Wheat yield woes ahead?
Judging from previous experience with a La Niña weather system, wheat growers in much of the U.S. may be facing a challenging production year in 2011, says Mary Knapp, Kansas state climatologist.
“This growing season is going to be very tough on winter wheat in the Central Plains,” says Knapp. “We had very similar La Niña weather conditions during fall for the 2005-2006 growing season, and that was not a very good production period for winter wheat here.”
During a La Niña year, a warm, dry weather pattern will generally persist in the Central Plains from fall throughout winter, as has been the case to date, says Knapp.
“With the dry fall conditions, we've seen fewer wheat plants emerge and less established stands than we usually do from Nebraska to West Texas,” she says. “Looking ahead, we will likely continue to see very little snow cover, with more wind than normal and rapid temperature swings, which will likely make it very difficult for wheat to stay in winter dormancy. This could lead to above-average winter kill. It will also probably cause more dust and wind erosion problems than normal.”
The temperature fluctuations can be quite severe during a La Niña year, Knapp says. “For example, in southwest Kansas, from December 8 through December 21, we had a temperature range from a high of 71°F. to a low of 8°F.,” she points out. “Even in northeast Kansas, we had a temperature swing from 64°F. to 5°F. in a two-day period during December.”
Spring Rains, Temps Critical
If a strong La Niña continues into March, the Central Plains will likely see a continuation of the current dry weather pattern into March and April, says Knapp.
“There's nothing in our weather outlook that shows we'll be filling up our soil moisture levels any time soon,” she points out. “More likely, we will see a gradual increase in the severity of drought. February, March, and April will be the critical periods for winter wheat production. If we get some good rainfall during that time — especially in March and April — it may be enough for the crop to completely recover from a challenging fall and winter. If we do have a wet spring, our winter wheat may actually do fairly well.”
Unfortunately, the current weather outlook for the Central Plains is for below-normal precipitation heading into March, notes Knapp. “So March is really going to be the pivotal month for us for precipitation,” she says. “Typically, the three months of winter precipitation don't add up to what we normally receive in March alone.
“However, the worst-case-scenario would be for mild weather to cause winter wheat to break dormancy in late March or early April and then for a freeze to come in and finish it off, like what happened in 2006.”
An early April freeze is also a worry for south-central wheat producers, says Jeff Edwards, Oklahoma State University Extension small grains specialist.
“For the 7.5 million acres of wheat in the Southern Plains, we typically don't have a lot of snow cover,” he says. “So in our situation, we're more concerned with wheat breaking dormancy right before a cold snap than we would be about winter kill from lack of snow cover.”