilizer costs about $50 to $100 an acre, depending on the crop, and most farmers grow 1,500 to 4,000 acres. He dropped about $200,000 of fertilizer on his farm this year alone – big operations like Tappauf Farms often spend millions.

“Fertilizer’s expensive. You just don’t want to put extra where it’s not required.”

There are environmental costs as well. The Redwater plant emits about 1.3 megatonnes of greenhouse gas emissions a year, Fedunec reports – equivalent to 1.8 St. Alberts. Fertilizer runoff from fields can promote algal blooms in lakes and rivers, while excess nitrogen can vaporize to become nitrous oxide – a gas with 298 times the warming potential of CO2.

And then there’s the gypsum.

Right next to the Redwater plant is the gypsum stack – a 45 million tonne ziggurat of white crystals that’s about 10 storeys tall and, at 650 acres, slightly bigger than Bon Accord. The heavy trucks and backhoes crawling on it look like Micro-Machines in comparison.

“To make a tonne of phosphoric acid, we end up with five tonnes of gypsum,” Fedunec explains.

Gypsum slurry gets piped to huge lakes atop the pile to settle out into a concrete-like solid. Pipes, ditches and a liner catch the acidic runoff for reuse in the plant.

While this gypsum can be used to make drywall, roads, or spill absorbent, it’s so heavy and acidic that most companies find it cheaper to mine new gypsum instead, Fedunec says. As such, it’s been piling up at Redwater and fertilizer plants around the world for decades.

“We get over a million tonnes a year,” he says, and there’s currently no viable use for it.

While she personally uses the stuff in her garden (it makes great potatoes and carrots), Nichol says the main way to dispose of gypsum is to cover it with dirt and plants. Crews have planted about 30,000 trees atop the old stack in Fort Saskatchewan, for example, and that forest is growing phenomenally well.

The Redwater plant made many energy efficiency improvements back in the early 2000s to reduce its greenhouse gas emissions and now buys about $1.6 million in carbon credits from the province to offset its emissions, Fedunec says. At this point, there aren’t many ways left to shrink the plant’s carbon footprint other than to scale back production.

Farmers spend months planning their fertilizer use to make it as efficient as possible, Montpetit says. They’ll use soil tests to determine what nutrients are needed and GPS and seed drills to place just those amounts next to each seed. Some use polymer-coated slow release urea (which is a pale green in colour) to reduce nitrogen loss to the air and water.

While organic farmers have turned away from artificial fertilizer altogether, Montpetit says they’re still a niche market and don’t have the capacity to produce the world’s food supply.

“We need fertilizer to grow mass amounts of food,” he says.

“We need to feed the world.”

Kevin Ma: Kevin Ma joined the St. Albert Gazette in 2006. He writes about Sturgeon County, education, the environment, agriculture, science and aboriginal affairs. He also contributes features, photographs and video.