GROUND LEVEL
Examining soil health as a key to successful farming and environmental well-being
By Christopher Outcalt | Photography by Matthew Staver | Sept. 23, 2024
NAVIGATING TOWARD a dropped pin on Google Maps, I exited Interstate 70 in Seibert, Colorado, population 172, about 45 miles shy of the Kansas border. Heading south, I passed the Seibert Travel Stop, a convenience store with a couple of gas pumps out front, a burger joint inside, and a decent stock of souvenir knick-knacks – T-shirts, coffee mugs, key chains. Beyond the travel stop, there’s not much but open fields, wispy grasses, and dead stalks of pale, stubbly grain, remnants of the most recent harvest. The red dot on my phone has me headed another five miles down the road, where I’m meeting a team of Colorado State University soil scientists on a distinctive patch of agricultural land owned and meticulously cared for by a local farmer, Curtis Sayles.
It’s a Thursday morning in early June, and when I arrive in the field, the three-person CSU research team, run by Lauren Hafford, a College of Agricultural Sciences graduate student in the soil and crop sciences department, is huddled around a small pit, preparing to collect samples from the ground. There are two shovels, a ruler, a couple of 5-gallon buckets, and several large plastic bags nearby. After introducing her team of two – recent graduate Eilee Murray and senior Tigist Brunson – Hafford reaches down, scoops up some soil, and gestures for me to hold out my hands. “This is 30 years of soil health,” Hafford says, as she filters the earth into my palms, “and it looks beautiful.”
What makes soil healthy, or “beautiful,” and why that might matter has grown critically important in recent years. Farmers and scientists are grappling with the challenge of producing enough food for a global population that numbers more than 8 billion and is expected to add nearly 2 billion people by 2050, all while farmland is becoming increasingly scarce and a changing climate is tending to make food-growing regions hotter and drier. More and more, scientists have emphasized that soil has a significant role to play in addressing big, urgent agricultural and societal needs – conserving water, improving food production, and combating the effects of climate change. CSU researchers have long been recognized as international leaders in soil science and are continuing to guide efforts aimed at grasping the importance of how soil supports the planet and its vital functions.
Soil research is particularly important against the backdrop of climate change. There is a significant amount of carbon stored in soil, where it functions as an essential building block of nutrient-rich organic matter. Scientists estimate there is more than twice the amount of carbon in soil as there is in the atmosphere. Although the exchange of soil carbon and atmospheric carbon is a natural process, multiple factors, including conventional farming practices, have caused that cycle to become unbalanced, with more carbon going out than coming in. Scientists are now looking for ways to reverse the trend. Making any large-scale progress, however, will require a better understanding of how to measure and manipulate soil carbon on a much smaller scale, say, a field in Eastern Colorado.
Lauren Hafford is a graduate student in CSU’s Department of Soil and Crop Sciences who works closely with Colorado farmers to identify, analyze, and replicate traits of healthy soil.
THERE’S AN EXCITEMENT in Hafford’s voice as she explains what makes this Eastern Plains soil that I’m holding so special. The first thing she mentions is something called “aggregate stability,” a technical term that refers to how well soil maintains its structure. Structure is good, Hafford tells me. It’s a sign of healthy root systems, microorganisms, and other organic matter all harmoniously knotted together underground. There are well-documented upsides to agricultural fields with good aggregate stability – better rain infiltration, better moisture retention, and less susceptibility to erosion. All good benefits when you’re farming with little or no irrigation on Colorado’s Eastern Plains, a part of the state that averages around 17 inches of annual rainfall. (By comparison, some Midwest states regularly receive around 30 or more inches of rain a year.)
There’s a simple way to test aggregate stability: Take some soil and drop it into a glass of water. Healthy soil will remain clumped together. If the soil breaks apart and turns into a brown soupy mess, well, it’s crap. Sayles’ fields withstood a kind of large-scale version of this test the night before Hafford’s team arrived. It had rained for several hours, enough that Hafford thought she might have to reschedule. But when they showed up in the morning, the conditions were fine. “We were worried about a half an inch of rain being too much,” Hafford tells me. “And as you can see, the soil just soaks it in. We’re not standing in 100 acres of mud.”
