Saltwater intrusion leads farmers near Chesapeake Bay to ponder ‘switch’

As winter turned to spring, Wendell Meekins planted his corn crop and prepared for the stalks to shoot up tall and green, just as they always had. That didn’t happen.

“The corn got up about maybe 2 inches tall, turned yellow and just died completely,” the veteran farmer said as he tromped through the muddy field on Maryland’s Eastern Shore nearly a year later. “No fodder at all was left of it. So, it doesn’t even look like it’s been planted.”

The field lies within a couple hundred yards of the Little Choptank River, a Chesapeake Bay tributary that flows through this low-lying section of Dorchester County. During unusually high tides, saltwater backs up into the ditches and spills across the land.

Even in relatively low doses, salt is lethal to the crops that are typically grown on the Delmarva Peninsula — the corn, soybeans and wheat that become fodder for the region’s $5 billion chicken industry. An expanding raft of research suggests that climate change is putting more farmers’ livelihoods at risk here as higher seas and widespread storm surges become the norm.

Meekins walked on. At the far edge of the field, he found his way obstructed by a chest-high thicket of grass-like shrubs. They were yellow from their winter dormancy but otherwise seemed to be thriving in their saline environment.

“These are the remnants of a switchgrass crop that was planted here probably in 2014 or 2015 that have come back and reseeded after we tried to take it out,” he said. “So, the switchgrass actually is working here.”

Could it work on other farms impacted by saltwater intrusion? And if so, would there be a market for it?

For many coastal farms, the answers to those questions will go a long way toward determining whether they can stay above water financially in the coming decades, even as their land literally goes underwater. There are serious implications for the Bay’s health as well.

Plan in motion

Switchgrass (Panicum virgatum) has the potential to help with both issues, said Jarrod Miller, a soil expert and agricultural consultant with the University of Delaware. He’s part of a multi-university team of researchers that is racing to develop salt-tolerant crops for farmers losing land to saltwater intrusion.

“Most of these grain crops aren’t adapted to salinity. You can already see the salt land is lost,” he said. “So, this part of the project is looking at a replacement, something you can plant there that’s going to last longer and give opportunities to maintain the field [in crop production].”

The University of Maryland Eastern Shore (UMES) is the lead recipient of a $5 million grant from the U.S. Department of Agriculture to conduct a five-year pilot project looking into whether switchgrass can be marketed as a feedstock for biofuel production.

Researchers have recruited about a dozen Eastern Shore farmers so far, mainly in Somerset County, to plant the seeds this spring on test plots. The effort, dubbed the Alternative Crops and Renewable Energy (ACRE) project, is also testing the viability of using standard cover crops, such as rye grass, as an alternative in salt-impacted areas.

But the central aim is to promote switchgrass. Farmers who choose to plant and harvest it are receiving $400 per acre while those who opt for cover crops are getting $150 per acre.

One reason for pushing switchgrass is that it tolerates salt better than just about any other potential commodity, said Kate Tully, a University of Maryland agroecologist who is part of the effort. She has authored or co-authored several studies about Delmarva’s saltwater intrusion in the last five years.

Switchgrass is a native to the Chesapeake Bay region and grows in abundance along tidal waters. Further, the scientists say, it has several potential marketable uses, including as filler material for erosion-control mechanisms, poultry bedding and natural camouflage for hunting blinds.

Still, as of the 2022 USDA agricultural census, just 58 farms nationwide reported a switchgrass harvest. Among Bay states, Pennsylvania claimed 20 of those farms, New York had five and Virginia had two. There were none in Maryland.

The ACRE researchers believe the best hope for turning a profit on the Eastern Shore lies in combining the plant’s carbon-rich shoots with nitrogen-laden poultry manure to create a well-balanced fuel source for anaerobic digesters that help produce energy. Switchgrass can grow 6 feet tall or higher, ensuring plenty of fuel for a hungry digester.

“It’s not a corn, but can we create a market,” Tully said. She added that another attribute in switchgrass’s favor is that, unlike corn, employing the crop in the energy sector wouldn’t interfere with the global food supply. (Humans don’t eat switchgrass.)

Anaerobic digesters use bacteria to break down organic waste to produce biofuel. The technology is far from new. It’s commonly used at landfills to divert food scraps and grass clippings from the waste stream. But it’s less proven with using poultry droppings as its main fuel.

A digester owned by Chesapeake Utilities near Pocomoke City, on Maryland’s Lower Eastern Shore has been tapped to do the job.

The ACRE project could have several benefits beyond offering farmers a paycheck, said Jonathan Cumming, the UMES plant professor leading the study. He frames the effort as a means of removing carbon from the atmosphere while producing renewable energy.

Like all plants, switchgrass absorbs carbon from the air through photosynthesis and stores it in its tissues. Then, the digester converts that carbon into fuel — and, in turn, energy. “We’re actually fighting climate change,” he said.

The state of Maryland has been helping to offset the Pocomoke digester’s costs since it began operation in 2017, totaling more than $1.5 million. Energy and agricultural regulators have long hoped that it and similar projects can be scaled up to provide an alternative destination for the region’s chicken waste. In addition to the biofuel, the digestion process yields a nutrient-rich byproduct that can be used to improve a farm’s soil.

