This Ancient Practice Could Help Revitalize America’s Corn Belt

This story was originally published by Yale Environment 360 and is reproduced here as part of the Climate Desk collaboration.

Drive through rural Minnesota in high summer and you’ll take in a view that dominates nearly the entire US Midwest: an emerald sea of ripening corn and soybeans. But on a small operation called Salvatierra, 40 minutes south of Minneapolis, Reginaldo Haslett-Marroquin is trying something different. When he bought the land in 2020, this 18-acre patch had been devoted for decades to the region’s most prevalent crops. The soil was so depleted, Haslett-Marroquin says, he thought of it as a “corn and soybean desert.” Soon after, he applied 13 tons of compost, sowed a mix of prairie grasses and rye, and planted 8,200 hazelnut saplings.

While he won’t reap a nut harvest until 2025, the farmer and Guatemalan immigrant doesn’t have to wait to make money from the land. He also runs flocks of chickens in narrow grassy paddocks between the rows of the fledging trees, where they hunt for insects and also munch on feed made from organic corn and soybeans, which they transform into manure that fertilizes the trees and forage.

Salvatierra is the latest addition to Tree-Range Farms, a cooperative network of 19 poultry farms cofounded in 2022 by Haslett-Marroquin. Chickens evolved from birds known as junglefowl in the forests of South Asia, he notes, and the co-op’s goal is to conjure that jungle-like habitat. Chickens crave shade and fear open spaces; trees shelter them from weather and hide them from predators. In 2021, Haslett-Marroquin’s nonprofit, Regenerative Agriculture Alliance, purchased a poultry slaughterhouse just south of the Minnesota border in Stacyville, Iowa, where farms in the Tree-Range network process their birds. You can find the meat in natural-food stores from the Twin Cities area to northern Iowa.

By combining food-bearing trees and shrubs with poultry production, Haslett-Marroquin and his peers are practicing what is known as agroforestry—an ancient practice that intertwines annual and perennial agriculture. Other forms include alley cropping, in which annual crops including grains, legumes, and vegetables grow between rows of food-bearing trees, and silvopasture, which features cattle munching grass between the rows.

“With just a couple feet of soil standing between prosperity and desolation, civilizations that plow through their soil vanish.”

Agroforestry was largely abandoned in the United States after the nation’s westward expansion in the 19th century. In the 2022 Agricultural Census, just 1.7 percent of US farmers reported integrating trees into crop and livestock operations. But it’s widely practiced across the globe, particularly in Southeast Asia and Central and South America. According to the UN Food and Agriculture Organization, 43 percent of all agricultural land globally includes agroforestry features.

Bringing trees to the region now known as the Corn Belt, known for its industrial-scale agriculture and largely devoid of perennial crops, might seem like the height of folly. On closer inspection, however, agroforestry systems like Haslett-Marroquin’s might be a crucial strategy for both preserving and revitalizing one of the globe’s most important farming regions. And while the corn-soybean duopoly that holds sway in the US heartland produces mainly feed for livestock and ethanol, agroforestry can deliver a broader variety of nutrient-dense foods, like nuts and fruit, even as it diversifies farmer income away from the volatile global livestock-feed market. In recognition of this potential, the US Department of Agriculture (USDA), in late 2022, launched a $60 million grant program to help farmers adopt such practices.

For decades, Midwestern farmers have devoted tens of millions of acres to just two crops, leaving the ground largely unprotected from wind and rain between harvest and planting. As a result, the loamy trove of topsoil that settlers found there has been pillaged. Using satellite imagery, a team of University of Massachusetts researchers has calculated that a third of the land in the present-day Corn Belt has completely lost its layer of carbon-rich soil. And what’s left is washing away at least 25 times faster than it naturally replenishes. As prime topsoil vanishes, farmers become more dependent on fertilizers derived from fossil fuel.

Not surprisingly, given those applications, the Corn Belt is also in the midst of a burgeoning water-pollution crisis, as agrichemicals and manure from crowded livestock confinements leach away from farm fields and into streams and aquifers. In other words, our breadbasket is a basket case. As University of Washington geomorphologist David Montgomery noted in his magisterial 2007 book Dirt: The Erosion of Civilizations, “With just a couple feet of soil standing between prosperity and desolation, civilizations that plow through their soil vanish.”

These practices remain rare, in part because they are marginalized by federal farm policies that reward maximizing the production of corn and soybeans.

Breaking up the corn and soybean rotation with trees—and freeing some farm animals from vast indoor facilities to roam between rows, where their manure can be taken up by crops—could go a long way to addressing these crises, experts say. Trees actually have a much longer and more robust history in the Midwestern landscape than do annual crops. Think of the Midwestern countryside before US settlers arrived, and you might picture lush grasses and flowers swaying in the wind. That vision is largely accurate, but it’s incomplete. Amid the tall-grass prairies and wetlands, oak trees once dotted landscapes from the shores of Lake Michigan through swathes of present-day Indiana, Illinois, Iowa, and Missouri, clear down to the Mexican border. These trees didn’t clump together in dense forests with closed canopies but rather in what ecologists call savannas—patches of grassland interspersed with oaks. Within these oak savannas, which were interlaced with prairies, tree crowns covered between 10 percent and 30 percent of the ground. They were essentially a transition between the tight deciduous forests of the East and the fully open grasslands further west.

And in the region where Haslett-Marroquin farms—part of the so-called Driftless Area, which was never glaciated—trees proliferated even more intensely. In pre-settlement times, according to a 2014 analysis coauthored by Iowa State University ecologist Lisa Schulte Moore, closed-canopy forests of oaks, sugar maples, and other species covered 15.3 percent of the area, and woodlands (low-density forests) took up another 8.6 percent. Prairies—the ecosystem we readily imagine—composed just 6.9 percent. Oak savannas made up the rest.

