Researchers mapping phosphorus runoff hot spots in Lake Winnipeg

Darshani Kumaragamage, U of W professor, explains new research mapping phosphorus hotspots to protect Lake Winnipeg and improve soil health.

A Manitoba research team is mapping phosphorus runoff hot spots in the Red River Basin in a push to keep nutrients in farmers’ fields and out of waterways.

The team led by University of Winnipeg professor and soil scientist Darshani Kumaragamage is set to receive $218,000 over three years through the Lake Winnipeg Basin Program to bring the map to life.

Although the federal cash was announced in October, the team has already collected over 100 soil samples from Winnipeg to Emerson and Steinbach to Carman.

“We got tremendous support from the farmers, and we will be continuing this project over the next two years, so we will be reaching out to more,” Kumaragamage said Wednesday in an interview on Your Morning Winnipeg.

In some areas, researchers also installed snowmelt collectors to monitor spring runoff.

Along with the map, the team will also test several blended soil amendments, like gypsum and Epsom salts, to see if they improve phosphorus retention in farmers’ fields.

It’s hoped the map will give scientists a fuller and more accurate picture of phosphorus runoff in Lake Winnipeg during snowmelt to help find targeted solutions to phosphorus loss.

“What we expect from this research is to effectively reduce phosphorus losses from agricultural lands so that more phosphorus will be left on the soil where crops need it and less phosphorus will get into lakes where it can cause harm,” Kumaragamage said.

“It’s a win-win.”

Phosphorus has been a popular additive in Canadian agriculture for decades, supplying the soil with the primary nutrients that a crop requires to grow. However, when it seeps into waterways, it can cause a process called eutrophication, which leads to excessive growth of algae and aquatic plants.

“That degrades the water quality so that is the main issue,” Kumaragamage explained.

“When this algae dies and when the algae is getting decomposed, that depletes the oxygen level in the water, and that results in fish kills and that effects the ecosystem.”

In Lake Winnipeg’s case, phosphorus can run off through snowmelt, where in more tropical or temperate climates, it seeps in through erosion.

That means solutions designed for milder climates don’t suit the Prairies’ unique needs.

“Most of them are focused on reducing either erosion losses or rain-driven runoff losses. Very few are addressing the snowmelt runoff,” she said.

The map will focus on Manitoba’s portion of Lake Winnipeg’s massive drainage basin, while spans over one-million square kilometres.

Once completed, it will be put online for researchers, farmers and stakeholders to use.

The map is one of ten freshwater projects receiving funding through the Canada Water Agency aimed at protecting and restoring Lake Winnipeg.

- With files from CTV’s Rachel Lagacé