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Weekend temps could deal killer blow to some Plains wheat

Missouri's wheat crop is suffering "unprecedented weather conditions" and a significant portion may not survive the weekend's cold temperatures, according to University of Missouri (MU) scientists.

"The crop is in for some rough weather, and the effects from long-term and repeated exposure of jointed wheat to temperatures in the teens is not often researched," MU Extension agronomist Bill Wiebold says in a university report. "We really know little about the possible effects of this weekend's weather."

Temperatures are expected to dip into the low 20s and upper teens during the nights of April 6-8.

Wiebold says much of the Missouri wheat crop is past jointing -- the stage where the immature wheat head, or spike, has begun to grow above the leaves.

"With the warm weather we had in March, the crop has really sped along. Those tiny heads are now six to eight inches above the soil surface and very vulnerable to freezing temperatures," Wiebold adds.

He recommends wheat producers scout fields after the cold spell pushes through to examine the extent of crop damage. While wheat leaves will likely appear dark and injured fairly quickly after the frost, spike damage will take a day or more to show.

"Probably by late Monday or Tuesday, the crop will begin to show signs of spike damage," Wiebold says. To examine the tiny heads, growers need to slit the main plant stem from the soil to the tip. When healthy, the tiny wheat head and nodes, near the top of the stem, will appear white to light green and be firm and moist.

Damaged heads will appear dark, and "turn to mush," he said. "After a few days they will even begin to smell rotten."

Such damage isn't uncommon in Missouri, though typically frozen wheat spikes are limited to a few low spots in a field where extra-cold air sits long enough to freeze the tissues.

"This weekend, temperatures could freeze the entire field, not just low spots. Those are conditions we just don't see often enough to know how much damage to expect."

Wiebold said if farmers find damaged heads across most of the field, the crop is likely ruined.

"What we don't know much about is the survivability of secondary wheat tillers, which normally stay dormant during a typical crop year," Wiebold says. "Those tillers can produce wheat heads when the plant's main stem and spike is killed. Whether those secondary spikes survive this intense cold, and how much wheat yield they would produce if they do survive, is unknown."

Secondary tillers are the plant's survival mechanism, so that some seed is set. They typically don't produce the high yields as does the primary spike.

It would be weeks before such tillers break dormancy and begin to grow, Wiebold says. Until then, it is impossible to tell if they survived.

"Chances are if you slit open the stem and find freeze damage from the tip down to the soil level, those secondary tillers are gone, too," Wiebold says.

The only good news is that the season is still young enough to allow farmers to destroy the wheat and plant corn. "Most producers have already applied spring nitrogen, so a corn crop can take advantage of that," he says. Troubling, though, is that corn seed supplies are already tight from higher than normal corn plantings due to high corn demand from ethanol production and other uses.

Before destroying a field, farmers should first contact their crop insurance agent, says Rebecca Davis, director of the USDA Risk Management Agency regional office in Topeka, Kansas.

"If you plan to plant that field in corn, you will be eligible for only 35% of the insured wheat indemnity right away," Davis says. The subsequent corn crop would likely be eligible for crop insurance. If it makes a successful yield, the farmer could then recover the full wheat indemnity payment.

"If the corn crop is damaged as well, you keep the 35% loss payment on the wheat crop and collect on the corn indemnity, or waive the corn indemnity and collect the remaining 65% of the wheat indemnity," Davis says.

Missouri's wheat crop is suffering "unprecedented weather conditions" and a significant portion may not survive the weekend's cold temperatures, according to University of Missouri (MU) scientists.

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