Tabletop display demonstrates importance of soil management

SPRINGFIELD, Ill. — A Natural Resources Conservation Service display brought the field to the Illinois State Fair.

The tabletop display demonstrated the interaction between water and soils with different characteristics and management practices.

The infiltration demonstration featured two Ipava soils taken about 500 feet apart from a Morgan County field — one in conventional tillage, the other minimal tillage with year-round cover.

The other two samples were loess soils, one being silty loam adjacent to a woodland, the second was from a yard in Springfield.

The same amount of water was applied to each of the four displays, showing the differences in runoff based on the soil.

Marc Zucco, NRCS resource soil scientist who covers 26 counties in west-central Illinois, began the demonstration comparing the differences in the two Ipava soils.

“The main difference in the Ipava soil is the actual management. One has no cover and conventional tillage with corn and soybeans and looks like it’s sort of sealing over,” Zucco said.

“The other is soil that has been under minimal tillage for 15 to 20 years with an extra crop in the crop rotation — corn, soybeans and wheat. It also has had cover crops and they graze the cover crops. So, it’s kind of a Cadillac plan of conservation. We drip water onto the soils to kind of simulate rainfall.”

The display, located adjacent to the Illinois Department of Agriculture’s tent, had a steady flow of visitors from the time the gates opened.

Living System

Zucco explained the soil/water interaction to booth visitors.

“Soil is a living system of organisms. It’s breathing, it’s respirating and the microbes are fed primarily by living roots,” Zucco said.

“Those roots give off exudates and they feed a variety of organisms which then they exude glues that hold the soil particles together and it creates pore spaces in the soil that allows water and roots even to get down into soil profile.

“That allows pathways for the water to move down deeper into the soil which then stays there longer in the organic matter and is available for crops.

“Tillage has broken up the soil structure in the other sample. The broken-up particles fill in the voids and it basically seals the tilled soil and it runs off, carrying particles with it.

“If this was a field, it would be running off into a waterway and moving, whereas the water infiltrates the soil with conservation practices.”

The other two samples were silty loess soils that were included in the demonstration to offer another comparison.

“One is a silty loam kind of soil. It’s marginal soil on the edge of a field that’s been under trees for a very long time, and the other is from a yard in Springfield that’s also a loess. The runoff is a lot clearer,” Zucco said.

“One thing with this one being that it’s in a yard, the top grass is being mowed because it’s in a yard. So, the root systems are there to allow infiltration. While it does appear to have a lot of infiltration, it won’t go nearly as deep as soil that has the bigger crops that have deeper, more extensive roots.

“We’ve found this to be a nice little display. They’re virtually exactly the same soil. It’s very, very close. It’s the management that makes a difference.”

This was the first time this display has been featured at the fair, at least in recent times.

“We’ve had quite a few people come through here and have had little groups to talk to ever since we’ve been here since before 8 a.m. It’s going well,” Zucco said.