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Light frost but little to no soybean damage

Good growing conditions allowed the crop to escape damage, but it underlines the importance of the right variety

Temperatures hovered at or just below freezing across much of the province both Sept. 13 or 14, but apart from a few clipped leaves, there was little damage to soybeans.

Soybean producers are always worried about an early frost with the long-season heat-loving crop, but this time the crop had advanced enough to prevent damage, Dennis Lange, Manitoba Agriculture’s pulse crop specialist said in an interview Sept. 15.

“It’s a bit of a non-issue for the most part, but it shows that we can still get a frost at this time of year,” he said while traveling to soybean plots at Rosebank in south-central Manitoba. “Even some of our long season varieties are starting to mature by about September 14 or 15. But you have to remember though we’ve had a fairly warm summer and things have moved along quickly. But if you get into a year where it’s a little cooler some of these varieties might hang on a little bit longer (and be more susceptible to early frost).”

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That’s why Lange stresses farmers need to plant soybeans with a maturity suitable for their growing region.

“We’ve had some calls about black pods but probably it was black before because it’s more of a sunburning affect,” Lange said.

The majority of Manitoba soybeans are in the R7 to R8 stage. although there are pockets at R6.5. he said.

R8 is when soybeans are fully mature. At R8 soybeans are leafless, 95 per cent of the pods are brown and seeds rattle when pods are shaken. Soybeans frozen at R8 suffer no yield loss but quality can be damaged.

Yield losses of zero to five per cent occur when soybeans are frozen in the R7 stage.

At R7 the green colour is gone in seeds found in pods on the top four nodes of the plant.

Yield losses of five to 15 per cent occur when frost hits at the R6.5 stage. That’s when pods are turning yellow and seed moisture content is 65 to 70 per cent.

“There was a touch of frost around that Hamiota area… and even there it was just down to perhaps zero or just below, and in the Snowflake area there might’ve been a touch of frost but I would say there are not a lot of soybeans in that area. So overall things are pretty good.”

Lange said he saw farmers harvesting soybeans between Morris and Rosebank Sept. 15. Some farmers were harvesting soybeans in the Altona area earlier this week, he added.


About the author


Allan Dawson

Allan Dawson is a reporter with the Manitoba Co-operator based near Miami, Man. Covering agriculture since 1980, Dawson has spent most of his career with the Co-operator except for several years with Farmers’ Independent Weekly and before that a Morden-Winkler area radio station.



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