Yet, agriculture remains the single largest source of bay pollution.
When it rains, nitrogen and phosphorus - two of the main ingredients in both store-bought fertilizer and chicken manure - run off the fields and into creeks. Some of that pollution will reach the Chesapeake via the Choptank River, a 68-mile tributary that twists through Queen Anne's, Talbot, Caroline and Dorchester counties.
More of that pollution is reaching the Choptank now than when the bay cleanup started. Since 1985, the nitrogen flowing into the Choptank has doubled. Phosphorus and sediments have nearly tripled, according to the U.S. Geological Survey, which monitors the river near Greensboro.
Some of that can be attributed to all the new pavement and sewage treatment plants that have come with the Delmarva Peninsula's growth. But much of it still comes from farms.
"The farmers are shooting for the best yield they can get, and in the process, they leak nitrogen," Simpson said. "It's frustrating to me, because these are good people. But they're dealing with the expectation of the market."
Unlike septic tanks, farm pollution has been the subject of much discussion in Annapolis over the years. But no one seems eager to regulate farmers, who are seen as salt-of-the-earth good guys. Aesthetically, many people would rather see a farm by the side of the road than the townhouses that could come if the owner sold the land. The O'Malley administration has proposed new rules to govern the storage and handling of manure by Maryland's largest chicken growers, but the regulations would not affect most farmers who use manure as fertilizer.
"You can take chicken manure and agricultural waste and drop it with impunity," said Winegrad, the former state senator.
The problem is that farming and conservation are fundamentally at odds. Farmers want to plant - and thus fertilize - every acre of land because that is how they make money. The bay is better served if they leave some fallow, particularly near water.
Government programs have tried to close the gap by paying farmers to plant buffers and cover crops to soak up excess fertilizer. But often, the funds aren't enough, said Jeffrey Lape, executive director of the Chesapeake Bay Program, the federal-state agency overseeing bay cleanup.
"It's tough to walk out to a farmer struggling to get by and say, 'You know, I think you need a bigger buffer,' " Lape said. "He'll look at me and say, 'You have just killed my profit margin.' "
