Laurent “Woody” Van Arkel likes to push the boundaries of conventional thinking and strives to understand more about soil and crop interactions.

Van Arkel, who farms near Dresden, has finished a five-year, on-farm research project as a participant in Agriculture and Agri-Food Canada’s (AAFC) Living Lab Ontario initiative in which he integrated perennial cover crops into a row-cropping system. For Eric Page, a researcher with AAFC’s Harrow Research Station, the notion that Van Arkel has used a perennial cover crop and twin-row wheat and has come close to standard yields in wheat and soybeans means there’s more to be learned about corn.

Why it matters: Achieving conventional corn yields using perennial cover crops in the cropping system is still elusive, but on-farm research trials are trying to help understand how to close the yield gap.

“He narrowed the yield gap on his wheat and soybeans quite effectively while we were there working with him,” says Page. “Going forward, what are the questions that need to be addressed in the cropping system? And I would say corn is the system in that rotation that still needs the most attention.”

With Van Arkel’s systems approach, Page emphasizes that corn and soybeans are summer crops. Yet in dealing with winter wheat and searching for balance within the rotation, there’s desire for a leguminous cover crop for soil protection and nitrogen-fixing. That has to be weighed against competition with the crop in question.

The Research

Van Arkel’s goal was to keep a living cover crop year-round while reducing herbicides, improving nutrient cycling in the soil and controlling traffic. He hoped to improve production while protecting what goes on below the soil surface.

He started formulating the basis for this research 10 years ago and says he could happily continue it for another five.

“Keeping cereal grains as part of the crop rotation and trying to integrate perennial cover crops is not straightforward,” says Van Arkel. “I tried seeding winter wheat in wide twin rows similar to corn and soybeans, with the goal of evaluating different varieties of wheat to see how they react in wide rows. That’s where I’m working on the twin-row, wide-row wheat, so I can put it into that perennial system, so I’m growing my crops on the same strip every year.”

The perennial cover crop is perpetual, with Dutch white clover and subterranean clover, which he adds is not a true perennial but a variety that will flower in May. At that point, it goes to seed, replants itself in July-August and by the end of September provides a mat of clover.

He says sourcing seed is the toughest part of using subterranean clover as a perennial cover crop. Since clovers are not winter hardy, Van Arkel has been on a two-year quest to determine the specific species and how to maintain a steady source. Some of it originated in Australia, some in Washington State and some in Chile.

The other challenge is keeping the low-growth clover from competing with primary crops.

“My first couple of attempts, I was trying to terminate six inches of cropping strip but that’s not enough," Van Arkel says. "I’m out to 14 inches and that allows the crop to get established, get up, and then the clover will creep back in. This year was the first year I used herbicide between the rows. The first three years of the project, the sole herbicide or weed-control measure between rows was the perennial, and the only thing I’m struggling with is Canada thistle.”

Proof in Performance

Yields in the two cropping plans are close to conventional numbers, at roughly 80% of conventionally produced corn. Soybean yields were nearly 90% in some parts of his plots.

With winter wheat yields, there was no statistical difference, said Van Arkel, and in terms of soil health, the chase is on for “the full tank” theory.

“There was a comment by one of the researchers who said this may take two or three or four years for the tank – for the soil biology to get to a level or a capacity that it’s no longer taking in – that it’s full," Van Arkel says. "Hopefully, it’d be nice to see if I can reduce some of my nitrogen inputs in the system, but that’s yet to be determined."

Seasonality Considerations

Achieving greater corn yields may be addressed by accounting for seasonality, says Page.

“You have a difference in the seasonality of the crops,” Page says. “There are selection options in the system for the type of covers that you put in and the seasonality of the cover is also going to dictate how successful you are. With corn and soybeans, the seasonality is very defined. Winter wheat’s a little different, so you need to stagger when that cover is going to be big and lush versus when you want your crop to be producing its yield.”

What’s Old is New Again

Page believes the perennial crop concept dates back to discussions about subterranean clovers acting as “living mulches” in the 1980s and ‘90s. It was also mentioned in scientific literature 50-60 years ago.

Now it’s a matter of deploying those older concepts using tools that may not have existed to the same depth or complexity as they do today. Newer strip-till tools can help.

“It’s not necessarily a new tool but then not everybody has one,” Page says. “What Woody’s using in his system is managing with a living mulch, banding herbicides, strip tillage and mechanical weed management. When we start talking about innovative cropping systems or inter-cropping, they’re just different tools. We can make use of a basket of technologies that can help us now with some of the challenges with these innovative systems that we thought were good 50 or 60 years ago.”

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