The next thing Hafford points out is a curled-up earthworm. “He’s just coming out of hibernation, probably because it rained,” she says. “That’s why he’s in a little ball.” Hafford also spots a tiny tunnel, which earthworms create as they burrow through the ground. These worm tunnels naturally aerate the soil and help improve aggregate stability, allowing moisture to seep deeper into the earth and making space for plant roots to take hold. In this case, the tunnel is filled with worm castings, or poop, resembling clumps of pearl couscous. “Absolute gold,” is how Hafford describes worm manure. The castings are rich in nutrients that promote plant growth – phosphorus, calcium, nitrogen, and magnesium. CSU researchers have estimated that earthworms alone contribute to roughly 6.5 percent of global grain production and 2.3 percent of global legume production. To oversimplify, the more worms, the healthier the soil.
Curtis Sayles, who didn’t originally plan to work in agriculture, is constantly experimenting and refining his approach, planting a greater variety of crops and never letting a field lie fallow – two main tenets regenerative agriculture.
Sayles’ soil didn’t always look like this. In fact, he didn’t plan to work in agriculture at all. Although he grew up on a farm in eastern Kansas, Sayles happily went off to college and landed in the oil and gas industry in Houston. He loved the work but never loved the city. When Sayles’ father was looking to expand the family business, which had since relocated to Colorado, Sayles took the opportunity to embrace a quieter life on the Eastern Plains. The idea was to share the work with his two younger brothers, but farming never quite clicked for them like it did for Sayles, so he and his wife eventually took on the operation themselves. He’s been nurturing this blend of earth ever since.
There are numerous variables, but in many ways it started with a decision he made back in 1997 to stop tilling his fields. Some farmers plow their fields in preparation for planting a crop. There are upsides to that process. Among other things, plowing can help eliminate weeds and churn organic matter from the surface into the ground. But it is incredibly disruptive to the soil, ruining any built-up aggregate stability, destroying populations of earthworms and soil microbes, and stripping out other valuable soil organic matter.
When water pools in a field, as above, it is likely a sign the soil does not have the optimal structure, or “aggregate stability,” to hold water efficiently, which is problematic in an increasingly dry climate.
AS NO-TILL has become increasingly common in Eastern Colorado, Sayles has continued to experiment and refine his approach, planting a greater variety of crops and never letting a field lie fallow – two main tenets of an increasingly popular movement known as regenerative agriculture, a land-management philosophy that emphasizes the importance of soil health. Farming this way also saves Sayles money on input costs. He estimates he’s cut his fertilizer bill $100,000 and his chemical bill $50,000. “That is substantial; that’s pure economic value,” Sayles told me. “Since the bottom line is our farm is a business, we have to be profitable.”
After a few minutes huddled around the small pit, Murray and Brunson had measured and bagged the morning’s first samples, collecting soil from two different depths, 0-5 centimeters and 5-15 centimeters. The plan was to continue for the rest of the morning at multiple locations on Sayles’ property. Different iterations of CSU agricultural research teams, overseen by CSU Associate Professor Meagan Schipanski, have been analyzing soil samples from Sayles’ fields for the past seven years, attempting to learn from his farming methods. The way Hafford describes it, they’re trying to help catch the science up to the soil practices that Sayles has been inspired to figure out on his own for almost 30 years. Eventually, she says, new scientific data might help farmers determine which of their soil health practices are having the most beneficial effects or evaluate the potential upsides of adopting a new practice. New data could also help farmers decide which cover crops to plant, when to plant them, and how long to leave them in the ground.
“The soil data we collect now is pretty inadequate to describe the breadth of change that producers like Curtis are seeing,” Hafford says. “We’re trying to find better indicators to help describe those changes and differentiate it from soil where we don’t see that kind of change. It would be wonderful if we could use our data to help support the research that regenerative producers are already doing to foster the health of their soil.”