Alison Schulenburg, who is writing up the research as part of her doctoral dissertation at the University of Maryland College Park, is installing sensors at participating farms and on the Chesapeake Utilities digester to measure the greenhouse gas emissions involved in the process.

“I think it’s promising,” she said. “I’m hoping there are other benefits beyond just using it in the anaerobic digestion.”

Threat to the Bay

If all goes according to plan, local water quality could be another beneficiary — because, unlike other crops, switchgrass can withstand salt enough to survive and do what plants do: absorb nutrients from the soil.

That could be a game changer in the region, researchers say. For several decades, farms spread more manure than their crops and the soil could hold. When it rains, those excess “legacy” nutrients get washed into nearby waterways and into the Bay, triggering algae blooms that upend the aquatic ecosystem. The expert consensus is that nutrient pollution from agricultural pollution is one of the biggest and hardest-to-address threats to the Bay’s health.

Saltwater intrusion complicates the problem, Tully explained. Under normal conditions, the phosphorus in manure clings to iron molecules in the soil. When water covers the soil, resulting in a low-oxygen environment, the iron tends to eject the phosphorus particles.

When the inundation is freshwater like rainfall, it’s only a temporary problem, Tully said — because the phosphorus can simply rebind with the iron once the water drains away.

But saltwater is another story, she said. Its sulphate tends to stick to the iron in the same spot where the phosphorus had been, permanently evicting it from the soil and setting it loose in the environment.

“It’s kind of like musical chairs,” Tully said. “The phosphorus is now bumped off, and it’s hanging out in the water.” From there, the receding tide can carry the phosphorus into nearby waters, upsetting their fragile nutrient balance.

It’s unknown how much of a role saltwater intrusion plays in harming the Bay’s health this way. But Tully suspects at the very least that local streams suffer from the deluge of excess phosphorus.

Saltwater takes over

What is known is that the amount of salt-impacted farmland is approaching epidemic levels on the Eastern Shore.

The Bay is bordered by land on three sides. But saltwater intrusion has been almost entirely confined to its eastern shoreline because the elevation of the Delmarva Peninsula is low, even well inland. During the Colonial era, farms sprang up near the water to ease the transport of commodities across great distances. And many have remained there due to the relative lack of development pressure.

But after centuries of cultivation, this land is under increasing threat of being swallowed up by the Bay. Climate change has caused the Bay to rise about a foot over the past century — about twice as fast as the worldwide average, studies suggest. And up to 5 feet of additional rise is possible by 2100, according to the University of Maryland Center for Environmental Science.

Tully and her fellow researchers have been working to quantify the region’s growing salt problem. Aided by satellite imagery, they reported in 2023 that about 2,200 acres of farmland on the peninsula had converted to salt patches and another 20,000 acres had turned into marsh.

There aren’t many government programs available to help farmers grapple with the financial blow from losing land to salt, experts say. The same 2023 study estimated that farmers’ saltwater-related economic losses topped $100 million in the region in 2016-2017 alone.

“Change is coming, and we have to deal with this,” said Cumming, the UMES researcher.

Schulenburg, Tully, Miller and two other researchers collaborated on a study published last August that looked at potential crop alternatives from an environmental angle. They planted different varieties of crops, including switchgrass, at three farms experiencing intrusion and a fourth far inland with no salt issues. Then, they waited for the plants to grow and analyzed how much phosphorus they soaked up from the surrounding soil.

In the salty fields, there was no doubt: Switchgrass was the best at removing phosphorus, outdoing saltmarsh hay, weeds and other plantings. When farmers harvest the switchgrass, they also take away the phosphorus that the plant took up.

Because switchgrass is a perennial, it can simply grow back, allowing it to continue absorbing nutrients for years (instead of a single growing season). Over time, the phosphorus in the soil appears to decline, the study found.

“The message is that there are options on the edges of these fields for something that can be planted,” said Miller of the University of Delaware. “But the other side of it is ‘Is there a market?’ If there’s no incentive to plant it, farmers will just let [their fields] go to weeds.”

The costs associated with planting switchgrass are relatively low. The seeds have a comparatively small price tag, and there’s rarely a need to apply fertilizers, he said.

But farmers aren’t likely to see as big of a payday. The current market pays about $265 per acre for switchgrass while paying about $750 for corn and $400 for soybeans. And the switchgrass “market” is purely theoretical on Delmarva — at least for now.

But if the anaerobic digester shakes out as a viable solution both environmentally and economically, then coastal farmers on Delmarva might just have a new crop to plant.

Wendell Meekins can’t wait for that day. He leases the field where the corn crop failed. The only reason that switchgrass still populates the property today is because the landowner received a state grant to subsidize the planting.

The idea at the time was to ship the plant material two counties away to a manure-to-energy plant at a state prison. But the transportation costs turned out to be too high to sustain the farm’s participation, Meekins said.

For the same reason, he isn’t involved in the ACRE study either. Without some kind of intervention, Meekins said the fate of this once-fecund cornfield is sealed.

“Right now, if I look at this place,” he said, “I have little to no doubt that it will be vacant in two to three years.”