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July 18, 2003

Rain-soaked wheat could give farmers growing pains

WEST LAFAYETTE, Ind. – Torrential rains in northern and central Indiana earlier this month could give winter wheat crops an unintended – and unwanted – growth spurt.

Wheat heads can germinate if subjected to excessive moisture prior to harvest, said Ellsworth Christmas, Purdue University Cooperative Extension Service wheat specialist. For farmers, the extra plant material means reduced grain value.

"Once wheat dries down to a moisture level for harvest and then gets wets again, head sprouting can occur in some varieties," Christmas said. "Should this occur and should it be severe, the grain will be docked significantly at the elevator and, in some instances, may not even be purchased.

"Millers do not want sprouted wheat. Sprouted wheat means that the wheat kernel itself has been altered. That results in poor quality flour, which has a shorter shelf life and cannot be used for certain products."

Head sprouting is less common in soft red winter wheat, the kind grown in Indiana, Christmas said. So far, unharvested wheat acres in the state's northern and central regions have exhibited few signs of head sprouting. However, the longer farmers wait to bring in their crop, the greater they risk head sprouting, he said.

As of Sunday (7/13) only 10 percent of winter wheat acres were harvested in northern Indiana, according to the Purdue-based Indiana Agricultural Statistics Service (IASS). Farmers in central Indiana had completed 54 percent of their wheat harvest, the IASS reported. Harvest was 97 percent finished in southern Indiana.

Indiana farmers are expected to harvest 420,000 acres of wheat, up 27 percent from 2002, the IASS reported.

Head sprouting is not the only potential problem with late-harvested wheat, Christmas said.

"The other concern we have is that a lot of wheat in northern Indiana shows some evidence of scab. It's variable from field to field," he said.

Head scab, a plant disease, damages grain quality and test weights. The infection also can cause toxins, including vomitoxin, to develop within the grain.

"There have been tests run this season, and they indicate there's vomitoxin in the grain," Christmas said. "Vomitoxin is a very stable toxin. Elevators do not want that grain because it goes through the milling process and into the finished product. If the level of vomitoxin is high, the grain is not very good as livestock feed, either."

Before harvesting scab-infected wheat, farmers should adjust their combines, Christmas said. "The air should be increased on the combine to blow as many of those lightweight tombstone grains out the back of the combine as possible," he said.

The deluge beginning Independence Day weekend that dumped more than a foot of rain on parts of northern and central Indiana couldn't have come at a worse time for wheat growers. Many fields were within a few days of optimum harvest conditions, with grain nearing the ideal 13 percent to 15 percent moisture content, Christmas said.

"Once wheat grain reaches its harvest moisture, each time you wet it and dry it you lose about 2 pounds per bushel in test weight," he said. "Still, since this grain was not quite at a harvest moisture when the rains came, it appears that the wet conditions have not had a significant impact on test weights,"

Christmas urged farmers to finish harvesting wheat as soon as possible.

"Just as soon as the soil is firm enough to support the combine, they need to get it harvested," he said.

Writer: Steve Leer, (765) 494-8415, sleer@purdue.edu

Source: Ellsworth Christmas, (765) 494-6373, echristmas@purdue.edu

Ag Communications: (765) 494-2722; Beth Forbes, bforbes@aes.purdue.edu; http://www.agriculture.purdue.edu/AgComm/public/agnews/

Related Web site:
Purdue University Department of Agronomy


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