When ecologists gather in Baltimore, Md., this August for the 100th Annual Meeting of the Ecological Society of America, special attention will fall on the local Chesapeake Bay watershed, with field trips and research presentations exploring its rich wildlife and social history. At symposia, poster exhibits, and site visits, ecologists will have opportunities to discuss the latest research and experiences working with stakeholders in the region to improve the health of the nation's largest estuary.
Chesapeake Bay bears a heavy pollution burden from the growing metropolitan centers and vibrant agricultural activity in the watershed. In the last fifty years, too many nutrients have poured into the watershed, causing large fish kills and habitat damage in the bay.
Nitrogen and phosphorus draining from farm fields, livestock manure, sewage treatment plants, industry, and car exhaust are powerful fertilizers that feed blooms of algae in the bay. Sudden population explosions of algae pull oxygen from the water in the bay and change its acidity, which stresses aquatic animals and can even lead to "dead zones" empty of economically valuable fish and shellfish. Murky water can block enough sunlight to harm or kill native aquatic plants, destroying critical habitat for Chesapeake Bay fish and other aquatic animals. Some algae are toxic, presenting a direct threat to the health of people and wildlife.
Roughly 100,000 streams and 50 major creeks and rivers drain into the bay form the enormous 64,000-square-mile watershed, flowing through agricultural lands, industrial centers, and some of the oldest and densest municipalities in the United States, including Washington, Baltimore, and Richmond. Encompassing parts of Delaware, Maryland, New York, Pennsylvania, Virginia, West Virginia, and Washington D.C., the Chesapeake watershed is home to 27 million residents.
On December 29, 2010, the U.S. Environmental Protection Agency, acting under the authority of the Clean Water Act, instituted a comprehensive "pollution diet" to address the slow progress on water quality problems in the watershed. The Chesapeake Bay Total Maximum Daily Loads (TMDL) sets pollution limits for nitrogen, phosphorus, and sediment loads entering water bodies and includes accountability measures.
Manure from the many poultry farms in the Chesapeake watershed is a major source of excess nitrogen entering the bay. Maryland alone has 574 large-scale operations, each concentrating 37,500 or more birds in one place. Many are on the Eastern Shore. Disposing of all that chicken waste is a big problem for the farms; nearly one in five large operations has been fined by the State of Maryland recently for violating reporting requirements.
Nutrient solutions for agriculture: engaging rural residents and farmers
Cooking chicken manure into charcoal, or biochar, can turn a pollution problem into a potential farming resource. Biochar is an organic fertilizer that retains nitrogen in soil longer than inorganic nitrogen fertilizers and also captures the carbon in the manure in a stable form, returning it to the soil.
Rebecca Ryals of Brown University has compared plant growth and nutrient retention agricultural fields fertilized with biochar, raw manure, composted manure, and inorganic nitrogen fertilizer (urea). Her presentation is part of an organized session of talks about "Putting agroecology to work: from science to practice and policy," on August 12. Farmers are often willing to try new methods that improve ecological outcomes, but need economic and logistical support to make implementation practical. Ryals will also talk about the opportunities and barriers to implementing biochar use in the Chesapeake Bay watershed. Mari-Vaughn Johnson, an agronomist at the US Department of Agriculture's Blackland Research and Extension Center in Temple, Texas, will follow Ryals with a USDA National Resources Conservation Service case study report on conservation gains through voluntary actions by private land owners in the Chesapeake Bay region.
EPA regulations on TDMLs of nitrogen, phosphorus, and sediment in Chesapeake waterways are powerful tools for encouraging land use practices based on ecological science. But unequal pressures to adopt Best Management Practices have often left the agricultural community feeling unfairly blamed for nutrient pollution problems in the Chesapeake Bay watershed.
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