Evaluating soybean varieties for suitability in organic production systems

Organic growers in Manitoba have limited options right now

At $25 a bushel, organic soybeans could be a highly lucrative crop for organic farmers.

But right now that market is out of reach for most due to the limited number of varieties suitable for organic production systems.

A student researcher at the University of Manitoba is hoping to change that. She is evaluating conventional non-GMO soybean varieties that could possibly grow in Manitoba’s shorter season.

Michelle Carkner is overseeing plot trials at the Ian N. Morrison research farm at Carman and working with farmers on five separate farms in southern Manitoba this summer.

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It’s the first study ever conducted in Western Canada to test the agronomic performance and determine relative maturity rates of mid- and longer-season varieties grown elsewhere in Canada.

In Ontario and Quebec, where soybeans have been grown much longer, farmers have many options among the later-maturing, non-GMO varieties developed for the growing conditions of those regions.

Manitoba organic soybean growers, on the other hand, are basically limited to growing mid-season non-GMO varieties such as OAC Prudence and OAC Erin.

“That doesn’t give them a lot of opportunity to check out different varieties and see how competitive they are with the weeds they have in their fields, and what kind of yields they can get and even maturity dates,” said Carkner during a field tour last week.

“I’m hoping that my research will really equip organic growers with a knowledge base of the different varieties and options they have, and basic agronomic tools if they want to grow organic soybeans.”

Carkner approached seed companies in Ontario, Quebec and North Dakota to see what they recommended among their earliest-maturing varieties. From their suggestions she selected 15 varieties for her research, including OAC Petrel, Toma, Tundra, Krios, Jari, Auriga, Savannah and SK0007 plus several numbered, unregistered varieties. She is also including OAC Prudence.

While it’s early to draw conclusions, some varieties are definitely doing better than others for weed suppression, she said July 22.

“I have noticed, especially with SK0007 and Jari and Savannah, that they were pretty vigorous early in the season,” she said, adding that data collected from the five participating farms at Elie, Swan Lake, Somerset, St. Pierre-Jolys and Woodmore will add to what this study will reveal about the varieties’ relative weed competitiveness.

Her trials also include experiments with higher seeding rates to see whether a denser stand combats weeds well enough to justify the cost of the extra seed.

The study will also generate data on podding heights, an important consideration in varietal selection because farmers don’t necessarily want to have to buy special harvesting equipment for soybeans.

Whether some of these longer-season varieties even reach maturity in cooler Manitoba is, of course, a big question.

Savannah, is a case in point.

“We’ll have to see if it even matures,” she said.

However, in mid-July Savannah is looking taller and leafier than the other varieties and therefore may be a good green manure crop to recommend for organic growers, she adds.

SK0007 and one unregistered variety — SVX14T0053 — are also doing a good job with weed suppression.

Researchers also want to find out what yields will be when grown organically. Most of these varieties yield anywhere from 40 to 50 bushels an acre, but that’s been under conventional, non-organic variety trials, Carkner said.

She has set aside a block in her plots at Carman to keep weed free and collect comparative data on yields.

Carkner’s research is jointly funded by Steinbach-based Growers International Organic Sales Inc. and the Natural Sciences and Engineering Research Council of Canada (NSERC).

University of Manitoba plant science professor, Martin Entz and Carkner’s research adviser said this work is going to generate a lot of practical information for organic farmers.

Grain companies want organic soybeans and are urging farmers to grow them, Entz said. “The markets are very strong.

“But variety selection is especially important in soybean because we have a relatively short season and we have to be very careful with the varieties that we select based on their maturity.

“Up to now, nobody has looked at how the candidate varieties perform on organic farms,” he said.

About the author


Lorraine Stevenson

Lorraine Stevenson is a reporter and photographer for the Manitoba Co-operator with 25 years experience writing news and features. She was previously a reporter with the Farmers Independent Weekly and has also written for community newspapers in Winnipeg and Manitoba's Interlake.



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