Fertilizers and genetically modified seeds aren't the only answers to growing more food. In Cambodia, in response to calls for the country to grow more of its own rice, a major aid organization, Oxfam America, is pursuing a cheaper solution.

It is encouraging rice farmers to follow a list of a dozen or so rules -- things like plant seedlings closer to the surface, in rows, individually and not in handfuls at a time -- that taken together could double a farmer's harvest, according to Yang Saing Koma, a Cambodian agriculturalist who's helping wage a campaign against age-old techniques. The techniques give seeds more oxygen and more room to grow into larger plants with more rice kernels, he said.

"There is a big potential to increase rice production using existing practices but you have to change your mindset, your attitude," he said.

First developed by a Jesuit priest working with rice producers in Madagascar, the ideas have become known in Third World development circles as the "System for Rice Intensification," or SRI. Promotion of the farming technique has become a cottage industry for groups working with the world's poor, with everyone from Oxfam to Cornell University teaching SRI to farmers from Cambodia to -- literally -- Timbuktu.

"It's so easy that one of its problems is that people think you're pulling their leg," said Brian Lund, regional director for Oxfam America's office in Cambodia. "It can double the yield, but when your neighbor sees that he'll say, 'Right, you must have slipped out last night and put some fertilizer on that.'"

Farmers use less water, less fertilizer and fewer seeds, but in the end the amount of rice produced per acre is greater than traditional practices, say proponents. And with less fertilizer to buy, farmers save money.

Koma, in partnership with Oxfam, recruited 38 farmers in 2000 to try SRI practices. He said he has more than 100,000 farmers using the system today.