The amount of corn planted in the Bay watershed this year returned to levels planted before the recent ethanal "boom" dramatically inflated prices, but the overall amount of all row crops planted remains near the highs of the last two years.
Corn acreage in the watershed dropped to about 1.89 million acres, down from 2.05 million in 2007, when corn prices peaked amid high demand from other nations and ethanol producers. This year's figure was slightly below the 1.91 million acres planted in 2006, before the boom.
The numbers are derived from statewide figures from the U.S. Department of Agriculture's National Agricultural Statistics Service annual acreage report. Watershed estimates are based on the percent of each crop historically planted within the Bay watershed portion of each state.
Despite the drop in corn production, the figures show that the total plantings of corn, wheat and soybeans-the three main row crops grown in the watershed-were about 3.6 acres, about the same as last year, and nearly 200,000 acres greater than in 2006.
While increased plantings are good for farmers, they can pose problems for the Bay. Corn and soybeans both leak large amounts of nitrogen into groundwater and local streams. Winter wheat can also lose significant amounts of nitrogen, especially when it's fertilized in late winter.
The spike in corn production had raised concerns about the potential for increased nutrient runoff into the Bay, as corn can lose anywhere from 25-40 pounds of nitrogen per acre, depending on weather conditions and the extent to which runoff control practices are implemented.
But while the corn acreage has subsided, the potential for runoff remains high, according to agricultural scientists, because the total amount of plantings has risen.
The region mirrored the nation with record-high soybean plantings this year. About 1.18 million acres were planted in the watershed, up from almost 1.11 million in 2008. The 450,000 acres planted statewide in Pennsylvania-the largest producer of soybeans in the watershed-is a state record.
Soybean plantings also increased in New York and Virginia, according to USDA figures.
The figures also show that the amount of "double-cropped" soybeans in the southern portion of the watershed, where the growing season is longer, has been increasing in recent years. Double cropping-when soybeans are planted immediately after the harvest of another crop, typically wheat in this region-can lead to increased runoff.
In Delaware, 62 percent of soybeans planted this year are double-cropped, up from 25 percent in 2006. In Maryland, 44 percent were double-cropped, up from 32 percent, and in Virginia 30 percent were double-cropped, an increase from 25 percent.
The 579,000 acres of winter wheat was about the same as last year, but was up about 140,000 acres from 2006.
Some of the increased crop acreage in the watershed comes from the intensification of agriculture-more crops being planted on the same land, such as double-cropping. Some also appears to have been converted from pasture or idle land.
Either scenario presents the opportunity for increased nutrient losses, according to soil scientists. Double-cropping essentially presents two opportunities for nutrient losses during the year, while conversion from low runoff pasture land to row crops also results in increased nutrient runoff.
The Bay Program estimated last year that recent changes in cropping practices may have increased the amount of nitrogen leaving croplands by about 3 million pounds a year.
Recent changes in crop plantings are the result of changing economics. Corn prices have dropped and production costs have increased since 2007. Wheat and soybean prices have been higher, and more stable, in recent years.