Putting beans and soybeans in the same rotation is dangerous, says Dennis Lange of Manitoba Agriculture.
Even a tiny amount of soybeans in an edible bean sample can make the beans undeliverable.
“Even having half a percent volunteering in your pinto bean field, you could get rejected at the elevator,” Lange told the recent Manitoba Special Crops Symposium.
That’s because soybeans are considered a food allergen in the edible bean business. There is almost no tolerance for them.
Soybeans and edible beans have been butting heads in Manitoba’s Red River Valley for years, with many traditional edible bean growers trying soybeans or putting soybeans into their rotations.
Edibles have been a significant crop for decades, but soybeans are a phenomenon of the past decade, going from near-zero acres to probably more than one million this year.
Edibles will probably have less than 100,000 acres in Manitoba this spring.
Lange said soybeans tend to have a .5 to three percent volunteer rate if they are grown on a field two years previously. They can’t always be cleaned out by a colour sorter, especially if they have matured by the time they are harvested.
Lange said he would even be hesitant to put edibles on a field used for soybean production three years previously. It’s best to dedicate fields to one or the other and stick with that, he added.
“If you have a field that’s suitable for edible beans and you have fields on your farm that are suitable for soybeans, neither the two shall mix.”
Edibles do best on well-drained, sandy soil, so those fields make most sense for that crop. Soybeans can handle wetter soil better, so those types of fields work well for that crop.
Lange encouraged farmers to keep careful track of their fields’ production history because it can be hard to keep track of what has been grown on each field, especially if farmers have had to reseed acres because of weather problems.
“Unfortunately, sometimes growers forget what they had two years ago,” said Lange.