The chicken industry on the Delmarva Peninsula generates about 850,000 tons of poultry litter each year, frequently applied as fertilizer to area fields. The environmental concern is potentially high amounts of nitrogen and phosphorus in the litter can leach into the Chesapeake Bay watershed, leading to a nutrient-induced increase in phytoplankton (eutrophication) that can damage the bay’s fisheries.
A five-year, $5 million grant-funded project being undertaken by the University of Maryland Eastern Shore looks to utilize the abundance of litter to boost sustainable biogas production at local facilities, mitigate climate change factors and create new streams of revenue for farmers.
Funded through the U.S. Department of Agriculture’s Natural Resources Conservation Service, the project centers around the anaerobic digestion of chicken litter, where organic matter is broken down by bacteria. The byproducts are then used as biofuel and fertilizer on cover cropped fields, particularly switchgrass, as a source of sustainable biomass feedstock.
“The digestion process utilizes much of the chicken litter to produce methane (a biogas) that can be used (as biofuel) to power local farm operations. It also captures nutrients and creates digestate, the leftovers from the digestion process that contains carbon and stable forms of nitrogen and phosphorus (key components of fertilizer) that are not easily leached,” said Jonathan Cumming, (above) professor and chair of UMES’ Department of Natural Sciences, and principal investigator for the project. The process, he said, helps improve carbon pools and prevents nutrient leaching to the bay.
“We get great soil at the end of the day,” Cumming said.
“One challenge to the anaerobic digestion process when it comes to chicken litter is the high nutrient levels,” Cumming said. To optimize digestion, more carbon needs to be added. “That’s where the cover crops and switchgrass come in.”
Plant residues are high in carbon and represent a natural option to boost digestion efficiency, Cumming explained. Harvesting winter cover crops instead of them being “burned down” as is the current practice, not only provides a source of carbon for the AD process, it also adds a new revenue stream for farmers.
“Farmers also gain advantages with switchgrass because it is a perennial and can be harvested multiple times,” Cumming said.
Switchgrass also plays a critical role in mitigating climate change.
“We can identify cultivars that can be grown on marginal soils, including those affected by saltwater intrusion, bringing more land into production for farmers,” Cumming said. As a perennial, it also captures atmospheric carbon dioxide and transfers this carbon to the soil due to its extensive root systems, unlike regular cover crops.
“This carbon enters the soil ecosystem where it is stabilized and stored for the long term,” Cumming added, “which gets it out of the atmosphere where it contributes to the greenhouse effect.” Ultimately, this and other climate-smart practices will help mitigate climate change and reduce the associated impacts on temperatures and extreme weather events.
“The study will evaluate whether switchgrass can become as valuable as corn as a commodity, by weighing a farmer’s time commitment, fertilizer and seed costs, and market demand with the environmental benefits of committing to cover crop or switchgrass production,” Cumming said. “The ecological benefits are monumental and, if these can be validated through the anaerobic digestion and carbon markets, small farmers and the world have a lot to gain.”
The project is in partnership with researchers at the University of Maryland, College Park and Planet Found Energy Development LLC in Pocomoke City, a subsidiary of Chesapeake Utilities Corporation. The associated grant is part of USDA-NRCS’ Partnerships for Climate Smart Commodities program, aimed at building markets and investing in America’s climate-smart farmers, ranchers and forest owners. Its task is strengthening the country’s rural and agricultural communities while substantially reducing environmental externalities of production and mitigating climate change.
Photos by Todd Dudek, Ag Communications, University of Maryland Eastern Shore, School of Agricultural and Natural Sciences, UMES Extension, tdudek@umes.edu.