Soil scientist Meagan Schipanski is an advocate for the health of arid and semiarid lands and has been an invited speaker on the topic for the United Nations.
ON AN OVERCAST day in early December, shortly after lunch, Schipanski settled into a packed conference room in the basement of the United Nations General Assembly Building in midtown Manhattan. The Food and Agriculture Organization of the U.N. had planned a daylong celebration tied to World Soil Day and had invited Schipanski to share her expertise as part of a distinguished panel of international scientists. The panel featured representatives from Columbia University, the University of Saskatchewan, the Soil and Fertilizer Society of Thailand, and the University of Newcastle. After a brief introduction, the moderator looked to Schipanski to kick things off.
The U.N. organizers were interested in Schipanski’s experience researching soil conservation and water supplies and her emphasis on developing good soil health practices in collaboration with innovative farmers. In accepting the offer, Schipanski viewed the panel as an opportunity to represent the semiarid Great Plains, a part of the country she feels is often left out of big conversations about soil and water.
Schipanski began her remarks by framing the stark challenge ahead: Arid and semiarid lands account for about 30 percent of the Earth’s surface; nearly 2.6 billion people worldwide – or about one-third of the world’s population – live in these areas. Unfortunately, these lands are particularly fragile, vulnerable to erosion and degradation. For the past 60 years, irrigation and improved soil conservation practices have helped stabilize these at-risk soils. But there’s a catch. Across the Great Plains, farmers and ranchers have pumped much of that irrigation water from the Ogallala Aquifer, a depleted and increasingly tenuous source of groundwater. What’s more, climate change has exacerbated the problem, making drought longer lasting and more intense. “Water availability drives our ability to improve soil health,” Schipanski told the panel. “How we treat the soil in these water-limited areas is going to make or break whether we have the next Dust Bowl.”
The Homestead Act of 1862 encouraged Americans to put down roots across the semiarid Great Plains and the arid West. These homesteaders brought agriculture along with them, and by the early 1900s were plowing up thousands of acres of protective native grasslands to plant wheat and other crops, transforming the region into “America’s Breadbasket.” In 1931, however, a years-long drought set in. Without enough rain to grow crops and without the shielding of the prairie grasses, the land and soil began to rapidly erode, whipping into massive dust storms that created the Dust Bowl. By 1934, 35 million acres of farmland had been lost, and another 125 million acres were at risk of eroding. The economic fallout was catastrophic; 2.5 million people were displaced, many abandoning land and homes as they headed farther west in search of relief.
Eugene Kelly, a CSU professor and director of the Colorado Agricultural Experiment Station, was recently appointed chair of the U.S. Committee for Soil Sciences. He walks through the Pawnee National Grassland in northeastern Colorado, a site characterized by a native grassland ecosystem that provides important benchmarks for scientific study. “Soil, with its layers of physical and biological materials, is an untapped storyteller of human history,” Kelly says.
THE KEY TO success today, Schipanski says, is to work directly with farmers, giving them more tools to manage this land effectively. “We need more resilient farming systems,” she says. “And these are the practices I see getting us there.” It’s an approach Schipanski has researched for the past three years as a co-principal investigator on the Farmers Advancing Regenerative Management Systems project, or FARMS. Run by the Colorado Conservation Tillage Association, in collaboration with CSU and other partners, the project collected soil samples and analyzed data, including management histories, from 30 farms on the High Plains of Eastern Colorado, Nebraska, and Kansas.
There were a few goals for the project. One was to gather data on the effectiveness of each of the five principles of regenerative agriculture – minimizing disturbance, maximizing soil cover, maximizing living roots, maximizing diversity, and integrating livestock. What the researchers found was that after three years, the best indicator of improved soil health was maximizing living roots – essentially, always having something planted in the ground – an important finding for future discussions about regenerative ag, Schipanski says. “I think there are a lot of generalizations about regenerative farming and about soil health,” Schipanski told me. “I’d like to add more nuance to those conversations.”
