The Inventions of Oil is a CBC Edmonton series about oil and gas innovations hidden in our everyday lives.

After harvest and before the snowfall, John Guelly injects fertilizer into his farm fields near Westlock.

He uses anhydrous ammonia, made from natural gas extracted from deep underneath fields just like his. The fertilizer contains nitrogen, an important ingredient that help farmers replenish soil nutrients.

"It's the gas that grows the crop," Guelly said, who grows canola, malt barley and wheat. "There's a lot of other fertilizers that we require, but nitrogen is by far the most highly used and the most required to grow a proper plant."

Nitrogen is one of three major macro-nutrients — along with phosphorus and potassium — necessary for plant growth.

Super-charged fertilizer

If you buy a container of plant food or a bag of Miracle-Gro for the tomatoes in your garden, chances are the nitrogen was made from natural gas. Ammonia or urea (a solid made from ammonia) are the richest sources of fertilizing nitrogen available.

Synthetic fertilizers are essentially a supercharged version of organic fertilizers, like compost and manure. Hog manure has about one per cent nitrogen, while urea contains closer to 46 per cent.

Guelly is a third-generation farmer who works land not far from where his grandfather first homesteaded in Alberta. He doesn't remember a time when synthetic fertilizers weren't used on the farm. His father, Elmer Guelly, said it started in 1968, immediately after he took over the family business.

John Guelly is a third-generation farmer in Westlock, Alta. He explains how natural gas, extracted by companies from under his own field, ends up fuelling his crop. 1:32

Elmer Guelly remembers how unimpressed his own father was when he came back once for a visit. "I'm sitting here with a granary full of fertilizer, more than he would have used in 10 years, probably," he said. "He couldn't understand why I would spend that much money on fertilizer to grow a crop."

But that fertilizer increased his yield by 40 per cent in the first year, he said.

These days, John Guelly said, fertilizer can double the potential yield.

An explosive idea for agriculture

In 1909, Nobel prize-winning chemist Fritz Haber developed the Haber process to turn atmospheric nitrogen into ammonia.

Nitrogen in the air is a stable compound but Haber discovered it could be broken apart when combined with fossil fuels under high-pressure. That created ammonium nitrate, a chemical compound of nitrogen, hydrogen and oxygen that can be used to feed crops.

Elmer Guelly started using synthetic fertilizer in 1968, the same year the Nutrien plant opened in Redwater. (Ariel Fournier/CBC)

By 1913, the Haber process was adopted for commercial agricultural use in Germany. When the First World War broke out, the country stumbled upon another use — explosives.

"The process was not developed to make explosives," said energy historian Vaclav Smil. "But you need nitrates for explosives, so it came in handy. But the process was explicitly started, and then developed, to provide nitrogen to feed more humanity."

The discovery wasn't adopted on a global-scale until after the war, when methods were found to extract mass quantities of natural gas. Today, natural gas is the most reliable source for fertilizer ammonia, though some countries continue to use coal.

The use of fertilizer has dramatically increased crops yields. Had average yields from 1900 remained unchanged, by the turn of the next century, in order to support the population, food crops would have taken up nearly half of all land on ice-free continents, Smil wrote in a research paper.

Instead, about 15 per cent of the Earth's total land mass is needed to grow food.

"This was perhaps the most important invention in human history, in the sense that you have something like three or four billion people alive today who wouldn't be otherwise," said Smil, a professor emeritus at the University of Manitoba.

In Alberta, the first significant discovery of natural gas was in Turner Valley in 1914. But development of the industry was delayed by the Depression and two world wars. Soon after the Second World War, production of natural gas quadrupled.

Canada is the fifth-largest supplier of natural gas in the world, and most of that comes from Alberta. Less than 10 per cent of extracted natural gas is converted into ammonia for fertilizer; Canada is the world's sixth-largest exporter of that ammonia.

A growing market

Around the world, the use of nitrogen fertilizer grows steadily each year. Within Canada, its use is about 50 per cent higher than it was a decade ago.

The ammonia-producing Nutrien fertilizer plant in Redwater is one of the largest fertilizer facilities on the continent, stretching 372 hectares along the North Saskatchewan River.

Synthetic fertilizers have changed life for farmers.

The Nutrien plant in Redwater is the largest fertilizer plant in North America. (Ariel Fournier/CBC)

"Today it's very scientific," said Smil. "It used to be kind of slap-dash but now the farmer has his field analyzed."

Analysis might show the field has high levels of potassium, which means the farmer can adjust the fertilizer to apply only nitrogen and phosphorus, he said.

Phosphates and potash (a source of potassium) can be mined from the ground.

St. Albert horticulturalist Jim Hole, who has worked in field crop production, said synthetic fertilizer has helped make agricultural soil healthier, bringing it closer to the state it was in before intensive farming took its toll.

"They don't till the fields anymore because that wrecks the organic mass," he said. "So what's happening is, there is a net gain of organic matters in the soil. And that's happening in conjunction with the synthetic fertilizer."

That means less labour, and farmers don't have to feed the soil as frequently, which in the end saves money, said Hole.

"It's a major, major improvement."