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Innovative Ideas May Become Necessary to Manage Weeds

Problem weeds give Steve Kaltenheuser a headache. The difficult-to-kill eyesores like waterhemp spurred the Ames, Iowa, farmer to get creative this past summer. Kaltenheuser modified his son’s Miller Nitro 4365 sprayer into a bean rider to go through his 15-inch soybeans. His sprayer’s heavy-duty boom allowed him to mount seats from an old soybean rider. He then added umbrellas to protect the riders from the sun. This summer, the crew covered 1,400 acres that he didn’t think would be feasible to walk due to narrow rows.

The riders then sprayed the culprit, waterhemp, as they rode through the problem patches. Kaltenheuser had to innovate because of an early-season misstep with his herbicide program. In the spring, he incorporated Treflan followed by a second incorporated application of Authority First. 

“Both of those programs worked very well, and the beans stayed really clean,” he says. The issue came with his postemergence application. “I waited a little too long to hit them with Flexstar and Resource,” says Kaltenheuser. “I wanted to get them close to canopy, and that was a mistake.”

More management

A  few years ago, he switched to non-GMO soybeans. This enabled him to pick a high-yielding variety but still save seed costs. For Kaltenheuser, it’s about the economics. He grows the non-GMO variety because he’s able to reinvest the saved seed cost into his herbicide program. 

“When Roundup came out, it made everyone look like a professional,” says Kaltenheuser. “We’re losing that. There are more weeds out in cornfields than people realize. It’s going to become a lot more labor-intensive. To get ahead of it this year, I sprayed all the corn after brown silk with 2,4-D to try to prevent the waterhemp from going to seed.”

In the past, Kaltenheuser hadn’t had any problem controlling the weeds, but this year was the perfect mix of the wrong conditions in his area – like a lack of rain. 

Chemicals need some assistance

“I remember killing tall waterhemp easily a few years ago. Now waterhemp has to be killed when it’s really small,” says Kaltenheuser. 

Because of that, he relies on a herbicide’s residual benefits. Waterhemp has been causing plenty of people headaches. 

“Waterhemp has been really, really bad,” says Paul Kassel, Iowa State University Extension agronomist. “Glyphosate is no longer dependable. There’s also some confirmed resistance with Flexstar.”

The answer may be returning to practices from the past. “Farmers are going to have to double up on soil-applied products,” says Kassel.

He thinks farming is going back to how it looked in the 1970s and 1980s. The days of adjusting to programs based on the weeds in the field are gone. 

“We’re going to have to plan on what might be there,” says Kassel. 

Tips to prevent weeds 

  • Fit your planting date to your weed control program.  Shotgun approaches are no longer going to cut it, says Kassel. Herbicide programs will take more time and investment.
  • Make timely herbicide applications. 
  • Consider making extra trips. Double incorporation may be necessary for best results, says Kassel. 
  • Be innovative. “There’s been an interest in using residuals postemergence,” says Kassel. “I hear a lot of innovative approaches. Residual products don’t work unless it rains, so farmers have been incorporating it. I think people are adapting very well.”
  • Plan more.

Herbicides will still do 99% of the work, says Kassel. Yet, he predicts more intensive herbicide planning and management will be needed. 

Tillage is another tool Kassel believes farmers will turn to if needed. 

“I know of a few farmers who have pulled their cultivators out,” says Kaltenheuser. “I’m hoping I don’t have to do it again, but it’s a better option than walking the beans."

“The biggest thing I’m going to change next year is that I’m going to spray early on the postapplication,” says Kaltenheuser. “In the future, I’ll do anything I can to lower the seed bank. Back in the old days, before we had Roundup, it was a big concern if weeds went to seed. I’m going to have to look at weed control a lot more like I did in the past.” 

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