In the Driftless and in the rest of the Midwest, Native Americans played an active role in managing savannas, prairies, and forests, where they harvested nutrient-dense acorns for food and other uses. Everything began to change in the mid-19th century, when settlers evicted or killed most of the original inhabitants, drained wetlands, razed trees for lumber, and ripped into the land with plows. In place of staggering biodiversity, an agricultural empire of row crops arose, tended with the tools of modern engineering and industry: genetically modified seeds, insect- and weed-killing chemicals, synthetic and mined fertilizers, and massive tractors and combines. Oak savannas, meanwhile, have been vanishing from the landscape. Today, they occupy a mere 0.02 percent of their historic Midwestern range.

For most of the past century, any push to return trees to the Corn Belt centered on ecosystem services, not food production. Planting trees along streams and rivers—creating what’s known as riparian buffers—helps filter agrichemical runoff and improve water quality. Then there are “wind breaks,” stands of trees strategically placed to shelter crops from wind.

But these practices remain rare, in part because they are marginalized by federal farm policies that reward maximizing the production of corn and soybeans, with subsidized crop insurance and price supports, and disincentivize planting alternative crops.

Trees could play a much bigger role and, once established, could more than pay their way by delivering cash crops. A 2018 paper by University of Illinois researchers found that black walnut trees placed in rows between fields of corn and soybeans (alley cropping) would deliver more profits to landowners than field-crop-only farming on nearly a quarter of the Corn Belt’s land.

Haslett-Marroquin and his fellow poultry farmers aren’t the only ones hoping to reimagine agriculture in the Corn Belt by reinstating the role of trees. The Savanna Institute, founded in 2013 by a group of farmers and academic researchers at a gathering in Illinois, promotes agroforestry in the region. Its funders include the USDA and other government agencies, environmental foundations, and business interests including Patagonia and the family behind Clif Bar. In addition to operating demonstration farms in Illinois, Indiana, and Michigan, run in partnership with landowners, the Institute trains and places apprentices on farms that mix trees with crops or livestock. At the 250-acre Hawkeye Buffalo & Cattle Ranch in northeast Iowa, for example, the McFarland family sells grass-fed beef and bison meat from animals raised on restored oak savanna. The other “apprenticeship” farms are smaller operations.

Fred Iutzi, the institute’s director of agroforestry innovation, says an arboreal revival throughout the region would make it more resilient to climate change. Tree canopies buffer soil from the impact of heavy rain, and their roots plunge deep beneath the soil surface and fan out laterally, further holding soil in place. They suck up nutrients all year long, keeping excess fertilizer and manure from leaching away and polluting water. Trees shield crops and soil from the wind. And they both build carbon in the soil as their leaves drop and decompose and store it in their roots, trunks, and branches. Altogether, Iutzi says, an acre of land under agroforestry can sequester five metric tons of carbon dioxide annually, versus about one ton for an acre of corn or soybeans under optimal conditions, which include reducing tillage and planting off-season cover crops.

“There’s a ton of momentum; there’s a historic amount of resources and opportunities for folks to get into it.”

While practices like alley cropping and silvopasture are eligible for support from USDA conservation programs, they haven’t been widely adopted. A recent study co-authored by Trent Ford, the Illinois state climatologist, found that between 2017 and 2023, the USDA’s Environmental Quality Incentives Program doled out just $900,000 to support agroforestry practices in the Corn Belt, a sliver of its overall budget.

But more money is on the way. In 2022, as part of its $3.1 billion Partnership for Climate Smart Commodities program, the USDA announced a $60-million five-year effort to expand agroforestry production and markets in the central and eastern regions of the United States, plus Hawaii. Managed by The Nature Conversancy in partnership with the Savanna Institute and other groups, the project’s goal is 30,000 new acres of agroforestry by 2026, says TNC’s Audrey Epp Schmidt, who leads the project. So far, 35 projects have been selected for funding, eight in the Corn Belt.

For now, an agroforestry renaissance remains at a nascent phase, Epp Schmidt says, “but there’s a ton of momentum, there’s a historic amount of resources and opportunities for folks to get into it.” What the movement needs, she says, is a farmer-to-farmer network: “That’s really when this is going to take off—when farmers see the success of their neighbor’s [agroforestry] operations.”

Even so, the Corn Belt will be a tough nut to crack, says Silvia Secchi, a natural resource economist at the University of Iowa. Such expenditures, while important, will struggle to overcome the formidable inertia of corn and soybeans. The proximate reason is the subsidies that keep the region’s farmers afloat even as their soil washes away. But ultimately, she says, farmers in the region “strive to be as simple as possible and as mechanized as possible”—a mindset that favors focusing on two cash crops instead of a more complex, labor-intensive approach, like agroforestry.

Yet Iutzi remains hopeful. In the 1920s, he says, the idea of a federal farm policy centered on soil conservation seemed beyond the realm of possibility. Then came the Dust Bowl, a severe soil-erosion crisis that triggered New Deal legislation that, for a time, tempered overproduction of farm commodities and held soil in place.

It’s impossible to say precisely what type of event would force policymakers and farmers to drastically change course in the Corn Belt. But as the region’s vast corn and soybean operations continue hemorrhaging soil and fouling water and climate change proceeds apace, they may find themselves looking for new directions sooner than later. Iutzi thinks projects like Tree Range Farms could show the way forward. “History is just absolutely peppered with this pattern of big disruptions of one kind or another being the catalyst for big change,” he says. “And it’s ideas that are really well honed, when the time comes, that really surge.”