By Laura Barrera
Gabe Brown can sympathize with dryland no-tillers struggling to control noxious weeds, particularly those using an undercutter to battle herbicide-resistant weeds.
“I can understand why those producers are concerned about perennial weeds in no-till, but realize that what they are more or less doing with an undercutter is putting a Band-Aid on one foot and then shooting themselves in the other,” the Bismarck, N.D., no-tiller says. “They are moving those restrictive layers to right below where that undercutter runs.
“What we’re finding is that as you advance soil health and get the biology and micronutrients cycling, weed issues tend to go dramatically down and they are not as much of a problem.”
Brown says he averages 16 inches of precipitation annually between rainfall and snow on his farm in southern North Dakota and has been able to prove that cover crops can work in low-moisture environments to help with weed suppression; however, he says dryland farmers likely need to add perennials into their cropping rotation and graze cattle rather than intensively raise grain crops.
“If nothing else, instead of a cash crop, do what I’m doing by adding years of double-crop cover crops,” Brown says. “I will seed that rye-vetch combination in the fall, graze it in the spring and then seed a diverse polyculture cover crop and graze it.
“We’re converting those cover crops into dollars by grazing. There are times we can profit well over $300 an acre just by doing that. I ask corn producers how many made that on their corn and nobody can come close. What we’re doing is cycling carbon and that’s what feeding biology is all about.
“I really think there’s going to be a wave of producers in these drier environments that will be going to that production model where you have a year of cash crops followed by a year of cover crops that are grazed. That’s how we’re going to build soil health in these drier environments.”
Kansas State University soil scientist Augustine Obour agrees that if a no-tiller wants to try using cover crops to suppress weeds, he should plan to graze it or sell it for feed. He says cover crops can reduce soil water content, so capitalizing on the cover crop instead of just terminating it is one way to maintain profit in case the subsequent cash crop takes a yield hit.
Weed Control Options
Washington State University agronomist Bill Schillinger says that in his part of the country, no-tillers may be considering undercutting to control weeds, but he believes the vast majority of them don’t want to. For those growers, he recommends they contact their weed scientists and see if there are better tankmixes they might consider trying.
“If their passion is in no-till and they just really don’t want to undercut, then stick with it,” he says. “The key to managing those weeds would be mixing and matching your herbicides. Do it more effectively than you have done.”
Growers could also consider using a tool like the WeedSeeker Spot Spray system. Schillinger has seen growers use it and says they can cut up to 90% of herbicide use while still terminating weeds effectively.
But his concern with relying just on herbicides is that it may not be cost effective. Obour agrees that a system with both undercutting and herbicide applications can be a more cost-efficient program than relying on herbicides alone.
A custom herbicide application is currently around $12 per acre in his area, he says. If a grower needed to make four herbicide applications during summer fallow, Obour says he could probably save on a pass by undercutting first and following with two herbicide applications to control remaining weed flushes.
He adds that those flushes would also be easier to control with herbicides since they’ll be smaller, whereas that might not be the case if using herbicides alone.
In the end, Schillinger says, it’s up to every farmer to determine what is best for his system and bottom line.