By Ayrel Clark-Proffitt, Sustainability Resource Center
My grandparents had a vibrant backyard garden in their small town in western Iowa. They grew tomatoes, strawberries, and according to my uncle, some incredibly delicious raspberries. I remember the strawberries best. As kids, we’d go out back and pick some fruit “for dinner,” though the best berries never made it in the house.
Growing up in Iowa, I never thought too much about its most valuable asset—soil. I knew it was black, rich, and that it made Iowa one of the best places for farming in the world. I knew that once upon a time it was prairie. But I didn’t know what kind. The desire to farm or garden didn’t make it to my parents—the only things growing in our yard were grass and dandelions.
Not knowing or even caring about these things disconnected me from parts of Iowa’s rich culture and kept me from considering its changes over the centuries. But on a trip back home in May, I had a chance to dig into its history.
I first started thinking about Iowa soils when I moved away 10 years ago. Living in Arizona, I noticed a funny thing: Crickets in the state were much smaller and much lighter in color than those I grew up with. Field crickets in Iowa are dark brown-to-black, just like the soil. I was again reminded of Iowa’s beautiful dirt when I began my own vegetable garden in Salt Lake City. I spent whole days removing pebbles from the future garden beds with a homemade rock screen; I spent even more time and effort to shift my soil’s needle back from alkaline, which is a common problem in the Salt Lake Valley. Oh, how I wished for Iowa’s black soil.
I was lamenting my lack of Iowa soil, but I wasn’t thinking too in-depth about how Iowa soil became Iowa soil. While visiting the state for graduations, my husband asked me, “Has Iowa always had so many trees?”
The short answer was no, it used to be prairie. Then he asked, “How much of the state was prairie?” I guessed around two-thirds of Iowa was covered by the grasses. But then, he stumped me: “So why are there so many trees now?”
The answer, it turns out, is a web of tallgrass prairie, native peoples, and abundant herds of large beasts, such as bison and elk, and the near-complete elimination of all of them.
Despite growing up in one of the prairie states, I never learned (or have at least forgotten) that there are distinct types of prairie. There are wet prairies and dry prairies, tallgrass and short grass and mixed prairies, too. Iowa was almost entirely covered—about 85 percent—by tallgrass. In our quick online search to understand Iowa’s current vegetation, we discovered the Neal Smith National Wildlife Refuge, about 40 minutes from my hometown. The refuge is a preserve for about 90 acres of remnant tallgrass prairie, and the organization is reintroducing hundreds of prairie plant species to the rest of its area.
According to the refuge, less than 0.1 percent of Iowa’s prairie remains.
Tallgrass prairie can grow up to 10 feet tall, according to educational materials at the Prairie Learning and Visitors Center at the refuge, which we visited on a windy, chilly afternoon. More importantly, its roots can go just as deep. These extensive, intertwining roots are a large component of Iowa’s nutrient-rich soil. Decomposing prairie roots contributed to the deep and humus-rich topsoil, which retains water and nutrients that bolster plant growth. Early settlers found topsoil 14-16 inches deep.
The native people who lived in what is now Iowa should also be credited with the state’s “black gold.” Native Americans likely used fire at the end of summer into early fall to burn the prairies, thereby reducing wildfire danger, increasing visibility, and improving the environment for large animals. Fire encouraged prairie growth in multiple ways: It broke open seed coats, allowed the sun to reach seeds in the soil, and removed less fire-adapted plants like trees that would have shaded the grasses and wildflowers.
The large animals that grazed in the prairie were major beneficiaries of the native people’s fire regimen. Deer, elk, and especially bison roamed the area, eating small seedlings and allowing wildflowers to establish themselves across vast swathes of open prairie. The bison population was estimated to be near 30 million before European settlers arrived, and these large creatures roamed in herds of hundreds or thousands, eating grasses and other seedlings without overgrazing. The Neal Smith National Wildlife Refuge now manages a herd of 70-90 bison on a 700-acre enclosure, where university researchers collect data on how bison impact prairie species.
These key elements, though, are no longer. Native Americans were pushed from the state, settlers plowed up the prairie for farmland, and bison herds were decimated. Iowa is left with beautiful soil, but without the deep roots of the prairie system, it is rapidly eroding.
Having my own garden, where I work my soil and get my hands in the dirt, makes me regret not pursuing one when I was young. I didn’t think about the geology and history that created the soil. I didn’t think about what makes soil great and all the organisms that are a part of it. I didn’t learn my grandparents’ tricks. These connections are important.
Take an active role in developing your roots. Learn about Utah’s soils from the Utah State Extension; discover how to improve Salt Lake soil from Wasatch Community Gardens; and get your fingers in the ground in your own yard, at a community garden, or at the Edible Campus Gardens on the University of Utah campus.
Ayrel Clark-Proffitt is the education and outreach coordinator for the University of Utah Sustainability Resource Center.