Signs of a drought in Iowa?

http://www.omaha.com/article/20100615/NEWS01/706169929

Signs of a drought in Iowa?

MCCLATCHY NEWSPAPERS

It's hard to think of drought with rivers and creeks running bank to bank with recent rains, but that is just what an Iowa State University Extension climatologist said could happen.

Iowa is long overdue for a major drought, said Elwynn Taylor, and there are signs it could happen this year.

Taylor said the state averages an extended dry spell every 19 years. Tree rings from the past eight centuries prove it, he said.

Despite ample moisture the past six months, history and emerging weather patterns indicate the spigot could abruptly shut off.

Taylor, who's also an agronomist, said the longest time between droughts is 23 years. The last one was in 1988 {So it’s been 22 years since 1988 drought}.

“Yes, we're certainly due looking at history,” Taylor said. “A lot of people would be happy if it was dry next week, but not for six weeks (or more).”

The most substantial drought indicator is the developing weather phenomenon called La Niña, Taylor said. Pacific Ocean temperatures are cooling, which often leads to dry and hot weather in the Midwest. Taylor expects on official start of La Niña within weeks.

Other drought indicators include:

Ÿ A partial low-pressure system in the Gulf of Alaska. Low pressure redirects moist air from that area to the Yukon instead of the Midwest.

Ÿ The Carolinas are abnormally dry. Sixteen of the last 17 droughts affecting the Corn Belt started in those two states.

While there are plenty of reasons to believe a dry summer is ahead, Taylor said it's not a guarantee. He said Bermuda high pressure is still pushing moisture north out of the Gulf of Mexico. That supplies 80 percent or more of the region's rain.

Matt Sorensen of Waverly hopes he doesn't have to turn the irrigation system on to water corn along U.S. Highway 218. But if he does, at least he can stave off disaster in one field.

“It will be up to Mother Nature. I won't lay awake at night worrying about it,” Sorensen said.

If La Niña kicks in, which Taylor expects, the chances of below-average yields increase from 50 to 70 percent, he said.

The U.S. Department of Agriculture predicts corn and soybeans this year will average 163.4 and 42.9 bushels per acre, respectively.

Government statistics show corn and soybeans statewide averaged 84 and 31 bushels per acre, respectively, in 1988.

Taylor said advances in plant genetics and breeding have substantially increased yields since the '80s, but the percentage of yield loss endured by farmers during a drought would still be the same.

A drought also occurred in 1983, resulting in similar yield losses to '88. Taylor said this year is eerily similar to 1983, when El Niño — the warming of central and eastern waters in the tropical Pacific, which often brings moisture locally — turns into a La Niña.

“It was wet to start out with and by the middle of July, it was bone dry and hot,” Taylor said. “This is as rapid of change I've seen since 1950.”

Waverly farmer Bob Busch remembers the droughts of the '80s well. He doesn't want a repeat performance.

“A lot of people collected or were on the threshold of collecting crop insurance; '88 was the worst,” Busch said.

If the summer turns dry and hot, Busch is more worried about beans than corn. There's enough soil moisture to get corn through the critical tasseling period in mid-July he said, but it could run out by the time soybeans fill and set pods a month later. Corn is also more drought-resistant these days, he said.

He's taking Taylor's warning seriously. Busch is making sure fields are clean so weeds don't compete for water and is scouting for pests early.

“I can believe the weather could switch,” he said.