Perhaps more important, though, the FARMS project aimed to build a network of farmers who were all interested in improving their soil health management practices. It seemed to work. As part of the final FARMS report, CSU’s Institute for Research in the Social Sciences analyzed the project’s networking benefits. After three years, nearly 60 percent of the producers said that expanding their “friendship network” was the most beneficial aspect of participating in FARMS.
CSU Associate Professor Meagan Schipanski examines microorganisms with field day participants.
Continuing to improve those networks in Eastern Colorado and beyond is a significant part of Hafford’s latest work, a kind of FARMS 2.0 project called Beyond Yield. Hafford describes her approach as “network weaving.” “Curtis, for example, is always trying something new – and he’s doing it on landscape scale,” Hafford told me. “He’s the one creating the change, but it’s not easy. He’s navigating so many unknowns. That’s why a big part of my project is about connecting farmers to each other so they know they’re not in this alone.”
For her part, Schipanski says it is completely understandable if farmers are skeptical of practices that accentuate the importance of healthy soil, particularly because any benefits may not be quickly realized. However, she’s found that farmers, deeply proud of being good land stewards, mostly agree that land with higher concentrations of soil organic matter is more valuable. Instead, Schipanski says, she often finds that the question is not so much whether soil health is worth investing in, but rather who should pay for any short-term costs associated with making that investment.
All of which is why Schipanski sees significant opportunity in learning from and supporting producers such as Sayles, someone who is already finding success focusing on soil health while farming in a semiarid, water-limited environment with no irrigation. “If he can figure out how to do it where he is,” Schipanski says, “it will be relevant to many other parts of the world.”
Near Nunn, Colorado, a field of uncultivated soil, left, lies across the road from cultivated soil, shown in both planted and fallow strips.
WHEN EUGENE KELLY arrived at Colorado State University in the 1980s, first as an undergrad and then as a master’s student studying soil science, people talked about soil a lot differently. Back then, Kelly says, most people thought of soil simply as a medium for plant growth. Over time, though, that thinking has shifted significantly. “The more contemporary definition?” Kelly says. “It’s the ‘skin of the Earth.’ It supports all life functions. It protects us, purifies us. Think of that relative to a ‘medium for plant growth.’ That’s the kind of seismic shift we’ve seen in 40 years.”
The new ways of thinking that sparked this evolution – perspectives that would eventually spread across the country – began circulating around Fort Collins in the 1980s and early 1990s. At first, soil science was mostly agriculture-based, centered on questions related to food production. “We used to call it ‘spread and weigh’ research,” Kelly says. “Spread the fertilizer, weigh the crops. It was all production oriented.” The change happened when agricultural scientists started collaborating with ecologists in CSU’s Natural Resource Ecology Laboratory, or NREL, incorporating soil into ecology.
Those partnerships led to new work on the environmental aspects of agriculture, including the impact that livestock grazing has on soil. What’s more, CSU researchers embraced some approaches not yet widely implemented in ag: incorporating scientific modeling and defining and researching specific systems. “It was just a different way of looking at things,” says Kelly, a CSU professor of pedology since 1989 and director of the Colorado Agricultural Experiment Station, or AES. “The ecologists were using words like ‘resilience’ and ‘sustainability,’ and they were interested in understanding natural processes.”
This was well before climate change would become an essential, all-encompassing subject and the bullseye of so many environmental research targets. Nevertheless, Kelly says, there was a growing acknowledgment at the time that agriculture was having a more significant impact on the planet than previously thought, and there was a desire to better understand how humans were affecting cultivation – the process of tilling a field in preparation for planting a crop. As a graduate student, Kelly studied declining soil fertility across the Great Plains, a region U.S. farmers relied on in the 1980s to become a leading wheat producer worldwide. Kelly’s research compared soil on untouched native rangelands in North Dakota to nearby cultivated fields. What he found was that sites that had been tilled for 30 or 40 years had lost roughly half of their carbon, nutrients, and soil. “That raised eyebrows,” Kelly told me.
In a native grassland setting, Eugene Kelly examines soil profiles and structure, which help reveal the origin and evolution of soil as well as its role in the water cycle.
