"If one country after the other adopts a 'starve-your-neighbour' policy, then eventually you trade smaller shares of total world production of agricultural products, and that in turn makes the prices more volatile," said Joachim von Braun, director general of the International Food Policy Research Institute in Washington.
In Argentina, a government tax on grain led to a strike by farmers that disrupted grain exports.
Vietnam and India, both major rice exporters, announced further curbs on overseas sales on Friday, sending rice higher on U.S. futures markets. Other food commodities retreated from record highs in recent days but analysts attributed that less to fundamentals and more to profit-taking by investors.
DISCONTENT
In the next decade, the price of corn could rise 27 percent, oilseeds such as soybeans by 23 percent and rice 9 percent, according to tentative forecasts in February by the OECD and the U.N.
Waves of discontent are already starting to be felt. Violent protests hit Cameroon and Burkina Faso in February. Protesters rallied in Indonesia recently and media reported deaths by starvation. In the Philippines, fast-food chains were urged to cut rice portions to counter a surge in prices.
Last year, the central bank of Australia -- where minds were focused by a two-year drought -- asked whether the surge in commodity prices could be one of the few really big ones in world history, like those of the mid-1930s or the 1970s.
Real commodity prices remained flat or even fell during the rapid industrialization of the United States and Germany in the early 20th century. But the industrialization of China, with 1.3 billion people, is on a totally different scale, it noted.
"China's population is proportionately much larger than the countries that industrialized in earlier periods and is almost double that of the current G7 nations combined," the Australian central bank said.
The emergence of China's middle class is adding hugely to demand for not just basic commodities like corn, soybeans and wheat, but also for meat, milk and other high-protein foods.
The Chinese, whose rise began in earnest in 2001, ate just 20 kilograms (44 pounds) of meat per capita in 1985. They now eat 50 kilograms (110 pounds) a year.
Each pound of beef takes about seven pounds of grain to produce, which means land that could be used to grow food for humans is being diverted to growing animal feed.
BIOFUEL TROUBLE
As the West seeks to tackle the risk of global warming, a drive towards greener fuels is compounding the world's food problems.
