Some wheat fields were left unharvested throughout parts of North Dakota and Montana last year.
At the end of October, some North Dakota counties had 100 percent of wheat harvested, while some areas had only 60 percent. In fact, some wheat was held over and combined earlier this spring.
“Some farmers who were able to get it harvested had problems at the elevator with the wheat being rejected due to quality issues,” said Joel Ransom, NDSU Extension agronomist in small grains and corn, who recently spoke about agronomic concerns with wet crops.
“We really had a tough year (in 2019), and we’re concerned wheat did not meet quality standards for milling grade,” Ransom added.
Many bushels of wheat were rained on prior to harvest.
Damaged grain can mean low falling numbers and sprouted kernels. High levels of DON, a mycotoxin produced by the fungus Fusarium graminearum, are associated with Fusarium head blight (FHB).
“Anything below 300 (for falling numbers) is usually discounted, and the rate may vary by location and year,” he said.
More than 4 percent of damaged kernels, including sprouted kernels, cause grain to be rated Grade 3 or lower.
“Typically, it would be unacceptable for bread making,” he said.
DON levels above 1 parts per million (ppm) are deemed unfit for human consumption. Discounts usually begin at 1-2 ppm, and generally they can mill out at 1 ppm.
“Discounts don’t usually begin until the grain is a bit higher than 1 ppm,” he said.
What causes low falling numbers?
Most commonly, grain in the head gets wet after it has reached harvest moisture.
Enzymes are then produced that degrade starch, “which makes bread making difficult.”
“It is possible that grain could have low falling numbers without visible germinated kernels, and there have been producers who are concerned about that. They actually have had sound kernels going in (to the elevator) and find they are subject to discount,” Ransom said. “I think it is fair to say if you have visible sprouted kernels, you will always have low falling numbers.”
What are the causes of pre-harvest germination?
“We actually see some sprouting and it is associated with rainfall or high humidity on grain that happens during a period of after-ripening (mature), and kernels have had to dry down to 28-30 percent moisture and then be rewetted,” he said.
Sensitivity to pre-harvest sprouting is variety specific.
“At NDSU, we don’t do any screening for this,” he said. “Reasonably good sources on sensitivity are available from screening at a few universities. If you look at our varieties at NDSU, most of our varieties are fairly resistant to pre-harvest sprouting, but with the right conditions, they will sprout.”
So what should growers do with sprout-damaged grain? According to Ransom, the grain can be used for either feed or seed.
“That is what is on most producers’ minds after harvest where rainfall and moisture caused sprout,” Ransom said.