Grassroots

Forbes Walker stands in a field of waist-high grass, waving his arms above his head. “This time next year, it will be up to here,” says the soil science professor and UT Extension specialist. This 7-acre plot in rural Henry County in West Tennessee is a demonstration of how native warm-season grasses could solve a myriad of environmental and economic challenges.

The little bluestem, big bluestem and indiangrass planted here show what the land likely looked like long before modern-day uses, when bison and elk roamed North America’s extensive grasslands. Walker and other UT Institute of Agriculture researchers are working together with government, industry and private landowners to restore Eastern grasslands. This back-to-the-future move also is expected to help reduce the nation’s carbon footprint.

Already, Tennessee is at the forefront of sustainable agriculture practices. Just an hour west of here is the UT AgResearch and Education Center at Milan, the world epicenter for no-till farming, a practice which reduces erosion and soil compaction and increases water infiltration. At the 33rd annual Milan No-Till Field Day in July, more than 1,200 farmers, industry representatives and visitors from 11 states and six countries listened to UTIA faculty discuss their latest research in row cropping, soil health, cover crops and even prospects for sustainable aviation fuel.

Walker and other scientists are advocating for even more attention to regenerative agricultural practices. In 2022, UTIA received a $30 million U.S. Department of Agriculture (USDA) grant to encourage farmers and producers to improve Tennessee grasslands, including growing native grasses that will benefit the environment and potentially their own wallets through carbon credits. Researchers and Extension agents are enrolling participants in the nine-state “fescue belt” and setting up monitoring equipment.

Industries are gearing up efforts, too.

Mining for Solutions

In West Tennessee, advanced material company IperionX is planning to extract titanium, zircon and rare earth minerals from the sand beneath the soil. The native grass demonstration plot is part of an effort by IperionX to leave the land better than it was. The plot will be used to study the growth of native grasses, and Walker also will research the use of biochar and gypsum to improve the soil without fertilizers.

Clearly, IperionX has come to the place for resources and knowledge.

“The University of Tennessee is one of most prestigious schools in the state, especially around the topics of agriculture, land and farming,” company officials say.

The company’s Titan Critical Minerals Project covers more than 11,000 acres, with 9,576 acres being leased from individual landowners or groups in Henry, Benton and Carroll counties. Since the 1940s and ’50s, the area known as McNairy Sand has been explored for minerals, but the technology to effectively and efficiently separate the minerals from the sand did not yet exist.

IperionX officials estimate the titanium found here could be used to manufacture about 60,500 Boeing 787 airplanes, and the rare earth metals could be used in the motors of about 24 million electric vehicles. There is potential for huge benefits for residents and the United States, which currently imports these materials from other countries.

Near the demonstration field is a small-scale version of the apparatus for separating the clay and the sand and then the minerals from the sand. Tall metal spiral tubes filter the materials with gravity, with the heavy minerals flowing inward and the sand scattering along the outer side. Scott Sparks, a mining engineer and company co-founder and COO, takes a few handfuls of sand and swishes it around in a pan with water. Eventually, a band of fine black powder forms a line on one side of the pan. “That’s titanium,” he says as Walker looks on.

When extraction gets underway—a timeframe is still to be determined—approximately 98 percent of the sand and soil that was removed for the minerals will be put back into the ground, and then the landowner will decide whether it will be restored or changed to row crops, forest or grassland. The land surrounding the demonstration plot is a mixture of all three, along with areas for hunting fowl and game.

The three kinds of native warm-season grasses were planted here in May. Rain has been plentiful in this part of the state, but these grasses don’t mind dry spells because their roots run deep, as much as 10 feet, pulling in nutrients and moisture. These kinds of grasses suppress weeds, draw pollinators and wildlife like bobwhites that are struggling to find habitat, as well as provide a feast for cattle and other ruminants.

Another benefit would help the planet.

“The potential for carbon sequestration here is enormous,” says Walker, who brings his expertise to an even larger-scale project that promotes a return to more grasslands.

Planting Solutions

Agriculture accounts for 10 percent of greenhouse gas emissions in the U.S., according to the U.S. Environmental Protection Agency. Some of the largest livestock companies and organizations have set lofty goals to reduce carbon or be carbon neutral by 2040 or 2050. The solution is literally under our feet, says Pat Keyser, director of the UT Center for Native Grasslands Management, School of Natural Resources professor and lead for the USDA-funded “Climate-Smart Grasslands—the Root of Agricultural Carbon Markets.” This project grant focuses on the carbon storage potential of grasslands. Like the demonstration plot in Henry County, farms across nine states will test various grassland management strategies.

These native grasses are important because of their vast root systems, which store carbon and are not susceptible to destruction by wildfires like trees are.

Informally, Keyser calls it the “roots project.”

“More roots equal more carbon in the soil, equals more drought tolerance, equals more grass growth above ground. It’s a win-win-win scenario,” he says.

Another potential win for farmers is the burgeoning carbon market and direct contracting with companies that are pledging to reduce their carbon footprint. Many top-tier companies that purchase commodities like soybeans, wheat and beef—including Cargill, JBS Foods and YUM! Brands—pay farmers for implementing carbon beneficial practices. Landowners with IperionX leases also have the potential to get into the carbon market after their land is mitigated.

Aaron Smith, professor of agricultural and resource economics and a UT Extension economist, spoke to farmers this summer at the Milan No-Till Field Day and other UTIA events about the implications for producers who want to participate in carbon markets. While there’s much potential upside, the concept is fairly new and still developing.

“Ensure you can comply with any contract for the entire life of the agreement, and understand what you are being paid to do, whether it’s being paid for storing carbon or being paid for certain production practices,” Smith says. “Price premiums, carbon credit payments or payments for production practices can be earned by signing up with companies to participate in carbon markets.”

In the USDA grasslands project, 100 farms are signed up, and 100 more are in the process. Farmers choose to implement at least three of these strategies: establishing native grasses, improving grazing management, growing legumes instead of using nitrogen fertilizer, growing a field buffer around a crop, establishing silvopasture, or amending pasture soil with biochar or gypsum. Biochar is a charcoal-like product of grass or woody material decomposed at a high temperature in a low-oxygen environment. The work to monitor these strategies will begin next summer. Farmers will receive funding for implementation plus a stipend as they record data on their land.

“Somewhere is the right mix that will move the needle,” Keyser says.

The participating farms are all located in the “fescue belt” of Missouri and Tennessee and parts of Alabama, Arkansas, Indiana, Kentucky, North Carolina, South Carolina and Virginia. These areas used to be covered in native grasses roamed by elk and bison, and, in East Tennessee, routinely burned by Cherokee.

When pioneers settled the lands, they tilled up the grass to grow crops, let their livestock graze them out, or allowed the areas to grow wild, which led to more forested pockets too shady for grass. Beginning in the middle of the last century, farmers planted grasses like tall fescue that were imported and became the dominant type. Non-native tall fescue does not have many of the benefits of native grasses—homeowners experience it if their grass turns brown in the summer drought or if a cool-season field is waterlogged after a hard rain.

What’s Old is Now New

Keyser and Walker point out many of these so-called new strategies are not new at all and have been used in agriculture for centuries, like biochar, which has been used in the Amazon for 2,000 years. Some techniques mimic nature itself.

Walker recalls driving in Middle Tennessee with Keyser after Hurricane Harvey in 2017 brought a deluge of rain to the area. They were visiting beef-cattle farms. The modern, cool-season fescue fields were flooded and impassable. As for the native grass fields, Walker says, “We were driving our truck on them.”