Eons at the verge of prairie and forest created “Lester”

The highly productive, clayey soil now designated “Minnesota State Soil”

Written by Jonathan Eisenthal

Some 400,000 acres, across 17 counties in south central Minnesota are home to some of the most productive soil on earth, called Lester soil. Legislation signed in April by Gov. Mark Dayton recognized Lester as the state soil of Minnesota, and a series of programs to celebrate Lester and all of Minnesota’s soils is now underway, including an exhibit called Dig It!, opening Nov. 10 at the Bell Museum of Natural History at the University of Minnesota’s Minneapolis campus.

“Lester is well drained, with a nice, thick ‘a-horizon’ — that black surface soil,” said Gary Elsner, a soil scientist at Minnesota Department of Agriculture. “There are a thousand different soil series in Minnesota. Lester is in the well-drained positions which are higher in the landscape (Slopes 5 to 70 percent).”

Elsner chairs the “Perfect Storm for Minnesota Soils” committee of the Minnesota Association of Professional Soil Scientists (MAPSS), which singled out Lester soil as something special back in 1987, but did not succeed in getting the official state seal for it until this year.

“Lester soil formed at the prairie and forest interface,” Elsner said. “Most of southern Minnesota soils were worked around by glaciers, and they have been forming ever since. A forest forms and that influences the soil, then a forest fire clears the land and it becomes prairie. Over a very long time period, it goes back and forth. In forested land you get clays near the surface, and over time these leach down and they accumulate deeper in the profile. So you get a layer that has a higher water-holding capacity and that makes it more productive–both for agriculture and forestry.”

“The Perfect Storm for Minnesota Soils” committee of MAPPS arose to publicize the series of important soil science events taking place last year, this year and next. Ultimately, the committee hopes to use these events to make the public more aware of the incredible importance of productive soil in their everyday lives. The roster of events shows that concern for the health of our soils is nothing new among farmers, foresters and soil scientists. In 2011, it was the 75th anniversary of the Soil Science Society of America. This year is the 150th anniversary of the USDA (inaugurated by Pres. Abraham Lincoln). In addition to successfully passing the soil legislation this year, the University of Minnesota’s Bell Museum has a new exhibit, Dig It!, devoted to soil and including soil “monoliths” (glass columns showing the stratifications within soil series like Lester) for all the official soils of the 50 states. The exhibit opens Nov. 10.

For more information on Dig It! go to http://www.bellmuseum.umn.edu/ForAdults/Exhibits/DigIt/index.htm

The soil events continue, according to Elsner. Next year is both the 100th anniversary of the University of Minnesota Department of Soil, Water and Climate, and the 40th Anniversary of MAPSS. Various tours and special events at locations like the Minnesota Landscape Arboretum are planned.

Elsner noted that MAPSS chose Lester soils for a number of reasons, including that it is photogenic, but its water-storing capacity may be its most important feature, especially in drought years such as Minnesota experienced in 2012 and 1988.

“Whether you’re growing a tree or a corn plant–if you have more water it’s going to grow better,” said Elsner. “When you compare to a sandy soil, you can see how Lester holds more water, and it will do better at producing healthy plants than the sandy soil, when we have dry weather conditions.”

Lester soils were first identified in Lester Prairie, in McLeod County in 1939. According to MAPPS, soil supports 235,000 jobs in Minnesota. Roughly one hundred scientists belong to MAPPS, including state and federal government workers, academics and private industry workers.

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