WASHINGTON - A senator from the U.S. Corn Belt filed an amendment on Tuesday that would bar federal regulators from considering how land is used overseas when they write rules to expand use of biofuels.

Iowa Senator Tom Harkin filed the amendment while the Senate was considering the annual funding bill for the Interior Department and related agencies, said an aide. It was not immediately clear when the amendment would be debated.

The Environmental Protection Agency proposed a regulation earlier this year that requires advanced biofuels to have greenhouse gas emissions that are 40 percent lower than petroleum from creation through consumption.

But farm groups and ethanol makers say the EPA wrongly included how land may be converted to crops overseas in its formula for measuring greenhouse gases. They say there is little or no connection between U.S. production of crops for biofuels and the amount of land converted to crops overseas. Higher yields are one way to preclude the need for more crop land, they said.

Environmentalists have defended the formula as cutting edge work that gives a full account of biofuel's impact. They say if more U.S. land is devoted to biofuel crops, farmers in other nations have to grow more crops for food, which could mean deforestation or converting grassland to crops.

The 2007 energy law guarantees the use of 36 billion gallons (136 billion liters) of biofuels by 2022, 15 billion gallons from conventional biofuels, such as corn-based ethanol, and 21 billion gallons from advanced biofuels such as cellulosic ethanol.

(Reporting by Charles Abbott; Editing by Lisa Shumaker

Energy