SOIL CARBON IS especially important because it is considered the best single indicator of healthy soil. It makes the ground more spongelike and feeds critical microbes that produce the nutrients that fuel plant growth. Increased focus on carbon has positioned soil as a fundamental topic in conversations about global climate change, in particular with scientists exploring new ways to put atmospheric carbon back into the ground. “It made soil more scientifically and socially relevant,” Kelly says. “Soil carbon interacts with the atmosphere and oceans, which are impacted by our production and utilization of fossil fuels.” At CSU, the Soil Carbon Solutions Center is bringing together an interdisciplinary team to investigate carbon as a factor in soil health.
The push to measure soil data also spawned the creation of groundbreaking CSU computer models that could simulate long-term changes in soil organic matter. William Parton, a CSU research scientist, guided development of the initial Century model in the late 1980s. Century predicted carbon, nitrogen, and methane exchanges happening in the atmosphere, vegetation, and soil. Parton, University Distinguished Professor Keith Paustian, and others later adapted Century into a daily version called DayCent. In the 2010s, the U.S. Department of Agriculture relied on DayCent to develop COMET-Farm, a web-based tool that estimates soil carbon changes and greenhouse gas emissions happening on lands. The U.S. government also relies on CSU to analyze data for its national greenhouse gas inventory on agricultural land, an accounting that helps track climate goals set in the 2050 Paris Agreement.
“The more contemporary definition of soil? It’s the ‘skin of the earth.’ It supports all life functions. It protects us, purifies us. Think of that relative to a ‘medium for plant growth.’ That’s the kind of seismic shift we’ve seen in 40 years.”
Today, soil is widely acknowledged as a key repository of essential nutrients and carbon, one of the planet’s largest freshwater reservoirs, and an integral component of climate change research and efforts to improve food security. “Everybody is working on soils now,” says Kelly, who was recently appointed chair of the U.S. Committee for Soil Sciences by the National Academies of Sciences, Engineering, and Medicine. Still, there are significant challenges to protecting this resource. According to a recent report by the U.N. Food and Agriculture Organization, 90 percent of the world’s topsoil is at risk of eroding by 2050.
Building on the systems-style approach he adopted years ago, Kelly recently helped secure $1.45 million in federal funding to expand the state’s soil moisture monitoring network, a two-year project designed to help farmers, researchers, water managers, and weather forecasters better understand drought and critical water supplies across Colorado. Kelly is also looking for ways to incorporate artificial intelligence into soil research and education. “We need people like Meagan Schipanski who are doing great work with farmers, and then we also need people to look even further ahead,” Kelly says. “What’s this all going to look like in another 20 to 30 years?”
Professor Kelly Wrighton (on far right in the left photo and on left in the right photo) works with researchers in the field to sample soils so their microbiomes may be examined for indicators of health. Photography: Alex Wettengel and Jorge Villa.
Professor Kelly Wrighton (on far right in the top photo and on left in the bottom photo) works with researchers in the field to sample soils so their microbiomes may be examined for indicators of health. Photography: Alex Wettengel and Jorge Villa.
One answer might have to do with microorganisms. CSU’s Kelly Wrighton, a professor in the Department of Soil and Crop Sciences, specializes in researching microbiomes, collections of organisms that exist in a particular environment. Much of Wrighton’s research explores the soil microbiome, a system that scientists believe has the potential to more quickly and accurately predict changes in soil organic matter. “A lot of the indicators we have for soils take a long time to change,” Wrighton says. “These microbes are the canaries in the coal mine. Earlier detection of long-term patterns – that’s the promise of the microbiome.”
Wrighton is encouraged by initial results from an experiment at CSU’s Agricultural Research, Development and Education Center in Fort Collins. Collaborating with Kelly and AES Associate Director Troy Bauder, Wrighton searched for microbial clues in 10 years of data comparing agricultural fields that had been transitioned to no-till against fields that hadn’t. “The microbes were screaming in terms of their response,” says Kelly, explaining that the fields that hadn’t been plowed showed significantly more microbial activity. “I couldn’t believe it.” Wrighton has since expanded her work, searching for similar data on hundreds of sites across the state.
