Relay cropping adzuki beans into winter wheat

A Woodville-area farmer aims to benefit from multiple crops in one field

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A volunteer crop from the previous year growing between the rows of the present year’s crop represents a nuisance to most farmers, but not to Dustin Mulock.

Instead, a patch of volunteer adzuki beans growing — as he described it to the recent annual general meeting of the Ontario Bean Growers (OBG) — “a stone’s throw away from a soybean field that was suffering from drought stress” provided Mulock with inspiration to further his exploration of no-till agriculture.

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Why it matters: Edible beans – with greater management requirements than soybeans — haven’t been a regular area for cover crop or relay crop experimentation, which is what makes Mulock’s work unique.

Mulock, Woodville-area farmer chronicled a 31-year no-till journey begun by his father.

“We are what we consider, now, to be a never-till farm. We’ve been that way since 2015,” he said, adding he’s driven to continue the soil-health journey for the sake of the farm’s next generation.

“Instead of destroying the biology of the soil with tillage, we wanted the biology and the roots of the plant to do the work (conventionally done through tillage) for us.”

Early experimentation at the farm included using what Mulock referred to “cover crop bio strips”, using a “no-till strip tiller.” Bio-strips include a strip of cover crop that degrades quicker, where the next crop is planted and then a denser cover crop in between. When seeding is undertaken, he calls it “driving on the green and planting in between.”

Planting in these conditions sometimes requires equipment modifications. Mulock showed a picture of a 22-inch disc that has been added to a planter to help create more down pressure to plant through cover crop trash. They also added down pressure air bags to their corn planter.

The modification that has been most revolutionary on the farm in recent years is the creation of a twin-row planter that’s typically set at 22 inches of space between two closely spaced rows (first 7.5 inches, later 6.25 inches) of crop.

Relay planted adzuki beans with wheat shown at Dustin Mulock’s farm.
photo: Dustin Mulock

This 22 inches gives the plants “breathability” by allowing for ample air flow up and down the row. This is helpful in preventing infestations that can often develop in humid, warm environments. But more importantly, this modification also allows for relay cropping — a strategy Mulock has taken to with enthusiasm ever since he saw those volunteer adzuki beans back in 2012.

Seeing a crop thrive in the shade and protection of another crop flicked on a lightbulb. Why not seed a spring-planted crop into the inter-row spaces of an already-standing fall-planted crop, thereby ensuring there are roots in the ground all year around?

He first followed a crop of soft white wheat with soybeans planted into the standing wheat. He has since moved to soft red wheat and adzuki beans.

Mulock said relay cropping is a step toward recreating the symbiotic relationships evident in the diversity of nature as opposed to the monoculture of conventional agriculture.

“We want those two (crops) to talk and share together through the mycorrhizal system (of fungi) on the plant roots.”

One challenge has been ensuring the wheat is far enough advanced in the spring so the beans can be planted into a moist soil. If the wheat hasn’t reached third tiller by the time the snow flies, it can spell trouble. In fall 2019, he explained, with an aim to getting the wheat planted in a timely manner, they’ll try expanding their relay strategy by planting the winter wheat into a standing crop of soybeans.

Between May 9-15 is the Mulocks’ normal planting window for adzukis.

“If there’s one crop that lends itself to this situation, it’s the adzuki bean,” he said. As long as there’s water early on, if a drought comes later, it will still take off when the rains return.

His herbicide program must consider the needs of both crops. He’s on the lookout for a hooded sprayer so he can get the chemicals only on one crop and not both. Either way, there are a lot of variables to consider and he is finding it a steep learning curve.

You also have to find a way to protect the growing beans from the combine header during wheat harvest. They tried a few things — some which could have been quite expensive if they decided to pursue them fully — but eventually settled on “a $140 sheet of hard plastic cut into 18-inch strips. We took a torch to it to give it a bend and bolted it to the front of the header.”

The plastic addition gently pushes the beans down as the wheat is cut.

Dustin Mulock modified his combine header to gently push down the adzuki beans while harvesting wheat.
photo: Dustin Mulock

He said it’s critical that the wheat is cut short because that eliminates the shading for the beans and sends a message that the competition for light is gone.

They also orient their wheat east-west so the sunlight can penetrate to the beans as they’re growing in between the wheat.

If you’re using soybeans, use longer-day varieties or the beans will jump straight to maturity as soon as the wheat is gone and an opportunity will be lost for further pod filling. The adzukis, though, “are very good at continuing to push” after the competition is gone.

The Mulocks manufactured extensions to the axle on their round baler so the wheels would not pass over the beans when baling the wheat straw.

In the summer of 2019, he explained, with an aim to expand their relay strategy, they’ll try planting their 15-species cover crop mix into the wheat stubble between the rows of a standing crop of beans.

About the author


Stew Slater

Stew Slater operates a small dairy farm on 150 acres near St. Marys, Ont., and has been writing about rural and agricultural issues since 1999.



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