Glaciers Have the Dirt on Illinois' Fertile Farmland
 

BLOOMINGTON - Along with Chicago's soaring skyline and Lincoln's prairie roots, Illinois is best known for routinely producing one of the nation's top yields of corn and soybeans.

Some soil scientists say the state should be as well known for what's behind those yields: rich, black dirt that is unmatched for fertility in the U.S. and equaled by only three other places in the world.

"God didn't make many places as good as this," said Robert McLeese, state soil scientist with the U.S. Department of Agriculture's Natural Resources Conservation Service office in Champaign.

Only patches of farmland in Argentina, southern Ukraine and along the Yellow River in China match the fertile ground that covers much of the northern half of Illinois, particularly a high-yielding band through the state's midsection, state soil experts say.

From Bloomington to tiny Bethany near the banks of Lake Shelbyville, city and chamber of commerce promotions tout the rare earth the way Florida plugs sunshine. Web sites across the region boast the richest farmland in the nation, if not the world.

Those claims are greeted like a late-summer drought across the border in Iowa, which historically ranks with Illinois atop rankings of corn and soybean production.

"Have they not been to Iowa? We'd have to disagree for sure," said Holly Coppola, spokeswoman for the Iowa Farm Bureau.

Both states trace their rich farmland to glaciers that covered much of the region before they began retreating about 12,000 years ago.

The mammoth sheet of ice protected the ground beneath it, essentially making it at least 15,000 years younger than land farther south that remained exposed during the glacier era, soil experts say.

As the ice melted, strong winds handed the land another jolt of fertility. Massive dust storms spread mineral-rich river basin soil more than 100 miles, laying a fertile layer of topsoil ideal for corn and soybeans.

Illinois got yet another boost because glaciers killed off the state's one-time woodland terrain and replaced it with prairie grasses, which feed even more crop-friendly nutrients into the soil, said John Lohse, a soil scientist with the Illinois Department of Agriculture.

"I haven't been to Russia, China or South America, but we can lay claim to having some of the richest farmland in the world here in Illinois," Lohse said.

Soil scientists say the glaciers left prime farmland through much of Illinois north of Interstate 70, which cuts through the south-central part of the state. They say the richest soil is in a swath that runs east from around Springfield to the Indiana border.

That includes Morgan County, which logged the state's first 200 bushel per acre average corn yield last year, and McLean County, traditionally the state's leading corn and soybean producer.

"If it isn't the richest farmland in the world, it's a least some of the richest. ... It's not hype, it's true," said Jeff Squibb, a spokesman for the Illinois Department of Agriculture.

Iowa farm officials, without meaning to take anything away from the drummer clay loam and a few dozen other soil types that help produce Illinois' roughly $7 billion annual grain crop, nevertheless take exception to such talk.

Visit the NRCS Illinois Web site.

"There's absolutely no doubt in my mind that Illinois and Iowa both are both blessed with above-average soils from a fertility standpoint," said Mark Salvadore, a research analyst with the Iowa Farm Bureau.

As evidence, he cited the neighboring states' neck-and-neck yield averages in 2004. Illinois averaged just over 50 bushels an acre for soybeans, compared with 49 bushels in Iowa, while Iowa's corn harvest averaged 181 bushels an acre, topping the 180-bushel average in Illinois.

With rich soils in both states, Salvadore suspects yields are likely influenced most by other factors, such as rainfall and temperatures. He also thinks soil quality is subjective and that plenty of other states could lay claim to having the most fertile ground.

"Kansas could point to its wheat crop," Salvadore said.

By JAN DENNIS
THE ASSOCIATED PRESS