Schipanski sees significant promise in what Wrighton is learning. “Kelly and I have talked a lot about how all the soil health tests we use are really rudimentary methods for what she does,” Schipanski told me. “The detail she has and what we can tell farmers – it’s a huge gap. We’re not there yet, but we’re trying to fill it.”
“I call it ‘opportunistic cropping,’ or opp crop for short. I have a crop rotation; however, if I have an opportunity to do something else, I’m not going to sit on my thumbs.”
AFTER SPENDING THE morning collecting soil samples on Sayles’ property, Hafford, Murray, and Brunson drove 20 minutes up the road to meet with another regenerative dryland farmer, Stuart McFarland. Like Sayles, McFarland had participated in the FARMS project and agreed to continue with Hafford’s Beyond Yield work. When the CSU team pulled into McFarland’s driveway, Hafford hopped out of the pickup and greeted him with a hug.
McFarland embraced some of the tenets of regenerative ag early in his farming career. He sold his plow and went all in on no-till. He questioned the wisdom behind strict crop rotations and long fallow periods. McFarland eventually realized that what he most subscribed to was an ability to be flexible and nimble, to try to make the most of the weather on any given day or week. “I call it ‘opportunistic cropping,’ or opp crop for short,” says McFarland, who earned his undergraduate degree in wildlife biology at CSU. “I have a crop rotation; however, if I have an opportunity to do something else, I’m not going to sit on my thumbs.” This approach, he says, allows him to grow more diverse crops and maximize the amount of time he has living roots in the ground.
That day in early June, while Hafford and her team were out collecting samples, McFarland showed me an example of this philosophy. We drove to a field a few minutes north of his house and parked off the side of the dirt road. McFarland explained that he’d been getting ready to fallow this field after last year’s harvest. Problem was, it kept raining, making it difficult to prepare the land. Frustrated trying to battle the weather, McFarland decided instead to embrace it. “Every time I see rain fall on a field that doesn’t have anything in it,” McFarland says, “I think, ‘Welp, there goes that.’”
During a field day in Seibert, Colorado, farmer Doug Steffen, left, gets help building compost, an example of the soil amendments he uses on a large scale. Participants, top right, make compost extract, and, with CSU scientist Lauren Hafford, bottom right, examine compost microorganisms under a microscope.
During a field day in Seibert, Colorado, farmer Doug Steffen, top, gets help building compost, an example of the soil amendments he uses on a large scale. Participants, middle, make compost extract, and, with CSU scientist Lauren Hafford, bottom, examine compost microorganisms under a microscope.
It was late in the season, but he still had time to plant proso millet – a cereal grain that grows well in warm, water-limited areas. Now, McFarland had a crop to harvest. What’s more, the soil had benefited from months of nourishing plant growth. And there was another moral to this story, McFarland told me. When he began to embrace opp crop, he says, “Things just got really fun.”
Schipanski views the kind of flexibility that McFarland and Sayles have each adopted in their own ways – an openness to experimentation and to growing a greater variety of crops – as critical to the future of agriculture in Eastern Colorado, across the Great Plains, and in other parts of the world. “That’s one of the things I love about working with farmers,” Schipanski says. “Their personalities shape how they do things.”
Schipanski’s vision is to build more adaptable farming systems, and the benefit of collaborating with producers such as McFarland and Sayles, she says, is that they are the ones who are expanding the boundaries of what’s possible on big landscapes. “We need to have less of a commodity-centric and more of a whole systems view of agriculture – in terms of our policies, markets, and infrastructure. We’re not going to change everything. But I do think if we have soil health as the cornerstone of what guides our management of these different systems – that’s a pretty good place to be.”
Photo at top: Stuart McFarland, a CSU alumnus and dryland farmer on the Eastern Plains of Colorado, checks a field of sunflowers in early August. McFarland collaborates with Colorado State University soil scientists to share information about building soil health for improved crop production.
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