Better corn weather?
Sometimes the past can be prediction. For much of this summer, Iowa State University climatologist Elwynn Taylor saw erie similarities between the wet spring and dry summer of 1947 and this year's weather patterns in Iowa and parts of the western Corn Belt.
"Right up until this week, it could have been a carbon copy," Taylor said Tuesday at the Economic Summit held by the Iowa Farm Bureau Federation in Ames, Iowa. That year brought the fourth-worst crop production in Iowa history.
What local meteorologists called a "flash drought" seemed to end when a wide band of showers, hail, and wind swept down from the north on Monday evening. It left about an inch of rain behind in Ames, falling to a half-inch in the Des Moines metro area, and dissipating before the front reached the Milo, Iowa, farm of a disappointed Iowa Farm Bureau president, Craig Hill.
As Midwestern farmers know all too well, 2013 has been a year of extremes. Taylor recapped some of Iowa's highlights: Record-breaking snow over almost a third of the state on May 2; May 14 temperature records ranging from the upper 90s to over 100; and record flooding in the Little Sioux River in Cherokee, Iowa, on May 27.
"Extremes seldom benefit crops," Taylor told his audience at Iowa State University's Scheman Center.
Wet weather that kept some fields from being planted was followed by dry conditions, with less than an inch of rain falling in July in central Iowa until Monday's showers.
Taylor said that Monday night's rain was enough to fill about half of the top foot of soil profile, not exactly a drought breaker, but it also brought cooler temperatures as the crop is beginning to enter a delayed pollination period.
Taylor said that as soon as grain starts developing, corn root growth stops. The average rooting depth is Iowa is 5 feet, he said. In Illinois, it's 3.5 feet. If the roots aren't long enough to reach soil moisture at tasseling, they won't be, he said.
Soybeans, which have indeterminate flowering, continue to root, he said later.
That may be a good thing, since one of the indicators Taylor follows suggests that the rainy pattern we've entered may not last.
Taylor said that the Pacific Ocean temperature pattern known as La Nina, which features cold ocean surface temperatures off the coast of Peru, appears to be retuning.
La Nina has a correlation with dry weather in the central U.S. and wet weather in western Canada, he said.
"It's likely that in the next three to four days, we will move right into La Nina again," he told Agriculture.com later.
Taylor told his audience that the change may not happen soon enough to affect the corn crop, but it could affect soybeans if it hits during flowering and podfill after corn pollination.
Already, though, Taylor expects 2013 to bring the third year in a row of below-trendline corn yields, which would be 160 bushels an acre nationally.
Taylor doesn't pretend to be a long-range weather forecaster. During questions from the audience, he said he couldn't tell yet whether we'll have an early frost or not.