Greenhouse Gas Scientist Questions How To Cut Emissions On Her Own Farm

May 20, 2019

Researchers and advocates have billed agricultural soil management as a powerful tool to capture and sequester carbon from the atmosphere and counteract global climate change. A coalition of international scientists has said the world must take drastic action in the coming years to avoid the worst impacts of climate change, steps that will rely on key industries like agriculture. But on one farm in central Iowa, a scientist’s greenhouse gas research is leading to tough questions about how to manage her own land.

Kevin and Ranae Dietzel’s dairy farm in central Iowa’s Hamilton County is not your average operation, in a state known for its incredible scale of corn and soybeans production. Reaching their 80 acre dairy farm on an early spring morning this April means driving past vast open stretches of bare earth warming in the sun, conventional corn and bean farms that largely haven’t had living roots in the ground since last year’s crop. In this area there aren’t many fences to speak of; livestock have been largely taken off the land in recent decades, and corralled by the hundreds or thousands in feedlots or long, narrow barns.  

But on the Dietzels’s Lost Lake Farm, there are just a handful of animals. Kevin points out a particularly friendly cow, and a newborn calf, gangly on too-tall legs.

“This is Ola. And this is Basa! The first, and so far only calf of the year,” Kevin says.

The Dietzels didn’t want to run a large-scale operation, and say they couldn’t afford it if they wanted to. It was hard enough to pull together their farm as it is now: as of this April they had a core herd of 14 milking cows, 5 heifers and 8 yearling heifers on about 80 acres. The Dietzels turn their milk into artisan cheese and sell it directly to customers at farmers’ markets and grocery stores, sidestepping a notoriously volatile milk market. In an area where farms often run 1,000 acres or more, the Dietzels’ approach is almost unheard of.

"I feel like we're helping with the ecosystem and wildlife and so forth in a lot of ways that if we had cropland we would not be [...] there are just so many things that fit with us philosophically with this type of system." - Kevin Dietzel, Lost Lake Farm

In a landscape defined by two annual crops, the Dietzels grow a mix of perennial grasses and legumes, without the use of synthetic fertilizers or pesticides, instead relying on compost. They’ve reduced their tillage and they rotationally graze their grass-fed cows.

“So for us that means moving them to a new piece of grass twice a day. And so that helps with distributing those nutrients,” Kevin said. “It’s better for the soil because all that stuff that’s getting trampled will get incorporated.”

Cows move across the land like wild elk and bison used to, before Iowa’s vast native prairie was plowed under, steadily grazing and moving on, stamping down plant matter and mixing in their manure as they go. This process promotes plant growth and nourishes the soil, helping fuel the bacteria, fungi and insects that maintain the rich, dark earth Iowa is famous for.

Looking out over the rolling hills of this farm, there are groves of bur oak, hackberry, ash and elm trees, a small winding creek the cows love to poke around in. On many conventional farms, these areas would be considered unproductive, the trees a nuisance, the waterways in need of artificial drainage called tiling. On the Dietzels’ farm there are tree swallows and frogs, signs of biodiversity and a healthier ecosystem.

“Where the green ends is where our property ends,” Kevin said, laughing. Looking out over the rolling hills, another farmer is at work applying synthetic fertilizer to a neighboring field, the engine whirring in the distance.

“I feel like we’re helping with the ecosystem and wildlife and so forth in a lot of ways that if we had cropland we would not be,” Kevin said. “There are just so many things that fit with us philosophically with this type of system.”

The name of the land itself, Lost Lake Farm, is an homage to Iowa before European settlement. The Dietzels’ land lies on the shores of what was Lake Cairo, once a massive lake on the prairie, that farmers deemed an obstacle and drained away by installing a system of underground tile lines.

"Where the green ends is where our property ends." - Kevin Dietzel, Lost Lake Farm

Ranae and Kevin returned to Hamilton County to raise their two young kids and start their farm, in part because they’re passionate about creating a viable future in a rural community. Both of their families have been farming in the Upper Midwest going back multiple generations. But they set up their farm the way they did in part because they’re deeply concerned about climate change.

Off the farm, Ranae is a soil scientist working on her post-doctorate research at Iowa State University, where she focuses on greenhouse gas emissions. For her Ph.D., she looked at adding carbon to the soil, comparing outcomes across systems of prairie and corn. She’s painfully aware of how agricultural emissions fuel the world’s climate change problem, and how farmers are situated in the crosshairs of the damaging effects that follow.  

“I went into it being like, specifically because I thought, ok I want to help with agriculture’s big contribution to this greenhouse gas problem,” Ranae said.

Agriculture accounts for about 10 percent of the country’s emissions, particularly from soil, livestock and manure management, which can release nitrous oxide and methane, greenhouse gases that are many times more powerful than carbon dioxide.

When Dietzel got into the field, she said researchers were really excited about soil carbon sequestration. Some have gone so far as to posit the practice could “save the earth”. The world’s soils hold an immense amount of carbon – three times the amount in the atmosphere, according to some analyses. Capitalizing on the earth’s ability to retain carbon could have far-reaching effects for greenhouse gas mitigation, advocates say.

