CANCUN, Mexico - As 146 trade ministers begin five days of global trade talks, the most modern trade summit ever -- from the ever-present cellphones to the sophisticated electronic access cards -- is dominated by the age-old issue of agriculture.

Ibrahim Coulibaly represents poor cotton farmers from Mali who say their future is being threatened by the flood of cheap cotton into world markets.

''Cotton is essential to the lives of people in West Africa,'' Coulibaly said on behalf of the West African Organization of Agricultural Producers at a news conference Tuesday.

''We expect to have a strict calendar for the end of all subsidies,'' he said, adding that for the trade negotiators to return from Cancun empty-handed would create political problems at home.

Similar demands for urgent action to correct distortions in world trade are expected to be a major part of the summit set to open today on the Yucatán peninsula.

Agriculture ''may be the make-or-break issue of this meeting,'' said Phil Bloomer, coordinator of a team from Oxfam, an international relief agency.

Still, Coulibalys voice is but one of thousands at the fifth ministerial conference of the World Trade Organization, as industry, environmental, labor and citizen groups jostle for attention from the trade ministers, who meet behind closed doors at what have become raucous and rancorous events.

Cancun has been turned upside down by the tight security: Every hotel worker must obtain access cards to go to work in the hotel zone. Thousands of police officers and soldiers patrol the Mexican resort to confine protesters to the downtown area, away from tourists and those attending the meeting.

On Monday, dozens of people reached the beach and took off their clothes in protest. On Tuesday, officers and protesters struggled at a police blockade.

U.S. Trade Representative Robert B. Zoellick, his eye on November hemispheric trade talks set for Miami, echoed the emphasis on agriculture.

''Much of the attention here is going to be on agriculture, and I think that is appropriate,'' he said in a news conference.

But, he added, the bottom line for Washington in the negotiations is market access -- lower import tariffs and similar easing measures -- for industrial products and services.

Developing countries, meanwhile, are demanding that the billion-dollar price supports and export credits used in Europe, Japan and the United States not be used to dump below-cost farm goods.

Mexican peasants are protesting the results of the North American Free Trade Agreement, charging that subsidized corn from the United States is exported below the cost of production, driving down domestic corn prices by 70 percent and forcing farmers off their land.

This, however, is much more complex than just a rich-country-poor country divide. Wealthier developing countries like Brazil want more market access for their products in Europe and the United States, something that is not an issue for a smaller, poorer country like Mali.

In the meantime, Mark Ritchie, president of the Minneapolis-based Institute for Agriculture and Trade Policy, points out that, while Mexican farmers focus their ire on the United States and corn prices, Vietnam is dumping coffee into the world market, wreaking havoc on producers in Mexico and Central and South America.