You've heard about the famous prairie soils of Illinois. The prairie actually extends into west central and northwest Indiana, with Benton County containing lots of soils developed under prairie conditions instead of timber. When most people hear of 'prairie soils', they think of flat, very dark, naturally wet soils that are super productive if drained.
Prepare to have your thinking horizons expanded when you visit the Farm Progress Show near Decatur, Ill., on Aug 28-20 this week. The exhibit field, Progress City, and precision demonstration area north of the exhibit field pretty well meet that description. But as you move east toward the back side for the property, or park in the south parking lot east of Richland College, you might be surprised at what you find.
And finding out will be easy. Farm Progress in cooperation with Farm Credit Services, the University of Illinois and Purdue University is holding the third annual (in modern times) high school FFA soils judging contest on Tuesday. Pits will be open for inspection by anyone Tuesday afternoon through Thursday. Look for the University of Illinois flag and small tent at the east edge of the South Parking Lot, southeast of the Monsanto exhibit, to find the practice pit for the contest. Take a short walk due east down the lane between 30-inch row corn to the north and twin-row corn to the south to find the first pit in a 90 curve, located just off the exhibitors route. Then go due south about 200 years. Pits 2, 3 and 4 run alongside the cornfield and into the grassy area, down by the trees, at the edge of the property.
You'll scratch your head once you enter the practice pit, dug 52 inches deep to reveal various qualities of the soil. "These are all prairie soils," says Gary Steinhardt, the Purdue soils specialist responsible for judging the contest. "But all prairie soils aren't poorly drained. In fact, this one is well-drained, with glacial till exposed at the bottom. The parent material is till. Since it's on a level slope, it's class one soil naturally, the highest class possible."
Soils that are wet are usually class 2 in their natural state, but very productive when drained. In fact, Indiana soil judging contest rules actually recommend a higher rate of nitrogen on dark, naturally wet soils than on well-drained, class 1 soils. "It's not because more n should be needed since soils are wetter and nitrogen losses could potentially be higher," Steinhardt explains. "The reasoning when the rules were put together is that the wetter soils likely contain higher organic matter, and are probably more productive when drained than the well-drained soils."
The other pits hold similar surprises. In fact, you won't find the classic, poorly drained, level prairie soil anywhere in the contest area. Compared to timber soils, organic matter would be expected to be higher, but all these soils aren't level either. If you come to the show thinking all you're going to see are dark, wet, level soils that grow 250 bushels of corn per acre just because someone throws the seed out there, think again. You owe it to yourself to take a trip through the pits. Managing these soils for top yields can be as challenging as managing soils for high yields anywhere else.