The amount of crop land in the Bay region will increase this year if farmers follow through on planting intentions reported to the U.S. Department of Agriculture.

The USDA's Prospective Plantings report issued March 31 indicates that farmers in Virginia, Pennsylvania, Maryland, Delaware and New York intend to grow nearly 500,000 additional acres of corn, wheat and soybeans than they did just two years ago, an increase of more than 7 percent.

That's good news for farmers, who are responding to record high commodity prices caused by increased global food demand, crop failures in other parts of the world and a growing thirst for ethanol and other biofuels in the United States.

But as the row crop acreage increases, so does the potential for pollution to the Bay.

It's unclear from the USDA report where the additional acres will come from. But corn, soybeans and wheat-which account for the overwhelming majority of cropland in the region-are all relatively high runoff crops, meaning the land conversion could result in more nitrogen, phosphorus and sediment pollution unless efforts to curb runoff are stepped up.

"The planting intentions report shows further intensification of production, and whether it is corn or soybeans or wheat, when added together, there is an increase in high nutrient loss crop production," said Tom Simpson, a soil scientist with the University of Maryland's College of Agriculture and Natural Resources who chairs the Bay Program's Nutrient Subcommittee.

"Since I feel safe in assuming that acreage is not coming from orchards or vegetables, it has to be coming from pasture, idle lands or hay, which are low nutrient loss lands," Simpson said.

Last year, corn acreage in the region increased dramatically as prices jumped to $4 a bushel-driven in part by increasing demand for ethanol-and raised concerns about its impact on the Bay.

This year, corn plantings in the region are projected to drop 130,000 acres from last year to 3.6 million acres, but will remain 175,000 acres above 2006. Corn acreage is projected to decline in Maryland, Virginia and Delaware, but increase in Pennsylvania and remain the same in New York.

Corn is a particular concern because it has a reputation for being especially "leaky" in terms of fertilizer. It loses more nitrogen under typical growing conditions than any other major crop.

Corn prices have continued to rise, approaching a record $6 a bushel this year. But the national surge in corn production last year, which came in part at the expense of other crops, sharply boosted the price of soybeans and wheat as well.

Soybean acres are predicted to jump 190,000 acres in the five states to 1.85 million acres, with record plantings predicted in both Pennsylvania and New York. That's a concern because, although little nitrogen is applied to soybeans-it "fixes" what it needs from what's in the atmosphere-which leaves large amounts of the nutrient in the soil after harvest.

Wheat acres are expected to jump from 777,000 acres in 2007 to 940,000 acres this year.

Wheat generally leaks less nitrogen than corn and soybeans, but when wheat and soybeans on grown back to back on the same field in the same year-a practice known as double-cropping-the nitrogen losses can be similar to that of corn.

Altogether, the number of acres planted in the five states is expected to increase by 223,000 acres over 2007, and by 472,000 acres over 2006.

That doesn't necessarily mean the acreage of land used for crops will grow by that amount. Some of that increase is likely caused by an increase in wheat-soybean double crops in the southern portion of the watershed, where the growing season is longer.

Nonetheless, the figures suggest a increase in the amount of land used for crops of several hundred thousand acres.

The report doesn't say where the plantings will take place. But if past patterns are followed in the states, nearly 60 percent of the additional acres would be planted in the Bay watershed.

Higher crop prices can provide a powerful incentive to help keep land in agriculture rather than being developed. But increased acreage could add up to more nutrient pollution reaching the Bay unless efforts are stepped up to control runoff.

"At a minimum, it would require greater costs to implement more best management practices to offset the increased acreage," Simpson said. Because there's already a shortfall in public money available to fund such runoff control practices, the increased implementation isn't likely to happen, he added.

A particular concern is that some new crop land will come from Conservation Reserve Program and Conservation Reserve Enhancement Program lands. In those programs, the USDA pays farmers to take environmentally sensitive lands out of production. In the decade-old CREP program, streamside lands were also planted with buffers to filter pollution.

But the 10-year contracts for the initial lands enrolled in CREP come up for renewal this year and officials have expressed concern that soaring crop prices could spur some farmers to return that acreage to production. That, they say, would result in a double blow to water quality, with streamside buffers being lost as high runoff crops are planted.

The annual USDA report is based on surveys of 86,000 farmers taken during the first two weeks of March. The estimated figures are usually within a few percent of the actual plantings, which are reported at the end of June.

The National Corn Growers Association said actual planted acreage could be higher. "We're always cautious when we review the March projections, because they are made before any seeds really enter the ground," said Ron Litterer, NCGA president. "The corn acreage projections also have a tendency to go up. Last year, for example, there was a difference of more than 3 million acres between the March estimate and the final number."

Litterer pointed out that the USDA's March report has underestimated actual corn acres in the each of the last four years.

Pressure for increased production is likely to grow, both this year and in the future. The United Nations' Food and Agriculture Organization has warned that global food prices are soaring and need to be alleviated by increased production. The U.N. in April warned that food prices and scarcity is threatening security and political stability around the globe.

In the United States, an energy bill passed last year requires that ever increasing amounts of ethanol be produced to reduce demand for oil in gasoline.

Tempering the drive for increased plantings is the rapidly increasing cost of production. Farmers are facing skyrocketing costs for fuel as well as fertilizer-nitrogen production requires large amounts of natural gas.

"One thing farmers have told us this year, and something I've seen myself, is that growers are facing tremendously higher input costs-particularly for fertilizer and diesel fuel," Litterer said. "We need access to more affordable sources of natural gas for fertilizer production and we're concerned about the impact of higher crude oil prices on farmer profitability."