Pantagraph.com Weather forecast, local radar and more
NewsWednesday, July 25, 2007 9:23 PM CDT
Comments Comments (6) | E-mail this page E-mail this page | Print this page Print this page | Enlarge type Enlarge type | Reduce type Reduce type | Search archives Search archives | RSS RSS feeds | Add to My Yahoo! Add to My Yahoo!
Hot enough for ya? It could be sweaty corn
By Bill McAuliffe
Star Tribune (Minneapolis)
Advertisement

MINNEAPOLIS -- The sun and the rain decide how high the corn grows, every farmer knows. But can cornfields talk back to the skies and change the weather?

Climatologists are beginning to build evidence that agricultural crops, and particularly corn, are driving up dew points as they sweat buckets of water into the atmosphere. They also may make corn-growing areas cooler and alter rain patterns.

Some also say the extra moisture could add energy to thunderstorms. One study even argued that a 2001 tornado in Benson, Minn., got a power boost from corn evaporation.

With the nation’s largest corn acreage since World War II standing tall and green in the fields, its effects on the weather have climate experts talking.

“I think there’s a new realization that there is a two-way interaction between weather and agriculture,” said Richard Raddatz, climatologist at the University of Winnipeg, who has studied the transformation of the Canadian prairies from grassland to cropland.

In some ways, researchers are taking a second look at a 19th century adage — “rain follows the plow.” Popularized by Charles Dana Wilber in an 1881 book touting the agricultural promise of Nebraska, the phrase supported a grand notion that the western Great Plains, which in the early 19th century had been labeled the “Great American Desert,” could be transformed into a garden, if only people would expose the moist soil to the atmosphere.

Rainy years added credibility to the idea, and homesteaders flooded the plains. But when the rains reverted to a more normal pattern, thousands were trapped by drought and bankruptcy. And “rain follows the plow” was discredited as pseudoscience.

Wheat on small pioneer farms didn’t change the weather the way Wilber predicted. But Raddatz said there is a growing body of research indicating that contemporary crops do indeed change the way water, heat and energy interact with the atmosphere.

By “transpiring” more heavily than the prairie grasses that preceded them, and in relatively short periods, crops can generate air movements that can lead to storms, and intensify the season during which water is cycled through the atmosphere.

Raddatz published a summary of studies of cropping and weather in February in the journal Agricultural and Forest Meteorology. They add some oomph to a 2002 study of dew points by Northern Illinois University climatologist David Changnon, which pinned a 40-year trend toward higher dew points in the Midwest, and record-high dew points during recent heat waves, on changes in farming.

Not all scientists buy it.

Assistant Minnesota state climatologist Pete Boulay points out that in the Twin Cities, average dew points — a measure of water saturation in the air — during three of the past four summers have been below average. And much of the corn-rowed state is now in its second consecutive season of very dry conditions.

But Boulay does believe that a broadly irrigated landscape on the University of Minnesota’s St. Paul campus has contributed to dew points there that are higher than those at broadly paved Minneapolis-St. Paul International Airport.

Peter Robinson, director of the Southeast Regional Climate Center in North Carolina, has studied dew-point trends nationally and found mixed results, including an upward nudge in corn-growing areas. But he said he is only “suspicious the two are related.”

Wayne Hallcock, whose family has farmed since 1912, was open to the idea that corn might affect weather.

“Why couldn’t it?” he said, while noting recently that his soldierly 8-foot-tall corn could use a boost from a timely rain.

Hallcock said he now has 34,000 corn plants per acre, compared with the 16,000 he used to plant with his father back in the 1970s. The corn and soybeans, some of which are now 10 inches apart instead of 30 as they were years ago, now often remain wet with dew until noon on dry days, which has been a change. But he said no one in his family has ever noted that the air is cooler on his farm — one effect, due to evaporation, that’s been measured in irrigated areas.

“I always thought it was hotter in the cornfield,” he said.

University of Oklahoma climatologist Jeff Basara, who has spent most of his summers in Minnesota, traced a link between corn evaporation and an F2 tornado that injured seven people in Benson, Minn., on June 11, 2001.

“There was going to be severe weather that day. But evaporation added enough moisture to the atmosphere and turned it from a day of localized severe weather reports to a day that really was a headline-maker,” said Basara, who published his research in the Bulletin of the American Meteorological Society in 2005.

Changnon, the Illinois researcher, found that since 1950, crops had replaced thousands of square miles of pastureland during the era of rising dew points. More significant, he said, was the shift in corn-planting from 40-inch rows to 30-inch rows.

“We’re just pouring more water into the air,” Changnon said.

Changnon said the results of his study shouldn’t demonize agriculture, but should prompt urban areas to be alert to the public health threat dew points in the 70s or higher can bring.

(c) 2007, Star Tribune (Minneapolis)

Distributed by McClatchy-Tribune Information Services.

Take a look
Corn grows in a field off Russia Road in Russia Township, Ohio, Wednesday, July 11, 2007. (AP Photo/The Plain Dealer, Thomas Ondrey)
Video
Most commented stories
Browse online archives
Recent issues:
Reader comments on this story - 6 total

Note: All views and opinions expressed in reader comments are solely those of the individual submitting the comment, and not those of the Pantagraph or its staff.

Thanks Ethanol Farmers wrote on Jul 25, 2007 8:01 PM:

" Looks like we're paying for your handouts in more ways than one! "

Uncle Andy wrote on Jul 25, 2007 6:20 PM:

" Don't forget Volcanos (one large volcano produces more "greenhouse" gasses than thousands if not millions of cars) and solar activity. In the same way that one or two variables have little effect on the economy, one or two variables have little effect on the environment also. "

The Joker wrote on Jul 25, 2007 3:20 PM:

" Not possible! This is junk science. Storms cannot increase in intensity due to corn sweating. Sorry folks, can't happen. Al Gore told me personaly that it is global warming that is influencing all our weather. When confronted by dissenting facts, do what most people do, plug your ears with your fingers, chant the chant, and hope the heretics go away soon. "

Mad Scientist wrote on Jul 25, 2007 3:12 PM:

" Ah ha. So this pesky reporter has uncovered my plot to reverse global warming by encouraging people to plant corn from fence row to fence row - thereby lowering the average temp. and saving us all. I don't know why Al Gore hasn't thought of this yet, it's a win-win for everybody. "

Reader99 wrote on Jul 25, 2007 3:11 PM:

" Man global warming now this global wetting? "

Radichris wrote on Jul 25, 2007 3:05 PM:

" Get Al Gore on this immediately! "
Add your own comments

Please read the rules before posting comments.

You must be logged in to leave comments.
If you don't have a member ID, please register.

*Member ID:
*Password:
Remember login?
(requires cookies)
  Forgot Your Password?
 
Lee Enterprises Customer Service | 301 W. Washington St., PO Box 2907, Bloomington, IL 61701-2907 | Ph. 309-829-9000 | 800-747-7323
Copyright © 2008, Pantagraph Publishing Co. and Lee Enterprises. All rights reserved. | Terms of Use | Privacy Policy