Cover crops are one of today’s trendiest ag management tools. They are credited with a host of benefits: improving soil health and structure, warming spring soil, reducing wind and water erosion, adding nitrogen to soil, improving carbon capture and more. However, little research exists to date that shows whether they can be successful and productive as a shoulder season crop in challenging dryland prairie conditions. Farming Smarter is part of an ambitious four-year, multi-province study that aims to find key answers — and define next questions — about cover crops’ viability for Canadian dryland producers.

“I certainly see the value of cover crops.

The question is: how we are going to use them in a prairie context?” says University of Manitoba assistant professor Yvonne Lawley, the lead researcher on the study. “If we grow cover crops frequently in rotation, are they going to create the kind of transformative benefits to soil and to crops over time that we hear about in other areas? There’s a lot we don’t know at this point.”

There are five study sites across three prairie provinces conducting trials. Farming Smarter houses the Lethbridge site. Western Grains Research Foundation, Manitoba Pulse and Soybeans Growers, and Manitoba Wheat and Barley Growers Association fund the study.

At each site, research teams grow four different treatments: a four-year rotation with and without shoulder season cover crops, a two-year wheat-canola check rotation, and a perennial crop check rotation. The specific crops and cover crops at each site are representative of the region. In Lethbridge, the rotation includes wheat, canola, durum, and peas.

2021 will mark the fourth and final production year of the project. Final results will come by mid-2022. It’s too early for conclusive answers, but certain findings are already clear.

First: Mother Nature doesn’t always play along, especially in southern Alberta.

Drought in both 2018 and 2019 complicated cover crop planting and compromised results.

“One of the things we found is that implementation is a little more difficult than we might think sometimes,” says Mike Gretzinger, research co-ordinator with Farming Smarter. “If it hasn’t rained since the beginning of July and you harvest at the end of August, you can’t go in and seed it.”

Farming Smarter’s success rate at establishing and growing cover crops has been variable, Gretzinger says. Fall rye, winter peas and fall lentils have so far proven mostly successful. However, smaller-seeded cover crops like driller (tillage) radish and clover have provided greater challenge.

“It’s too early in the study to make predictions but I do think there will be some winners. There might also be some options that might not be useful in our growing conditions. I definitely expect regional differences,” says Gretzinger.

Of course, even failure in a research context is ultimately a win for producers.

“If producers try something new and have a fail one year, they sometimes say they’ll never try that technique or product again. That’s unfortunate since, maybe if they’d tried it in a different crop or under different conditions, it might have worked just fine. The benefit of Farming Smarter doing a trial over multiple years is we can try all different iterations: different treatments, different rotations and under different environmental conditions. That means we can give a little more nuance to the findings and, if it really doesn’t work, it’s not the grower finding that out on their own,” says Gretzinger.

So far, Lawley says the research is generating more agronomy questions than answers, especially at the Farming Smarter site.

“What we’re seeing right now is very little establishment and very little biomass production in southern Alberta. It’s important from a scientific point of view to document that. But if we are successful in getting more funding, we’re going to have to pivot our agronomic approach.”

Given southern Alberta’s challenging dryland conditions, next steps must include figuring out intercropping, she says.

Too, she’d like to look more closely at increased integration of animal agriculture, either directly through grazing or more diversely through annual forage production.

She also hopes to define a clear equation for cover crop’s impact on soil moisture. On the one hand, cover crops improve soil structure and water infiltration, allowing soil to retain more moisture. On the other hand, however, they use up soil moisture. “At what point do we cross the threshold of using too much water? I don’t know where that line will be,” she says. “We need to figure that out.”

The many unknowns don’t phase Lawley. In fact, she expected and welcomes them.

“This [project] is not like dialing in a nitrogen recommendation or choosing the right crop. It’s not about fine-tuning. What we’re doing and what farmers are doing is redesigning an entire cropping system. We’re not going to have the system figured out in four years, but we’re working towards understanding what the real questions are that will move this system forward.” 

“I certainly see the value of cover crops. The question is: how we are going to use them in a prairie context?”