"I was like, this is so exciting, we could plant all these cover crops and this could just like totally save us and I was so excited [...]and then when I got into it I personally started feeling like, I don't know about this." Ranae Dietzel, soil scientist, Iowa State University

Through the natural process of photosynthesis, plants pull carbon dioxide out of the air, and sink it into the soil, where it fuels a vast web of microbes. These microbes break down organic matter that plants need to grow, retaining some carbon in the soil, and also releasing some carbon dioxide back into the atmosphere.  

A slate of practices are thought to boost carbon levels in the soil, including planting cover crops, counteracting erosion, reducing tillage and limiting the use of synthetic fertilizers. If enough farmers took these steps on a global scale, vast amounts of greenhouse gases could be pumped into the soil, Dietzel thought.

“I was like, this is so exciting, we could plant all these cover crops and this could just like totally save us, and I was so excited,” Ranae said. “And then when I got into it I personally started feeling like, I don’t know about this.”

In the years since Dietzel got into the field, some scientists have grown more skeptical of the potential of soil carbon sequestration. Subsequent research has found that the soil’s capacity to store carbon has been greatly overestimated, and rising temperatures could induce microbes to release more carbon dioxide than previously thought, turning the world’s soils into a net carbon source, instead of a sink.

"That's what I worry about, just the false sense of security I think can be really strong because everybody wants that sense of security, right? And everybody wants to be reassured." - Ranae Dietzel, soil scientist, Iowa State University

A host of questions and uncertainties remain. But based on her own research and the analysis of others in the field, Ranae says soil carbon storage is not the silver bullet she thought it was, despite the attention from researchers, advocates and policymakers.

“That’s what I worry about, just the false sense of security I think can be really strong because everybody wants that sense of security, right? And everybody wants to be reassured. And it sounds so simple, so why not do it?”  

Dietzel says the bulk of agriculture’s greenhouse gas emissions stem from land conversion; the greatest damage was done when farmers first plowed the vast expanse of prairie, draining marshes, wetlands and lakes.

Ranae’s research and scrutiny of soil’s ability to sequester carbon long-term has led to some difficult questions on Lost Lake Farm, spurring the Dietzels to wonder if their conservation practices are a net carbon sink, or whether they should invest in other ways to trap carbon and cut emissions.

So far, Kevin and Ranae are striving to keep their farm diverse: they’re maintaining living roots in the ground nearly year-round, curbing erosion and runoff; they’re cutting out carbon-intensive synthetic inputs like pesticides and fertilizers and they rarely rely on diesel engines (Kevin generally covers the 80 acres on foot). These practices keep them more resilient in changing weather and better able to handle stretches of drought and pounding rains, even if some of those same practices could mean boosting microbial communities that could release more greenhouse gas emissions in the long-term.

“All of these practices, there are really good things that come out of them. It just may not be greenhouse gas mitigation,” Ranae said.

Even with Ranae’s intimate knowledge of ag emissions, Kevin says he struggles to see what more he could do on their farm.

“I think we think more about the being adaptable to climate change than our impact,” Kevin said. “Not that I don’t think about it, but I feel like there’s only so much I can do there.”

"Everybody needs to remember the basic economics [...] Decisions were made that got us to where we are today, so decisions can be made to take us in a different direction." - Mike Duffy, emeritus economics professor, Iowa State University

Ultimately many of their decisions come down to, how will they pay their bills? So far they haven’t invested in renewable energy sources like wind or solar that they suspect could do considerably more to offset emissions on their farm. Mike Duffy is an emeritus economics professor at Iowa State University and says finances are the guiding reality for many farmers.

“Everybody needs to remember the basic economics,” Duffy says.

Federal programs support larger, conventional farms, which generally rely heavily on fossil fuels, for synthetic fertilizers and pesticides, a fleet of farm vehicles with diesel engines and a dependency on international freight and trade networks to ultimately get their products to consumers.

Duffy says these farmers aren’t necessarily feeling the cost of their emissions. To have different outcomes we need to change behavior and change incentives to encourage conservation practices and diversification, he says, and that could mean huge investments from the public and private sector, and changes to federal farm policies as we know them.

“Decisions were made that got us to where we are today, so decisions can be made to take us in a different direction,” Duffy says.

This kind of buy-in from the public, and the sweeping investments from governments and corporate interests and the coordination to get it all done, is not unheard of, says University of Iowa environmental economist Silvia Secchi. The country fought World War II, made it to the moon, and eradicated polio. But if the United States is going to take the steps to promote sustainable agriculture at scale, public consensus is vital, she says.

“It’s not totally pie in the sky, Secchi said. “It’s more like, do we want to do more of the same, or do we want to put in an effort to change things?”

Without structural changes to federal crop insurance programs and subsidies for preferred products, it’s not clear how many farmers can fight the economic tide and do what the Dietzels are doing – wrestling with the challenges of regenerative ag and climate change, while raising their young kids in rural Iowa. And unless more farmers can make a living in rural farming communities, it’s not clear who all will be there to help mitigate climate change, imperfect and uncertain as some of the solutions are.

“We just can’t abandon these areas, right?” Ranae said. “So it’s better to try and keep these stronger places but it’s hard to stay here unless you come up with your own way to do it.”

This story is part of a collaboration among 14 newsrooms in the Midwest and coordinated by Inside Climate News.  Follow this link to read other stories in this series, titled "Middle America's Low-Hanging Carbon."