Last week's bitter cold took a toll on some US hard red winter wheat fields, burning back leaves and potentially eating into production potential, wheat experts said on Tuesday.
The damage was expected to be most severe in drought-stricken areas of Texas and Oklahoma, where a lack of adequate soil moisture and poor plant health due to the dry conditions made the crop particularly vulnerable.
"We'll probably get a lot of leaf burn back, especially in the Rolling Plains and High Plains of Texas," said Texas A&M University agronomist Gaylon Morgan.
The Texas Agricultural Statistics Service said in a report issued Monday afternoon that "death losses in recently emerged small grains were extensive due to the extreme cold temperatures." Sixty-three percent of the Texas crop was rated in poor to very poor condition by the state service.
The concerns for the new crop come after temperatures dipped to the sub-zero and single-digit levels for more than 48 hours last week throughout the Plains states. The sustained cold can be deadly to a wheat crop, particularly in poorly emerged, dry fields.
But damage is often hard to assess immediately. Despite the moniker, "winterkill" doesn't always kill off a plant immediately, sometimes leaving the damage unclear until the spring when the weakened plant becomes vulnerable to disease.
Yield impact varies. A study conducted by Kansas State University agronomist Jim Shroyer found that a field with 50 percent winterkill, for instance, would see about a 14 percent drop in yield, while one suffering 75 percent winterkill damage showed a 47 percent drop.
Though the extent of damage in this year's crop is still unclear, some loss is almost assured, wheat experts said.
"With the kind of stresses we were under it wouldn't surprise me," said Mark Hodges, Oklahoma Wheat Commission executive director. "It's been so dry."
Indeed, one aggravating factor is the extreme dryness through the Plains. According to a federal drought report posted December 8, conditions in Texas and Oklahoma ranged from abnormally dry to extreme drought, meaning wheat plants were particularly vulnerable in those key production states.
That comes after the month of November ranked as the fourth driest and 11th warmest on record for the US Plains, according to federal climatology data.
In Kansas, the top US wheat-growing state, the northern part of the state was abnormally dry, but the rest of the state had adequate moisture. Still, there are worries there.
"I'm concerned where there wasn't snow cover," said Kansas State's Shroyer. "I wouldn't be surprised if we see some damage."