Grinding down glyphosate-resistant weeds with cereal rye and planting green

(Kara Oosterhuis/RealAgriculture)

There’s no silver bullet when it comes to managing weeds, and managing herbicide resistant populations is even tougher. One of the best ways to get ahead of weeds is crop competition. Jim Stute, independent research agronomist, has been evaluating the role of cereal rye as a weed suppressing crop to surprising results.

Recorded at the National No-Till Conference at St. Louis, Missouri, in this video RealAgriculture’s Kara Oosterhuis gets the goods on how using rye in rotation ahead of soybeans can get the jump on not just early weed control, but later emerging weeds as well.

Stute’s work has looked at cereal rye’s role in suppressing the big baddies: waterhemp, giant ragweed, and mare’s tail. This specific project combines not only the use of fall-seeded cereal rye, but also two different seeding rates and termination timing of the rye.

The project is designed to suss out if it’s just biomass driving the weed suppression, or if it’s the rye itself that’s responsible.

“If we terminate the rye late, what we call planting green, so the beans are planted, they’re already up, we wait until the rye pollinates, we’re seeing across species 90 to 95 per cent suppression, which is huge from a weed competition standpoint. The good news is even if we terminate right at planting, we’re seeing a 50 per cent reduction in populations and a slight yield bump of two to three per cent in soybeans. So that’s huge also, and we’re getting the weed suppression benefit. And if we can reduce the number of post emergence applications, also resistance management. It’s huge,” Stute says. There was, however, a yield reduction in beans with late termination. (Story continues below video)

This impressive weed suppression has impacts throughout the growing season and impacts other spray decisions as well, Stute says.

“What that does is it shifts the emergence of those weed populations to later in the season, but when we can still apply the herbicide. That means we can maybe get away with one post emergence application,” he says. The decreased overall weed population is a cost savings for the farmer, but also another step towards resistance management because it saves another pass of selection pressure.

Stute works with a group of cooperator farmers on this research project, a set-up, he says, that’s invaluable to getting good data. Not only does multiple sites speed up the data collection and integrity of the numbers statistically, but trialing across many farms means the research captures more weed populations, types, and soil differences.

He adds that working with farmers means that the questions being asked or evaluated are real-world applicable right from the start.

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