Soybean School: Making the case for planting soybeans before canola


Drier weather over the last few years has taken some of the wind out of soybeans’  sails in Western Canada, but there’s a case to be made that fundamental climate trends on the Prairies still support good soybeans yields in the longer term.

Especially if growers are on the ball with planting when the soil is ready — possibly even planting ahead of canola — says Bryce Rampton, product development agronomist for soybeans with Syngenta, based at Morden, Man.

“I think when you look at the long run and the fundamentals, I think it sets up really well, with frost-free period, overall rainfall, and periodic rainfall. All those factors line up really nice to be able to maintain and achieve a really good yield of soybeans, but that’s the difference between weather and climate,” he says, referring to the drier weather conditions in much of Western Canada’s soybean area over the last two or three years.

While western Canadian growers usually plant soybeans after wheat and canola acres are complete, Rampton makes the case in this Soybean School episode that soybeans should be planted ahead of canola, especially in a delayed spring.

It’s all about having the plants begin flowering as early as possible to benefit from those Prairie rainstorms that tend to roll through in early summer.

As Rampton explains, you want as many heat units accumulated before the days start getting shorter in the third week of June, which is when soybeans shift into reproductive mode. The more plant growth and node development before that, the better — which is why he says a May 15 planting date can have significantly different results than a crop planted on May 30.

“To maximize the benefit from that moisture in late June, early July, I think it really pays to get the soybeans ahead of the canola. I think the only thing that will be sad will be the flea beetles, with some of the challenges we’ve been having with early planted canola,” says Rampton.

Planting as soon as the soil is ready still means waiting for the ground to be warm enough for that critical first 48 hours in the ground, as cold temperatures will cause imbibitional chilling and set the crop back from the beginning.

“When you get that 5 or 6 degrees C, or less, it really disrupts enzyme activity within the seedling. We can see corkscrewing and stressed emergence from that,” he notes.

If the weather doesn’t cooperate and planting is delayed until the end of May, Rampton suggests increasing your target plant population by 10 percent to compensate for the lower number of potential nodes per plant.

Bryce Rampton discusses Western Canada’s climate and soybean planting date strategies in this latest Soybean School episode:

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