A UIUC Researcher Wants to Compare New Farmland Soil Samples to Old Ones. Objective: Learn How Farming Affects Soil Over Time.

By Jim Meadows

A soil scientist at the University of Illinois Urbana campus is reaching out to landowners and farmers, as he prepares to take soil samples at locations where samples were taken years ago across the state.

Professor Andrew Margenot plans to compare the new soil samples with past samples stored at the U of I Crop Science Research and Education Center, better known as the South Farms. He says more than 5,000 samples were taken at 453 sites around the state, in almost every one of Illinois’ 102 counties. The samples date back as far as the 1860s and as recently as the 1990s, although Margenot says most of them were taken between 1920 and 1960.

The soil samples had been stored in various places on the University of Illinois Urbana campus over the years, often in basements and underground tunnels, and usually in a spot near the Main Quad. Margenot says colleagues in the university’s College of Agricultural, Consumer and Environmental Sciences (ACES) were vaguely aware of them, but apparently no one was actively working or keeping track of them in August of 2018. That was when, acting on a tip about ‘jars of dirt’ on campus, he found the soil sample collection in a deteriorating university barn slated for demolition.

“I couldn’t really sleep that night, and I began drafting grants that very same night”, Margenot said, “because it was terribly exciting. It was a resource that I realized we’re lucky that someone held on to. This is the oldest archive in the world, and the largest extant. So spatially, it’s an enormous coverage. This is it. This is the best we have in the entire world.”

Using old soil samples for new research

Since then, the soil samples have been moved to a more secure barn on the South Farms. And with funding from the College of ACES and the Illinois Nutrient Research and Education Council, Margenot has embarked on a multi-year project to take new soil samples in the areas where the old samples were collected. He says such a comparison could reveal how the soil used for growing crops has been changed by farming techniques over the years.

Originally, researchers used the old soil samples to map Illinois soil types. Margenot says soil samples for similar projects in other states have also been preserved, with many stored at a Lincoln, Nebraska facility by the U.S. Department of Agriculture’s Natural Resources and Conservation Service. But he says most of those collection are from more recent years, and nowhere near as old as the UIUC’s collection.

“For example, we can better map the natural occurrence of nutrients in a subsoil across the state,” said Margenot. “And based on that, there are direct implications for agronomic recommendations on things like phosphorus or potassium fertilization.”

Phosphorus and potassium are common nutrients found in fertilizers.