Coastal farmers face an increasingly salty problem

August 1, 2023

Corn and soybeans drive the agricultural economy of Delmarva, a peninsula composed of the coastal shores of Maryland, Delaware and Virginia. But the farmland on which those grains are grown is at risk. Saltwater is seeping into the soil, leaving it unproductive and unprofitable. Slowly, it appears Delmarva farmland is turning into marshland, and similar stories are playing out across other coastal lands.

“I’ve been trying a little bit of everything to get (crops) to grow … but I’m not having a whole lot of luck,” said Larry Beauchamp, a farmland manager who shared his efforts to restore an abandoned, salt-ladened plot of land in Somerset County, Maryland, in a story from the University of Maryland’s Harry R. Hughes Center for Agro-Ecology.

“It’s unbelievable how much of a difference there is [from 30 years ago],” Beauchamp continued. “Now it just seems like it’s accelerating, and I don’t know what the answer is.”

Researchers at the Hughes Center, University of Maryland Agroecology Lab, the University of Delaware and George Washington University are collecting data on plant and soil health in salt-impacted fields to develop best management strategies for farmers and landowners.

So far, the researchers’ biggest piece of advice to farmers is to switch from corn to more salt-tolerant crops, like soybean, barley and sorghum. The growing conditions are still not ideal, though, and farmers often choose to cut their losses and move to different fields.

The question remains, how widespread is the saltwater intrusion issue? To find out, researchers have reviewed hundreds of aerial and satellite images. They are getting a better, overhead look at saltwater intrusion in Delmarva and how much it costs.

Their findings, “The spread and cost of saltwater intrusion in the US Mid-Atlantic,” published in Nature Sustainability, were concerning.

Visible salt patches nearly doubled from 2011 to 2017, but those aren’t the only parts of field affected. The effects of high salinity are seen hundreds of meters beyond those obvious salt zones. From 2011 to 2017, the amount of farmland within 200 meters of visible salt patches also rose, between 68% in Delaware and 93% in Maryland. Researchers estimate annual economic losses of between $39.4 million under 100% soybean and $107.5 million under 100% corn production, on the basis of assumed 100% profit loss in at-risk farmlands within 200 meters of salt patches in 2016-2017.

“This project pairs field data on soil salinity with geospatial data to help us better understand the extent of saltwater intrusion in the Delmarva,” says Kate Tully, associate professor of agroecology at the University of Maryland, who contributed to the study. “Saltwater intrusion often happens in advance of sea level rise, which is why we call it ‘the invisible flood.’ This research is the first visualization of this often invisible symptom of climate change.”

Researchers are advocating for policy that would give farmers short- and long-term solutions.

In the short-term, Pinki Mondal, Ph.D., assistant professor at University of Delaware and lead researcher on the project, says reducing farm inputs, adding gypsum, crop insurance and planting salt-tolerant crops could help farmers maintain their profits. Eventually, though, these short-term solutions will prove unsustainable. These farmlands will be lost.

Long-term, Mondal suggests letting the land do what it will do: convert to marshland. If controlled conversion to marsh is allowed, it could create wildlife habitat and provide a buffer that protects productive farmland against further soil salinization.

Farmer needs must be considered, whatever the next step. This kind of science-based, farmer-focused research is absolutely critical for helping farmers address the challenges they face today and giving them insight into issues they should expect to face in the future.

The researchers have shared their datasets through a public repository and a web-based/mobile app to be “used for crafting new incentive programs for the landowners who need them most in this rapidly changing coastal landscape,” Mondal says.

Solutions from the Land hopes policymakers and farmer organizations take advantage of this research to inform their programs and policies for farmers dealing with saltwater intrusion.

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