A study recently published in the journal Nature Sustainability has highlighted a pressing concern for the Delmarva Peninsula. Farms situated in low-lying areas bordering tidal bays and creeks face an escalating risk of saltwater intrusion, posing a significant threat to agricultural lands.
Contrary to overtaking entire fields, the encroachment of salt appears insidiously at the peripheries, slowly eroding the edges of farmland. The study estimates a substantial increase in Delmarva Peninsula farmland succumbing to salt patches, surging to over 2,200 acres from 2011 to 2017. This alarming trend translates to potential annual crop losses of up to $107 million in the region, according to the researchers.
Kate Tully, an agroecologist at the University of Maryland and one of the study’s authors, expressed surprise at the extent of saltwater intrusion. “There is an important need for us to come up with a suite of solutions for farmers and landowners on the Eastern Shore,” she emphasized.
Jarrod Miller, a soil expert at the University of Delaware and part of the research team, highlighted the cumulative impact, stating, “It could have been just a foot along the edge of these fields. But when you add it up, it’s a lot of acreage across the region.”
The visible effects of this intrusion manifest as bare white sand and salt swathes in affected areas, with intermittent vegetation in places where salt has recently encroached.
Over the past five years, researchers from multiple institutions, including George Washington University and the University of Delaware, have diligently studied threatened farmland on the Delmarva Peninsula. The team, led by Tully, Miller, and colleagues, has aimed to map the extent of saltwater intrusion, forecast its trajectory, and assess the viability of cultivating more salt-tolerant crops like sorghum and switchgrass.
Their latest study utilized various technologies, including aerial photographs, satellite imaging, and soil sampling, to estimate the spread of salt patches. Moreover, the team developed software leveraging machine learning that can identify different land cover types with an impressive 85% accuracy from satellite-derived data.
The findings revealed a notable increase in salt patches in Maryland and Virginia. Maryland witnessed an approximately 80% growth in these patches, surpassing 1,000 acres by 2017. Meanwhile, although Eastern Shore of Virginia experienced less impact, the recorded 300 acres in 2017 marked a substantial 243% surge since 2011.
The intrusion of saltwater isn’t limited to coastal areas, with inland regions also experiencing significant impacts. Caroline County in Maryland, the sole land-locked county in Delmarva, saw a staggering 450% expansion in salt patches.
While salt patches presently constitute a minor portion of the landscape, accounting for less than 1% of total farmland in any given county, they represent just one facet of a broader issue across the peninsula. In the study period, around 20,000 acres of farmland transformed into marshland, an area approximately half the size of the District of Columbia.
Pinki Mondal of the University of Delaware, the lead author of the paper, emphasized the urgency of addressing this evolving landscape, stating, “We can’t wait and watch what is going on.” Mondal has developed a mobile app displaying the changes in Delmarva’s land cover from 2011 to 2017, showcasing salt patches delineated in purple and farmland in orange.
The study underscores the critical need for proactive measures to safeguard agricultural lands from saltwater intrusion, urging immediate attention to protect the region’s farming communities and their livelihoods.