Turning Salt-Damaged Fields into Marshes Could Save Maryland Farmland—and The Chesapeake Bay

by Virginia Gewin (CivilEats) As sea levels rise, saltwater is entering farms near the bay, damaging crops and releasing legacy nutrients into already-polluted waterways. -- Kate Tully has spent the last few years sampling farm soils, ditch water, and marsh muck on Maryland’s lower eastern shore. Tully, an agroecologist at the University of Maryland, is tracking saltwater intrusion in the area, or the degree to which salt water from the nearby Chesapeake Bay has moved inland to compromise groundwater and soil. As sea levels in this region are expected to rise as much as two feet by 2050, she has found that saltwater may also be helping to unleash farm nutrients such as nitrogen and phosphorous that have been locked in the soil.

The Chesapeake Bay is so choked with agricultural pollution that lawmakers have agreed on a mandate to reduce nutrient runoff that spans six states. And yet, poultry farmers on the eastern shore produce almost 2 million pounds of chicken annually, making it one of the top poultry-producing areas in the United States. That steady supply of manure has been a cheap, plentiful source of fertilizer since the 1920s, so many farmers have applied it to their fields for decades. But there’s more manure on some fields than crops can absorb, and the resulting runoff has triggered algae blooms and a massive dead zone.

Tully is one of several scientists who recently published a study about saltwater’s impact on so-called “legacy nutrients.”

Letting marshes migrate onto salt-impacted farms provides a trap for nutrients, slowing their spill into waterways, and providing a barrier able to protect farm fields from saltwater intrusion.

The shift won’t be easy, however. It will take farmer compensation and technical support to prevent invasive species from encroaching on land. And while existing conservation programs aim to prevent nutrient runoff, they were not designed to facilitate turning abandoned farm fields into marshland.

In 2017, the U.S. Department of Agriculture’s Natural Resource Conservation Service (NRCS) began an initiative that pays landowners to create American black duck habitat. The goal is to bolster the declining waterfowl’s wintering populations in the Chesapeake and Delaware Bays. The ducks live in both salt marsh and freshwater marsh. NRCS biologist Steve Strano and colleagues have begun reaching out to landowners along marshland about creating a freshwater wetland impoundment that could also allow the marshes to migrate. A handful of farmers have expressed interest so far.

Duck habitat initiative’s permanent easement on cropland, first offered in 1995, offer a one-time payment of $4000-5000 per acre with no out-of-pocket costs to do wetland restoration—and provide perhaps the best opportunity to buy other land to farm on.

Hammond (Jessica Hammond, conservation coordinator for the non-profit Chesapeake Conservancy) says new easement programs or financial structures need to be created to recognize the multiple benefits of migrating wetlands onto existing farms.

“Once it becomes tidal marsh or wetland vegetation, you are talking about an [Army] Corps of Engineers jurisdiction to do anything else with it down the road.”

Saltwater intrusion, poor drainage and rising water levels forced farmer Bob Fitzgerald to give up on 15 acres of row crop fields that he’s farmed for 30 years. “It was better to give up on it instead of wasting seed and chemicals,” he says. “If you dig a ditch to drain land that is drowning under seawater at high tides, all you do is let saltwater in and that speeds the process of salt damage,” he says.

“Many non-farmers think you just stop farming [from farming] and let it go”, says (Jennie) Schmidt, but that’s not the case. For example, it’s important to prevent invasive, non-native salt-tolerant weeds, called phragmites, from taking over.

Poultry manure has been one of the cheapest, most effective ways to add organic matter and nutrients necessary to keep these coastal plains soils productive. Yet efforts to transport poultry manure out of the region—last year, a record-setting 249,421 tons—have made it difficult for her to continue building up organic matter on her no-till farm. READ MORE

Excerpt from Advanced Biofuels USA executive summary: In addition, this could bring economic, environmental and social benefits to the region. Producing environmental benefits from phosphorus uptake and contributing feed to the existing poultry industry, alongside producing cost-competitive biofuels has the potential to support not only a positive return on investment for a biorefinery, but also for growers and for entrepreneurs servicing this new industry.

Overall, the study finds that development of an energy beet-toSAJF supply and production chain is in its early stages, but could be economically feasible as described above depending on the results of significant research which is needed on a number of
fronts. These include: