Crops Get Knocked Down; Will They Get Up Again? A Look at Yield and Quality Impacts From Early Lodging

Wind and rain have taken a toll on some of the best-looking cereal crop acres in Western Canada and the northern U.S. over the last few weeks. Large sections of wheat, barley and oat fields have been knocked flat (some several times) in parts of southern Manitoba and North Dakota.

Yield losses from lodging can range anywhere from 5 to 40 percent, says Pam de Rocquigny, cereal crop specialist with Manitoba Agriculture, in this video filmed at the Manitoba Crop Diagnostic School in Carman.

“The worst time for the crop to lodge is anywhere in that 10 day to 20 day period right after anthesis. That’s typically when you’ll see your greatest yield losses,” she notes.

A wheat stem "elbowing" to bring the head toward an upright position.
A wheat stem “elbowing” to bring the head toward an upright position.

Lodged plants will kink or “elbow” at nodes along the stem, trying to move the head back into an upright position, explains de Rocquigny. Multiple elbows can be found on stems of persistent plants that have been knocked down more than once (insert cheesy Chumbawamba reference here). The plants’ response may include secondary growth of new tillers as well, making harvest more difficult and using energy that would otherwise go to grain-filling.

Lodging can also impact grain quality, often resulting in decreased test weights — up to 8 percent lower in wheat and 15 percent in oats, she says. At the same time, protein levels might rise.

Depending on timing, lodging can complicate disease control, as it’s difficult to effectively apply fungicide for fusarium head blight when a crop is laying flat. Higher armyworm populations have also been reported in lodged areas. (continued)

So what caused some fields to lodge while others, sometimes seeded with the same variety, didn’t fall flat? Straw strength, height, root health, soil conditions and the crop’s fertility program all play a role in lodging risk, says de Rocquigny, noting rapid growth prior to heavy rains was also a major factor.

“We’re thinking that we saw a lot of the lodging occur because the wheat had just gone through a really rapid growth phase. The stem just didn’t have time to solidify or ‘cure’ in terms of being as strong as it possibly could be,” she explains. “It just happens the wind and rain came at the most inopportune time in terms of crop staging and that’s why I think we see the extent of crop lodging that we have seen this year.”

Plant growth regulators could also serve as a tool in preventing lodging, but de Rocquigny says there are still many questions that need to be answered about how plants respond to PGRs.

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