Weed seed destroyer, other control methods shown

Weed control in agricultural fields is an annual challenge, especially with more weeds becoming resistant to herbicides. Fortunately, growers have a wide range of weed control options, including creative ways that may not have been used in the past.

At this year’s Farm Progress Show, Iowa State University Extension and Outreach will showcase one of the most innovative and practical methods of weed control: a weed seed destroyer.

Mounted on a combine harvester, the weed seed destroyer does what its name suggests. It pulverizes and destroys the seeds so they cannot germinate.

The weed seed destroyer (Redekop) will be attached to the back of a John Deere S680 combine harvester and can be seen outside the ISU outreach and outreach tent.

Although the machine is not in operation during the show, visitors can see it in operation on a computer screen and ask questions of weed experts.

“We want to give the public a chance to see and ask questions about this innovative form of weed control technology,” says Prashant Jha, ISU professor and extension weed specialist. “Farmers in central Iowa and Harrison County are already using this technology, and we expect more to do so in the years to come.”

Alternative methods

Other weed control methods will also be shown, including videos of straw sheathing, a method that guides harvested straw in narrow bands as it flows down the back of the combine during harvest, which reduces the spread of weed seeds by more than 95% across fields and contains weed seeds in smaller spaces.

The harvester or combine harvester is modified with a deflector that separates the chaff (containing the majority of weed seeds) from the straw. The straw is directed into narrow central bands using a chute at the rear of the combine.

Weed seeds in the bale are prone to rotting, and burying small-seeded weed species such as water hemp in the bale will potentially result in reduced emergence the following growing season. High herbicide application rates or shielded sprayers can be used to selectively control emerged weeds in these narrow strips of the field.

The Weed Control exhibit will also allow visitors to test their knowledge of weed specimens found in the Midwest. Sixteen different species will be available for visitors to identify.

Visitors will also have the chance to learn about water hemp and how to suppress it using grain rye as a cover crop.

Photos and sample trays will show the results of using no rye, rye finished 4 to 6 inches high, and rye finished near heading.

“We are going to show the potential of biomass [cover crops] to suppress weeds like water hemp, and how the results vary depending on the height of the cover crop,” says Jha.

Rye helps suppress weeds

Cereal rye has the best potential for weed suppression because it accumulates more biomass than other cover crop species. A study done for the Farm Progress Show shows a gradual decrease in water hemp as a function of rye density.

Field studies indicate that a grain rye biomass of 4,500 to 5,000 pounds per acre at the end can significantly suppress water hemp emergence in soybeans and reduce hemp height and density. water at the time of post-emergent herbicide exposure.

Additionally, growers can view a map of where herbicide resistance has been documented in Iowa based on the recent survey and ask Jha and other experts about their own weed experience. herbicide resistant.

Jha will be joined at the show by ISU Extension and Outreach field agronomists Angie Rieck-Hintz, Meaghan Anderson, Gentry Sorenson and Mike Witt, and several graduate weed science students.

Jha is ISO Professor and ISU Extension Weed Specialist.

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