Though an increasing number of farmers swear by the multiple advantages of cover crops, science lags in measuring how significant those advantages are exactly. Farming Smarter and the universities of Manitoba and Saskatchewan want to fill that gap. Together, they are one year into a five-year collaboration to determine the economic, soil health, environmental and crop productivity impacts of growing post-season cover crops.

“Farmers use cover crops because they see the benefits. Does it make those benefits less real because a scientist hasn’t measured them? No,” says the study’s lead researcher, University of Manitoba plant scientist Dr. Yvonne Lawley.

Still, she says there is real benefit to rigorous scientific assessment of cover crops.

“There’s a lot of excitement but not a lot of data on how best to grow cover crops in various regions. This study isn’t going to answer all of those agronomic questions, but hopefully it will lay the groundwork for the big questions we have about cover crops’ impact.”

The five-year, small-plot study has four sites: Farming Smarter’s research fields in Lethbridge, the South East Research Farm in Redvers, Sask.; the University of Saskatchewan’s Research Farm in Saskatoon; and the University of Manitoba’s Research Farm in Carman, Man.

At each site, researchers will grow a four-year crop rotation suited to each growing region.

Each location will grow each crop in the rotation every year, both on its own and in conjunction with a shoulder season cover crop, for a total of eight small plots. The specific crops grown at all locations have been selected to suit each site, but will all include canola, wheat, a pulse, and a grass each year. Cover crops are paired to complement each crop type and include rye, clover, radish or a legume like peas.

“What we’re doing is comparing each rotation on its own and then comparing those to the same crops grown with cover crops,” says Lawley. “In some ways, it’s a simple design: we’re just comparing with and without cover crops. But, it gets complicated because every year we’re growing every crop type, and we have different cover crops paired with each crop type.”

The research team will also grow two checks at each site: the tight (exclusively canola/wheat) rotation used by farmers to maximize profit, and a soil health maximizing, perennial grass/legume stand.

To round out the study with real-world economics, the researchers will work with farmer Adam Gurr, who established a field scale strip trial on his farm near Brandon. Though his trial will not have as many treatments as on the research farms, Lawley say his results will allow the team to compare budgets to a working farm.

The researchers hope to measure a whole array of cover crop impacts from crop yield to biomass productivity and from greenhouse gas emissions to soil health indicators (including microbial properties, enzymes, and nutrient cycling). As importantly, the team will also analyze the economics of these many impacts.

“There are a lot of collaborators on the study, which means we can look at this from a lot of angles. We’re going to do some pretty cool stuff with these trials, especially as the treatments accumulate,” says Lawley.

Over the years, various scientists conducted studies on long-term crop rotation, green manure crops in organic systems, and cover crops that replace fallow. What’s new about this study, says Lawley, is that the team will look at the impacts of shoulder season cover crops grown within a regular crop rotation.

“There’s a real paradigm shift for the types of cover crops and the timing of those crops,” she says. “There are some really simple reasons why cover crops make sense. Hopefully in this study we will put numbers to the system wide benefits.”

The prairie-wide project was originally developed in hopes of gaining funding from the Integrated Crop Agronomy Cluster overseen by Western Grains Research Foundation (WGRF).

When it was not ultimately selected for inclusion in the Cluster, the WGRF, Manitoba Pulse & Soybean Growers, and Manitoba Wheat and Barley Growers Association decided to fund it instead.

“It’s very exciting to see this work funded by producer groups,” says Lawley.

Findings from the study could help fine-tune producers’ management decisions, should encourage additional uptake of cover cropping, and may provide the background necessary for additional environmental goods and service payments.

After all, she says “What’s the point of doing this work if it’s irrelevant to farmers and just going to sit on a shelf?