Soils of the Lakeshore Nature Preserve

Photo by Cathie Bruner.

Some people might think it odd to mark on the map of the Lakeshore Nature Preserve three holes in the ground in the middle of Bill’s Woods, but these soil pits are in fact much more interesting and important features than they first seem. Generations of UW students have made pilgrimages to these holes in the ground to learn about Wisconsin soils. The well-known geographer and soil scientist Francis D. Hole once remarked that among the things he most cherished about the lands of the Preserve was the way they gave “all children and their parents and grandparents a chance to enjoy the soils of their native landscape.”

So how did these soil pits come to be in Bill’s Woods? Here’s their story as told by Professor Cynthia Stiles of UW-Madison’s Department of Soil Science:

There are three soil pits in Bill’s Woods, and they are an important learning resource for all who are interested in natural systems. Soils are the foundation on which life thrives, and they are just as varied in appearance and characteristics as people.

The three soil profiles shown in these pits represent typical soils for the glaciated part of Wisconsin. On the top of the hill (at Soil Pit #1) facing to the northeast, the topsoil is thick and loamy over rocky sub-soil formed from two glacially-derived parent materials, loess over till. Near the summit of the hill (at Soil Pit #2), the soil is thin and sandy, with dark topsoil lying directly on the reddish rocky till. The soil at the base of the hill on the south-facing slope (at Soil Pit #3) is deep with a relatively thin topsoil layer over many clay-enriched horizons. This soil is most common in the hardwood forests of central Wisconsin and many other areas in the Midwest.

These soil pits were excavated more than fifty years ago. As humble as they may appear, the pits have a rather grand history. In 1960, they were a significant part of a field trip for the 6th World Congress of Soil Science, held in Madison. During that meeting, soil scientists from the United States introduced a soil classification system, known as the 7th Approximation, that eventually served as the basis for our current Soil Taxonomy and for many soil classification systems around the world.

Today, the pits continue their educational role as a training model for classes in Soil Science, Geography, and Geology. They show us that soils support life and have distinct differences depending on their setting-differences that play important roles in sustaining different ecosystems.