Zoellick and U.S. Agriculture Secretary Ann Veneman are leading the U.S. delegation to the Cairns Group meeting in this South American resort. The American delegation is participating in the group's 22nd Ministerial Meeting as a guest.

Among the topics being discussed was an upcoming ministerial meeting of the World Trade Organization in Doha, Qatar. Brazil and Argentina have said that if agriculture reform isn't part of the November talks in Qatar, there shouldn't be another round.

After emerging from a meeting Monday with Uruguayan President Jorge Batlle, Zoellick said, ''We talked about trying to work together with Cairns and others to try and make the launch in Doha a success.''

Zoellick and Veneman also were meeting with foreign ministers from the Southern Cone Common Market, or Mercosur, to discuss a possible U.S.-Mercosur free trade area. Mercosur, the world's third-largest trade bloc, comprises Argentina, Brazil, Paraguay and Uruguay. Bolivia and Chile are associate members.

''We talked about an informal four-plus-one meeting we'll have ... to prepare for the discussions we'll have in Washington during September,'' Zoellick told reporters.

All six countries are also members of the Cairns Group of 17 agricultural exporting nations formed in 1986 to put farm trade reform on the global trade agenda. Its members account for about one-third of world farm exports and also include Australia, Canada, Indonesia, Malaysia, Thailand and South Africa.

Although Washington subsidizes its farmers and agricultural exports to the tune of $92 billion a year, U.S. delegations are routinely invited to participate in Cairns Group meetings.

So far the United States has only held bilateral talks with host country Uruguay, though Agriculture Secretary Veneman said a meeting with Brazil is scheduled.

Brazil, along with Argentina, has taken a hard-line stance that if agriculture reform isn't part of the WTO talks in Qatar in November, then there shouldn't be another round.

Veneman acknowledged the importance of agriculture to the Brazilians. ''But agriculture is very important for us as well. And any global round that goes forward, agriculture for many countries, particularly the Cairns Group and the United States, is going to be very central to any negotiations.''

The United States and Brazil, two of the world's biggest agricultural powerhouses, have a long history of trade disputes. U.S. sugar beet farmers fear that trade talks could allow Brazilian producers to flood the American market with a less expensive product.

In addition, the Brazilian government requires all gasoline in the South American country contain a 22 percent mix of cane-based ethanol. U.S. farmers often point to Brazil's ethanol program as a subsidy of sorts for the country's sugar cane industry.