Uncovering myths about cover crops

By Sean Feagan, Local Journalism Initiative Reporter

Producers in Alberta are planting cover crops, despite claims to the contrary, according to new results of an ongoing survey by University of Manitoba researchers. 

Cover crops are plants grown on farmland not because they produce yields, but because they provide beneficial impacts, such as providing nutrients, erosion control or weed suppression. 

Each type is planted based on the specific problem or goal at hand, said doctoral researcher Callum Morrison.

“It’s like a toolbox,” said Morrison. “Each cover crop does some things very well, and other things, not so well.

“If you are trying to get nitrogen into your plants, you plant a legume. If erosion is your problem, you get something that might grow quickly and has a fibrous root system that holds things together. If it is compaction, you go for something like a radish that will get in there.”

The survey, which is ongoing and takes about five to 10 minutes to complete, examines what type of farmers are growing cover crops, how they are growing them and why they are growing them. It supports a larger study on cover crops by Morrison and his supervisor Yvonne Lawley examining the feasibility and impacts of planting cover crops at five field sites in Manitoba, Saskatchewan and Alberta.

“There’s no point in doing all this research if we don’t know anything about what Canadians are actually doing,” said Morrison. “There was no information out there about how cover crops are being used.”

The survey has dispelled a myth that Alberta producers do not use cover crops, said Morrison.

“Early adopters have been growing cover crops in the Canadian Prairies for several years,” he said. “In Alberta, it is basically niche, but I’ve had 55 respondents. Of course, that is not a vast majority, but it is happening.”

Respondents from across Canada grew 83,400 acres of cover crops in 2019, of which 15 per cent were grown in Alberta, according to Morrison.

Producers from across 30 counties and municipal districts in Alberta, including one respondent from Wheatland County, reported using cover crops. Cypress County in the province’s southeast had the greatest number with five, while several respondents were from counties around the Peace River in Alberta’a northeast, he said.

The study also disproved the myth that cover crops are only grown on organic farms, he said. “The majority of people growing cover crops are not organic,” said Morrison. “It’s not all organic.”

Of the respondents from Alberta, 22 planted “shoulder season” cover crops, meaning they were planted in the fall, while 45 grew full season cover crops. Shoulder season crops are more prevalent in Manitoba, where there is “more time to play with,” he said.

“There, you can actually get significant growth on any cover crop you, say, plant in the fall.”

While most farmers growing cover crops in Alberta do so every year, some plant them intermittently to fix problems or gaps as they happen, he said.

“Some people will only grow cover crops if it was too dry to sow their cash crop, they couldn’t get on the field at the right time or they got hail damage,” he said.

Planting cover crops seems to be gaining popularity in Alberta, with about 10 per cent of respondents saying they had only planted cover crops since last year, while 55 per cent started planting cover crops over the past two to five years. 

Oats, peas and clover were the most prominent cover crops planted in Alberta. The top five reported reasons for planting cover crops was building soil health, keeping plants growing in the soil, feeding soil biology, adding nitrogen and weed suppression.

So far, the research shows that planting cover crops “can be done,” but “won’t tell you if it’s the best thing to do for that farmer,” said Morrison, who added even a little bit of cover crop growth can significantly limit erosion.

“It doesn’t need to be some sort of jungle out there.”