- A large part of the Texas winter wheat crop could have been damaged by hard freezes March 24-26.
- The exact extent of the damage won’t be known for five days to a week or longer.
- Much of the wheat in the eastern part of the state suffered from a droughty fall and did not emerge until January.
Extremely cold weather can damage the vegetative parts of wheat, but symptoms, such as yellowing of tillers, may not appear for a week or more, according to a Texas A&M AgriLife Extension Service agronomist. Wheat can routinely take temperatures down to 5 degrees or so without vegetative damage, but heads are more susceptible to temperatures in the 20s and low 30s.
A large part of the Texas winter wheat crop could have been damaged by hard freezes March 24-26, according to a Texas A&M AgriLife Extension Service expert.
“Temperatures in the teens and low 20s appear to have been common in the Panhandle, and in the upper 20s and low 30s in the Blacklands on Sunday night and Monday morning,” said Dr. Travis Miller, AgriLife Extension agronomist and Texas A&M University soil and crop sciences associate department head. “These temperatures are sufficiently cold to cause severe injury to wheat in advanced stages of growth.”
The exact extent of the damage won’t be known for five days to a week or longer, and another hard freeze was expected in the central areas of the state on the night and early morning of March 25-26, Miller said.
A hard freeze can kill individual developing seed heads, he said. Throughout the state, wheat was in various growth stages and each plant has multiple tillers of different ages, he said.
Wheat, when the heads are in an early stage of development, can tolerate temperatures as low as 20 degrees for a few hours without much damage, but wheat in bloom can suffer significant injury from 32-degree temperatures, Miller said.
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Further complicating damage assessment, temperatures registered by nearby thermometers may not reflect actual field temperatures, all of which makes on-the-ground field scouting necessary.
“Temperature may vary several degrees in a field,” he said. “Freeze damage is always worse in low spots in fields. It might kill the older heads and not the younger heads. It’s a real mixed bag out there, a real hodgepodge.”
Miller noted that it was a mixed blessing that much of the wheat in the eastern part of the state suffered from a droughty fall and did not emerge until January.
“I don’t expect that late-emerging wheat will be far enough advanced to be injured, but this late wheat has a lower yield potential than wheat that germinated in the fall. When it emerges late, it has lower potential yields due to fewer tillers and a greater risk of exposure to heat during critical growth stages.”
A month ago, Miller predicted a below-average wheat crop for the Texas South Plains, Panhandle and Rolling Plains because of a dry fall and problems with emergence.
At that time, he noted that Blacklands wheat — from the Metroplex north and east — looked good, being in better shape than anywhere else in the state. Now that wheat is at risk too because of the freezes, he noted.
“It’s a large and complex problem out there,” he said. “But if you had wheat that was blooming and your temperatures got down to 26, you’re going to have some injury.”
More information on the current Texas drought and wildfire alerts can be found on the AgriLife Extension Agricultural Drought Task Force website at http://agrilife.tamu.edu/drought/.