News

Herbicide carryover concerns this spring

Dry conditions in 2023 could lead to increased risk of herbicide carryover in soybeans this spring.

Aaron Hager, weed scientist at the University of Illinois, says herbicide applications made to abnormally dry soil last season could still lead to springtime issues even with near normal winter precipitation…

“If you’re applying a material to a very, very dry soil, you can actually have a lot of adsorption that takes place almost immediately.”  He says, “Those products that are adsorbed, sometimes they will get more strongly adsorbed overtime, which means it can take more moisture to actually release those from the soil colloids. When they’re bound; they’re not available for degradation.”

Illinois has seen below average precipitation trends continue in recent months.  Hager tells Brownfield this year is similar to last spring…

“The rainfall patterns that we got following the application may have been a little bit more favorable than what we saw in ‘22,” he says, “but still we think there is that potential again, especially in areas that were dry during the post application time in ‘23.”

He says the timing of soybean planting is another factor in carryover risk…

“We have rotational intervals on many herbicides.”  He says, “We’re simply not going to be able to satisfy those rotational intervals if we continue to try to plant soybeans earlier and earlier in the spring.”

Hager doesn’t expect widespread problems this spring but does say it will likely be more of a problem for producers who plant soybeans earlier.