How Corn Ethanol Could Pollute the Bay

Despite rising food prices, it seems that nearly everyone is turning to corn-based ethanol as their choice for alternative fuel. Hidden behind these headlines, though, is an equally important but less visible cost: water pollution.

Corn is a "leaky" crop, losing more nitrogen per acre than most other crops. In the Washington region, much of this excess nitrogen ends up polluting the Chesapeake Bay and robbing fish, crabs and oysters of oxygen.

For farmers, the demand for alternative fuels has brought much-needed, and deserved, increases in corn prices. Unfortunately, this summer's drought will keep mid-Atlantic farmers from realizing their potential windfall, and any unused nitrogen will wash into the bay this winter.

Nationally, farmers planted 16 million new acres of corn for ethanol. Maryland farmers provided 200,000 of these acres, but over time, production could grow to as much as 1 million acres -- yielding an extra 8 million to 16 million pounds of nitrogen in the state's runoff.

Regional officials are already struggling to reduce nitrogen loads by 100 million pounds. This additional load could set back regional water quality efforts by three to five years. This thirst for grain-based ethanol will add to the woes of our weakened ecosystems. Three strategies, however, could reduce and perhaps reverse the damage:

� Plugging the nitrogen leaks. Many farming methods can yield good crops with less nitrogen loss. These practices are used to some extent, but they need to be more diligently applied, and states need to ensure that all farmers adhere to them. With expanded production to support ethanol, these changes are needed now.

� Expanding conservation support. To offset the pressure of ethanol on crop production, policymakers should expand the federal and state programs that fund farmers who implement conservation practices. Congress is currently reauthorizing the farm bill and should take this opportunity to expand conservation efforts to offset the impacts of ethanol.

� Looking beyond corn. Research indicates that we can use native prairie grasses (such as switch grass) or fast-growing trees to fuel ethanol production. Cellulosic ethanol converts plant matter into ethanol rather than using edible grain. Production, handling and processing problems, however, may delay commercialization for another decade.

Compared with corn, switch grass loses little nitrogen, traps greenhouse gases and builds better soils. Regional farmers could realize multiple income streams by harvesting switch grass for ethanol production, selling nitrogen and carbon reduction credits to sewage treatment and power plants, and collecting federal incentives for improving soils. When added together, switch grass is worth investing in. And that's before figuring in the benefits to our region's coastal waterways.

We need to accelerate cellulosic ethanol development as we deepen our investment in corn ethanol. Without better management practices and policies, feeding corn to our cars will continue to pose a huge threat to our coastal waterways, while also threatening food supplies and prices. If ethanol is to become a truly "green" fuel, we must look beyond corn and toward cellulosic ethanol from prairie grasses.

-- Tom Simpson -- Daphne Pee

College Park

The writers are, respectively, professor and coordinator, as well as regional liaison, at the Mid-Atlantic Water Program of the Department of Environmental Science and Technology at the University of Maryland-College Park.