WASHINGTON, May 14 (Reuters) - Congress pushed the Bush administration on Wednesday to do more to boost global agriculture, faulting a long-term decline in foreign aid for the food crisis unfurling across the developing world.

"With proper planning, foresight and coordination, this crisis might have been managed ... What the world needs is a second green revolution," Sen. Joe Biden, chairman of the Senate Foreign Relations Committee, said in a hearing on the skyrocketing prices wreaking havoc on world food markets.

Lawmakers from both parties called for a reinvigorated U.S. response, akin to the push that raised crop yields and saved millions from starvation in Asia and beyond in the 1960s.

Food prices have risen over the past year in step with increased food demand in emerging economies, paltry harvests, record oil prices and growing biofuel production, a trend that is thrusting 100 million additional people into hunger.

At the same time, aid to fragile nations' farm sectors has dropped off in recent decades as donors like the World Bank and the U.S. government turned to other priorities like HIV/AIDS.

U.S. funding for agriculture development since 2000 has averaged just a third of what it was in the 1980s, bemoaned Sen. Dick Lugar, the committee's top Republican.

"Food shortages are likely to recur frequently, if the United States and the global community fail to ... invest in agricultural productivity in the developing world," he said.

For Lugar and other lawmakers, biotechnology and more open agricultural commerce are also promising avenues in the quest to help poor nations to feed themselves.

In that, they see eye-to-eye with the Bush administration. But it is unclear how quickly, and with how much money, the administration will respond in overhauling farm assistance.

President George W. Bush called this month for $770 million in new food and disaster assistance, including $150 million in agriculture development, for fiscal 2009.

The $150 million "will allow us to begin to reverse" that long-term decline, Henrietta Fore, administrator of the U.S. Agency for International Development, told lawmakers, stressing that the private sector would also play an important role.

"I am confident we -- the U.S. and other donors -- can stem and reverse the supply-demand imbalance," Fore said.

James Lyons, an official at Oxfam America, called for a doubling of U.S. farm aid to at least $600 million a year.

DIVISIVE ISSUE

In the short run, only food aid -- rice, cooking oil, and more -- can stanch hunger. But the buying power of aid budgets has taken a big hit this year amid high food and fuel costs.

The United Nations' World Food Program will cut 450,000 school lunches in Cambodia, and more cuts will follow.

Josette Sheeran, the agency's director, said donors like Japan and Canada were digging into their pockets, and relaxing purchasing rules, to help the agency, which faces a funding gap of at least $755 million this year.

The United States, the top food aid donor, at the same time is coming under renewed fire for its food aid purchasing rules, which require it to buy crops at home, rather than close to the crisis, tacking on time and money to aid shipments.

Andrew Natsios, a former USAID administrator, told a House hearing that the system "frequently has a depressive effect on agricultural markets, particularly in Africa."

Another divisive issue is the growing reliance on biofuels, which Congress embraced last year to help ease the U.S. dependence on foreign oil.

Ethanol, which critics say pushes up food prices by diverting food and feed crops, is forecast to consume about 33 percent of the U.S. corn crop this year.

The administration believes ethanol accounts for a tiny share of higher food prices and is quick to note the United States is moving to other biofuel sources like switchgrass.

Corn Belt lawmakers are likely to defend the program to the hilt. "Cutting ethanol production now would leave us even more vulnerable to the political whims of governments that control 80 percent of world oil reserves," Lugar said.