From scattered sunlight to dozy bees, smoky days challenge Canada's food growers

The smoky air that has become an all-too-common feature of Canadian summers poses yet another challenge for agricultural producers already contending with chronic drought in some areas and excess moisture in others.

A thick haze blanketed much of the Prairies and Central Canada on Monday as wildfires burned in northern Saskatchewan, Manitoba and Ontario.

Environment Canada issued air quality warnings advising people to stay indoors — not an option for those growing the food Canadians rely on.

As for how the smoke affects the crops themselves — it's complicated, said Ashley Ammeter, whole farm specialist at the Manitoba Crop Alliance.

"One of the big challenges we have is that although some of these wildfire events are becoming more common, they're still relatively unpredictable and that also makes it hard to properly study these effects," she said.

The haze can reflect and interfere with sunlight, which could disrupt photosynthesis. How that affects yields depends on the type of crop — soybeans would likely fare better than corn — and the timing of the smoky days, Ammeter said.

Ozone produced when sunlight is exposed to pollutants in the smoke can also damage plant tissues and leaves, potentially reducing yields.

On the flip side, smoke could scatter sunlight in such a way that it can better penetrate the canopy of a tall crop like corn. It can also reduce temperatures — a benefit or a drawback, depending on whether recent weather has been hot or cool.

Either way, there's not a lot a grower can do.