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This is some pretty special dirt

The unique collection of intact soil cross-sections is both a piece of history and a ‘priceless’ educational tool

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A decades-old collection of ‘soil monoliths’ donated to Lethbridge College will be an invaluable tool for teaching students about soil.

The 110 monoliths are vertical cross-sections about one metre long that show soil from a variety of regions in its natural state. Long been housed at Agriculture Canada’s Lethbridge research centre, the soil monoliths have been appraised at $240,000, but are worth much more, say college officials.

“It’s priceless as a way to show our students the greater diversity of soils from a much larger region than we could visit on our own,” said Edith Olson, Lethbridge College Agriculture and Environmental Sciences instructor.

“They have practicality, which ties in beautifully with the educational goals of the college, which is presenting the strong theory, the science, and the physical learning environment so that we can actually help in the real world.”

The collection, containing eight out of the 10 official orders of soil, come from across Western Canada. The value of the collection as a teaching tool was first recognized by longtime college soils instructor Ken Perl, who has frequently taken classes to the Lethbridge research centre. He was involved in the initial talks to bring the collection to the college, a process that took many years.

Each of these long vertical cross-sections of soil has many tales to tell about soil formation, climate, the local ecosystem, and natural history. photo: Lethbridge College

“I would take students over there on field trips in our soil classification and taxonomy class,” said Perl. “It was integral to my course to show the students that soil isn’t just something you dig up and arbitrarily manipulate, it has many different classifications.

“If you stretch your imagination, soil really is a living, breathing organism like a coral reef and really just as complex.”

The history of the collection is something of a mystery. It’s believed that federal and provincial soil surveyors likely created the collection over a number of years in the 1950s and 1960s, but there is little historical documentation about the collection. The soil samples are largely from southern Alberta, but also include soils from elsewhere in the province as well as from Saskatchewan, B.C., and the Yukon Territory.

Each one is as unique as a fingerprint, and the effort that went into creating the collection was enormous.

“A considerable amount of resources, staff, labour, travel, and time would have been invested in building this collection,” said Jim Miller, a federal research scientist at Lethbridge centre. “Some of these would have been remote locations. You’ve got to travel to the sites, dig a huge soil pit and carefully cut out and excavate a large intact soil monolith.”

The process of mounting the monoliths is also arduous, as each has to be carefully placed on a backboard while preserving its physical features — a meticulous combination of art and science.

“It is a very slow and delicate process to excavate an intact soil monolith and a lot can go wrong and then you might have to start over,” said Miller. “In addition, it is a very laborious and delicate process to fill the soil pores with epoxy resin or glue back in the laboratory to ensure the soil structure remains intact and doesn’t fall apart.

Miller likens the collection to a form of taxidermy.

“A soil monolith collection is analogous to a natural history museum, but instead of preserved animals or plants, you have preserved intact soil monoliths,” he said. “Soils are not classified as species like animals and plants because there is a gradation of soil types in natural landscapes and soils are not discrete units like animals and plant species.”

To Perl, the monoliths’ value is their ability to fill in the blanks where a literal field trip — when he and his students would dig into the ground — falls short.

“We could only do one or two soil types on a field trip,” he said. “But these are fantastic because they represent all of southern Alberta and beyond.”

After taking so many classes to see the monoliths, Perl is now recognized as the resident expert on the collection.

“People would say, ‘That must get boring,’ but I would say, ‘No, every time I look at those, there’s some other detail, some value-added insight,’” he said. “It’s amazing how you can look at them in a different light and say, ‘This is what that profile is telling us, not only about the soil resource, but also the climatic and ecological conditions that shaped the soil, and in turn how the soil affected the related ecosystem.’”

The collection is now on display on the third floor of the Cousins Building, right outside of the college’s soils lab.

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