Nearly one in five acres of Maryland farmland has enough phosphorus in its soil to potentially threaten local waterways and the Chesapeake Bay, according to new state data released Monday.So, if the farms aren't as big a problem as had been predicted by the EPA models, who is the problem? Could it be the nutrients from above the Conowingo Dam, and the sewage treatment plants around the Bal-Wash corridor, as the farmers had claimed?
Soil sampling results collected since last summer by the Department of Agriculture show that about 18 percent of all fields statewide have elevated phosphorus levels. And on the lower Eastern Shore — in the heart of the state’s poultry industry, where phosphorus-rich chicken manure is widely used as fertilizer— data indicate that two out of every three farmed acres have high enough levels of the plant nutrient to pose a risk to water quality.
While more analysis is needed, the phosphorus concentrations in those farm soils are such that at least some of the plant nutrient could be seeping or running off the land and feeding the Bay’s algae blooms and oxygen-starved dead zones.
But the problem apparently is not as extensive or severe as earlier estimates made it out to be, state officials said. The sampling shows that 82 percent of farm soils statewide are low in phosphorus, they noted, and there is ample farmland even on the Eastern Shore where manure could safely be spread.
“Assumptions were made that phosphorus was higher than it is,” said Hans Schmidt, an assistant agriculture secretary and a mid-Shore grain farmer himself.
Spurred by warnings about elevated phosphorus levels in Bay tributaries, former Gov. Martin O’Malley had proposed new regulations that would restrict farmers’ use of animal manure as fertilizer on soils with elevated phosphorus levels.