Super Soils

In the fourth century BCE, the ancient Greek philosopher Xenophon wrote, “To be a successful farmer, one must first know the nature of the soil.” More than 2,400 years later, we still haven’t uncovered all the mysteries of soil — and a team of researchers here in Washington is dedicated to learning and sharing everything they can about this life-sustaining material.

While we might not think much about the dirt under our feet, soil is crucial for the survival of our ecosystem. It provides nutrients and stability for the plants we grow, regulates the flow of water, filters pollutants, breaks down organic and inorganic materials, and even
helps keep our homes standing upright.

“Soil is the foundation of everything we do,” says Gabe LaHue, an assistant professor of soil science at Washington State University (WSU) and a researcher with the Washington Soil Health Initiative (SHI), a partnership between WSU, the state department of agriculture, and the State Conservation Commission.

The initiative’s programs include agricultural research, technical support, and outreach and incentive programs for farmers and growers. In Mount Vernon, LaHue and a team of researchers grow crops and conduct experiments to see how they can improve the soil underfoot.

“We’re tracking the yield and quality of all the crops we’re growing,” says LaHue, whose focus is to make sure the crops that are grown on the research site use the same techniques that farmers use. “Then every year, we test the soil, and then every four years, we come back, and we do a really intensive sampling. That really helps us get a comprehensive picture.”

Chris Benedict, WSU’s faculty lead for the initiative and a professor at the university’s Whatcom County Extension, says the program looks at long-term practices and opportunities to improve soil health.

“This is big-picture stuff,” Benedict says. “It will give us the ability to really look at what changes in the long term.”

This is especially important in Washington, where our vibrant agricultural community and our specialty crops rely on the state’s rich soil. There are many different types of soil throughout the state, depending on each region’s climate, but one special variety, called Tokul, is one of the most productive soils in the world, thanks to its high amount of volcanic ash. This mineral-rich soil can only be found west of the Cascade Mountains and was named Washington’s official state soil, joining the ranks of the American goldfinch (the state bird) and the western hemlock (the state tree).

Working with soil can be a slow process, said LaHue, but it’s rewarding. “The whole reason this is a long-term experiment is because soils are slow to change,” he says, “but the exciting thing is we’re already starting to see some differences.”

Deirdre Griffin LaHue is another researcher at the initiative’s Mount Vernon site and an assistant professor of soil science at WSU. Her interest in soil came, surprisingly, from her background as a dancer.

“I had a previous career in ballet, so there was a career transition, but through that, I got interested in nutrition,” she says. “I realized, through that, I was really interested in where it comes from — from the soil.”

Griffin LaHue’s research mainly focuses on how soil can break down organic matter, and how quickly the organisms growing in the soil can decompose materials. This, in turn, affects how many nutrients are available to the crops growing there. One experiment they use is called the T-shirt test, where two cotton T-shirts are buried in the soil for three weeks before being dug up.

“So I had two T-shirts here that I buried in the soil,” says Griffin LaHue, holding up two plastic bags with labels reading “Fallow Field” and “Alfalfa Field.” “One is from a field that was just left without any crops and was heavily tilled, and one was from a field that had a lot of organic matter input — continuous crops in it.”

Griffin LaHue holds up one of the shirts, which is dirty and has a few small holes throughout but is generally still intact. This shirt was buried in the field without recent crop activity.

“In this field, there was some action going on; there were some holes in that shirt, so they did a pretty good job breaking down,” she says. “But when we unburied the one from the other field, this is what we found.”

She then holds up a remnant of a T-shirt that looks like it’s been devoured by a bear: the collar and one sleeve are intact, but the rest of the shirt is in shreds, and large chunks are missing. This shirt was buried in the second field.

“So you can see the organisms in that soil are just ready to break down any residues that are going in, turn it into soil organic matter, turn it into nutrients that crops can then take up and then really benefit the soil.”

The more we know about how these microorganisms and nutrients affect the soil, the more we can use that to grow healthier, more abundant crops, something the team at the Soil Health Initiative knows is crucial for our survival.

“Our ecosystems rely on soil; our food systems rely on soil,” says Griffin LaHue. “Something that’s happening within this little piece of soil can have an impact on the globe.”