CALL it the free-trade serenade.Latin American presidents sang in unison for the first time at the Ibero-American Summit, a gathering here last week of leaders from 21 countries, including Spain and Portugal. But it was the off-key, grey-bearded Cuban in the khaki uniform who garnered most of the press's attention. While dictator Fidel Castro called the summit a "brilliant initiative" of "historic character," he derided the economic solutions being adopted by the rest of Latin America. "There's always a new siren song," Mr. Castro said. He referred to past plans such as the "Alliance for Progress,The Baker Plan,The Brady Plan," and "The Initiative for the Americas" as fantasies. But Castro's socialist dissonance was largely drowned out by affirmations of current political and economic trends. "In Ibero-America, we've witnessed the transition from dictatorships to democracies.... The people have chosen democracy," said Costa Rican President Rafael Angel Calderon Fournier. And Spain's Socialist President Felipe Gonzalez Marquez not too subtly put down Castro's leftist ideology. "We should leave it to the parliaments and the people to write their history and relegate the exploits of guerrillas to the imagination of novelists." During the opening speeches when Argentine President Carlos Saul Menem praised President Bush's year-old initiative to create a hemispheric free-trade zone, Castro was visibly upset. At a break in the meeting, Castro was surrounded by reporters. At first jovial, when a reporter asked about free democratic elections in Cuba, the dictator abruptly walked away muttering about "interminable defamation." The summit produced no new initiatives, no formal policy response to the Bush initiative. But the final declaration signed by all leaders (including Castro) commits them to: * Fortify the democratic process. * Support economic integration. * Adopt mechanisms to promote and protect human rights. * Cooperate in the fight against narcotics trafficking and demand that drug consuming countries intensify their efforts to reduce drug use. * Seek solutions to environmental degradation, including rejecting technologies that pollute. * Create an Ibero-American fund, with support from international groups, to aid indigenous peoples. Based on Spain's experience in the European Common market, President Gonzalez said Latin America is developing the common base, and reaching "a democratic density" crucial for integration. The summit also blunted criticism of President Carlos Salinas de Gortari's plans for a free-trade pact with Canada and the United States. Opponents have said Mr. Salinas has sacrificed Mexican sovereignty to the northern "imperialists" and turned his back on his cultural brothers to the south. The summit encouraged Latin nations to embrace economic integration, which would include closer ties to the big North American consumer market. Uruguay's President Luis Alberto Lacalle, however, did caution his colleagues not to raise expectations too high for what economic integration will produce. "We have to be careful not to make new mistakes by sowing dreams when the people are asking us for realities." Despite smaller regional trade groups working toward integration, trade between Latin American countries remains low. Part of the problem is poor transportation and communication links between relatively undeveloped nations. As Guatemala's President Jorge Serrano Elias pointed out, it's far easier to trade with Europe and the US. "Argentina, Brazil, and Chile are big, important markets we'd like to participate in, but there are no airlines connecting [our country directly] to them," he said. Apart from the formal summit meeting, heads of state crisscrossed the lush Camino Real Hotel courtyard to hold private meetings in the clusters of ground-floor rooms allocated to each nation. The presidents of Colombia, Mexico, and Venezuela met before the summit to sign an agreement to form a free-trade zone by the start of 1992. The same "Group of Three," plus Gonzalez of Spain, urged El Salvador's President Alfredo Cristiani to keep El Salvador's peace talks moving. Mr. Cristiani later described Castro's signing of the summit declaration as a positive step. Cuba has been accused of providing weapons to leftist rebels in El Salvador. The declaration includes a commitment to support the peace negotiations and efforts to cut arms trafficking. Despite the media hordes, which were eager to give him a forum, Castro kept a low profile. Unlike many leaders, he held no press conference. And he inexplicably canceled a meeting with Guadalajara businessmen. But Castro did take home a consolation prize. Chile and Colombia agreed to reestablish consular and commercial relations after a three-decade break. The next Ibero-American summit will be held in Madrid in mid-1992, the 500th anniversary of Christopher Columbus's discovery of the new world. In following years, Brazil, Colombia, and Argentina will host the meeting.