More than 25% of biodiversity is under our feet — but we're destroying it. A biotech startup that's raised $56 million has a plan to help save our soil.

• More than one-quarter of all species lives in soil.
• Soil biodiversity enables farming, purifies water, sequesters carbon, and more.
• The women-led biotech startup Trace Genomics is working to reverse human-caused soil erosion.

If you've ever held a gram of soil, odds are you had more than 10,000 species at your fingertips.

You might flinch at the thought of billions of bacteria, fungi, and critters at work under our feet, but dirt is home to a living network that can protect crops and humans from disease, purify and conserve water, break down pollutants, and remove carbon dioxide from the atmosphere.

Whether directly or indirectly, we rely on healthy soils for 95% of our food. More than one-quarter of all species lives in soil, and this underground apparatus has a trickle-up effect: Life above ground begins with the microscopic biome beneath it.

But we can't see it, we don't know a lot about it — and we're destroying it.

Human activities like farming, deforestation, overgrazing, and construction all lead to soil erosion. If this were a Marvel movie, we're the supervillain deactivating the force field around the realm. Even farmland protected by no-till techniques still erodes 10 to 20 times as fast as new soil can form.

The UN estimates that restoring land and preventing both biodiversity loss and greenhouse-gas emissions from soil could mean an economic return of more than $125 trillion every year.

Soil-data companies such as the Iowa startup Trace Genomics are trying to help farmers reverse that trend. Trace's executives told Insider they'd raised $56 million since 2015 to provide farmers with data and diagnostics about the biodiversity in their fields.

Building a soil-DNA database

While humans have identified more than 80% of mammals, by one estimate, we may have identified only 0.001% of microbial species. Put another way, there are likely more species of microbes on Earth than stars in the galaxy.

In response to this challenge, Trace specializes in metagenomics, which uses similar technology as a doctor might use to test a patient's stomach microbiome. But instead of sampling the microbes managing our gut health, it aims to sequence the DNA of all the microbes in a soil sample.

Trace Genomics' president, Poornima Parameswaran, has been working with DNA sequencing for nearly two decades. She realized she could use it to fill an information gap in soil health and sustainable agriculture.

"Unless and until you know what's in the soil, how do you know what opportunities exist and how to create products that really foster biodiversity and other soil functions?" Parameswaran said.

Trace has one of the largest agricultural-soil databases in the world. One feature allows Trace to give farmers a score based on the presence of biodiversity, water, nutrients, and carbon in the soil. Based on that score, investors can better judge the soil sustainability of the product grown there.

Trace also uses its data to provide analytics that farmers can use directly. For example, Trace can analyze soil functions like nutrient cycling — even if it doesn't know the name of the microorganisms doing the job.

And it's not just our crops that would benefit from us learning more: Breakthroughs in human medicine such as streptomycin and other antibiotics came from soil fungi and bacteria.

The opportunity to help fight crop diseases led Parameswaran and Diane Wu, her cofounder, to start Trace Genomics in 2015. Both researchers at Stanford at the time, they began walking fields with local berry and lettuce growers. They learned that as bans on chemicals came rolling in, the farmers struggled to find alternatives to effectively treat their fields.

The two researchers first built a lab to diagnose diseases in berries and lettuce. Seven years later, Trace's system can give disease reports for more than 70 different crops.

Providing farmers with data to better manage their fields

Mike Toelle grows soybeans, corn, and alfalfa on his family-owned farm on the border of Minnesota and South Dakota. For the past five years, he's been helping Trace gather data as part of its pilot program.

In that time, Trace's challenge has been to zero in on meaningful diagnostics for farmers.

"Initially, it was almost overwhelming because there's so much information," Toelle said.

Trace's clients, including Toelle, transfer about three samples of the soil from each of their fields into small coffee bags, mark them with a GPS location, and mail them to Trace's lab in Ames, Iowa.

From there, Trace's scientists extract the DNA from the soil and run it through a sequencing machine — a nearly 200-pound device that looks like a tabletop office printer.

After the sequencer runs for 25 to 30 hours, they've generated up to five gigabytes of data that they analyze, upload to their digital platform, and share with the farmer in various forms, such as color-coded maps.

Farmers have historically had access to chemical tests for their soils, which can give information such as the presence of nutrients or a field's acidity. Some companies offer DNA sequencing to test fields for specific diseases. But Trace is one of few companies to analyze the entirety of a field's biology: the billions of microscopic citizens that live in every tablespoon of soil.

Trace's data about the living residents in soil allows it to tell farmers new information about their soil health, such as how well their fields can hold on to crucial nutrients including nitrogen and phosphorus.

Toelle told Insider that Trace's nutrient and disease data had helped him decide how much fertilizer to spread and which crop varieties to plant, as well as where to put them on his fields.

"Every soil is different," Toelle said. "Even within a field, your soils are different, so we really need to understand and get very precise about what we're doing even within a field boundary."

Jason Stegink, an agronomist who serves as a consultant for farmers in western Michigan, is working toward having more than half of his clients use Trace's service.

On one field, a test from Trace confirmed an insight that took him two years to notice without it.

While a traditional chemical test had told him there were plenty of nutrients on the field, he realized his crop was growing unevenly. He needed to add more fertilizer because low microbiological health was preventing the nutrients from being shared throughout the soil.

"The Trace data told us that in one shot," Stegink said.

But Trace's precision comes at a tenfold price. Where a chemical test might run him $20, Trace's test could run him $200.

Still, the cost of DNA sequencing has plunged since the turn of the century. While sequencing a human genome cost more than $100,000 in 2000, current prices are typically less than $1,000.

Helping farmers and developers define sustainability

As farmers try to both increase production and decrease waste, soil insights like those from Trace could help them decide which crops, fertilizers, and chemicals to spread and where.

For example, farmers can combine data from Trace, or similar soil-data companies including Pattern Ag and Biome Makers, with precision agriculture technologies such as autonomous tractors that run on GPS systems.

And to move away from fertilizers, which are finite resources and require massive mining and transportation chains, the agriculture industry can use information from Trace to test eco-friendly alternatives like biologicals. These organic products include microorganisms, insects, and plant extracts that could replace the need for generic fertilizers by regenerating the living network in soil.

With the market for agricultural biologicals projected to reach almost $30 billion by 2029, it's certain that many more eyes will be on the industry than before.

"Trace is one of the pieces that might be able to help not only verify some of those products in their efficacy but also target our integration of some of those products," Stegink said.

Toelle and Stegink agreed that Trace's price and precision would improve over time.

Just as technologies such as microbiome sequencing and probiotics are innovating the way patients are experiencing doctor visits, companies like Trace are working to bring the same tech to soil treatment.

"If we can prescriptively treat things going forward, everything is better," Stegink said. "Our performance is better in the field. Our cost is better. Our environmental impact is better."