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Determining ‘off-target dicamba’ yield loss is a challenge

In addition to the normal challenges associated with harvest, some Midwestern growers are also trying to evaluate yield loss in soybeans due to off-target movement of dicamba.

Stephanie Porter, a sales agronomist with Burrus Seed, says she’s seen and heard reports of yield losses ranging from zero to 40 bushels per acre. But Porter says linking those losses directly to dicamba damage could prove difficult.

“I don’t think there is a good way to evaluate it,” Porter says. “It’s really hard to do comparisons when a lot of the off-target movement that we saw was completely covering an entire field. Comparing it to a nearby field may not be a good comparison.

“People know what their yields have been and I think they’re checking to see what their neighbors’ fields are doing. But again, I don’t think that’s a good, scientific approach to it.”

Porter says there are several other complicating factors involved in determining off-target dicamba damage.

“A lot of it has to do with the concentration—how much hit it or how much off-target movement hit it multiple times,” she says. “There were fields that were actually hit several times because of several spray applications nearby.”

Porter says other factors include the growth stage of the soybean plant at the time it was hit, as well as the weather conditions after the time of exposure or until the end of the growing season.

AUDIO: Stephanie Porter