Mr. Goldstein said that rather than speed up the process of producing more ethanol, Congress should “step back and reflect on the damage we have already done.”

By contrast, ethanol advocates in Congress are pushing to accelerate research into cellulosic sources with the stated goal of speeding the timetable for when corn can be supplemented — or supplanted — as the chief ethanol crop.

Image Last May, workers prepared an ethanol plant intended to produce 40 million gallons a year in Windsor, Colo., north of Denver. Credit... Neal Ulevich/Bloomberg News

“We need additional funds for transitioning to making more energy crops for our national security,” Senator Tom Harkin, an Iowa Democrat and the new chairman of the Senate Agriculture Committee, said in an interview earlier this month.”

The agriculture secretary, Mike Johanns, said there will be an “adjustment period“ for ethanol that will last a few years. But he is confident that more corn will emerge to ease the pain of higher grain prices, as seed companies improve yields and farmers shift their acreage from other crops. “When you look at the whole constellation of issues, and advancements that are out there, it is a very encouraging time for agriculture,” Mr. Johanns said in an interview.

The race to crack the code to produce cellulosic ethanol more efficiently has attracted dozens of researchers, venture capitalists and even the interest of major oil companies like BP and Chevron. Vinod Khosla, a major venture capitalist who has poured money into seven different start-up companies, has been pushing Washington lawmakers to set more aggressive targets to ensure that the demand for corn moves beyond corn. “If I am going to take the risk, the market has to be big,” Mr. Khosla said.

The Renewable Fuels Association is trying to balance the competing concerns. The organization was not always interested in rapid expansion, particularly if that meant allowing competition for A.D.M. from sources like Brazilian sugar. David Hallberg, the association’s founding president, said he left after four years in the job partly because he grew tired of disputes with A.D.M. executives over the future direction of the industry.