The Obama administration tried to strike a cautious compromise Wednesday in setting new biofuel quotas for a controversial renewable fuels program that pits Big Oil against Corn Belt interests.

The Environmental Protection Agency proposed compelling refiners to blend 18.8 billion gallons of biofuel into the U.S. gasoline and diesel supply next year, with no more than 14.8 billion gallons of that coming from conventional corn-based ethanol. The overall number represents a modest increase over the 18.11 billion gallons of total renewable fuels the agency required for 2016.

But it is still far below a 24 billion gallon biofuel target that lawmakers established in a 2007 statute, and it dips below the law’s 15 billion cap on conventional renewable fuel, limiting the potential for ethanol producers such as POET LLC, Green Plains Inc. and Pacific Ethanol Inc.

Biofuel backers blasted the EPA’s plan.

“The agency continues to cater to the oil industry by relying upon an illegal interpretation of its waiver authority and concern over a blend wall that the oil industry itself is creating,” said Bob Dinneen, head of the Renewable Fuels Association, said in an e-mailed statement.