The Salvadoran Army and government, acting with U.S. advice and money, have launched a major campaign to make propaganda and psychological warfare effective weapons in their battle against leftist insurgents.

The military's new emphasis on propaganda is particularly designed to lure Salvadoran rebels to desert the Farabundo Marti National Liberation Front, the guerrilla organization that has been fighting a civil war here for the past six years.

This has been accompanied by an extensive antileft publicity campaign organized by the U.S.-backed government of President Jose Napoleon Duarte with help from a Venezuelan publicity agency associated with Christian Democratic causes.

Last month, Christian Democrat Duarte named one of his trusted advisers, Julio Rey Prendes, to the new post of minister of communications and culture to help direct the effort. Rey Prendes, previously the president's chief of staff, traveled to Washington last week on a U.S. Information Agency grant for consultations with U.S. officials, including Otto Reich, the State Department's chief of public diplomacy.

The insurgent leadership and the right-wing Arena Party have charged that Duarte's government is using the propaganda campaign to smear lawful opposition from the right and the left by associating both with the violence that has plagued this country since 1979.

"Through the radio, the press and television, a veritable bombardment of propaganda is carried out daily in which images of workers on strike, combat scenes, fires and so on are mixed together," complained the leftist guerrillas' Radio Venceremos. "They obviously are trying to get across the idea vividly that workers are terrorists, in accord with government propaganda that everything opposing it is terrorist."

The increased attention to psychological warfare within the armed forces reflects availability of new funds because of sharply rising U.S. aid rather than sudden realization that winning people's hearts and minds is a good idea, according to Gen. Adolfo Blandon, the Salvadoran chief of staff. Officers say propaganda has more chance of being effective since Army forces have taken the initiative from the guerrillas in the past year.

Blandon reorganized the Army's Department 5 last year for psychological warfare, "psyops" in U.S. military jargon and "opsic" in the Salvadoran adaptation. Department 5 got special emphasis and funding beginning this year, along with a U.S. adviser seeking to apply lessons learned in Vietnam, according to the Salvadoran colonel heading the effort.

"What we want to do is take the North American propaganda methods and apply them to what we are doing here in El Salvador," he said.

Air Force observation planes have been dropping thousands of leaflets over guerrilla-held and disputed sections of the country, calling on guerrillas to turn themselves in and pledging good treatment by the Army. Similar appeals have been made over the radio, including some spots with soft feminine voices designed to evoke mothers or sweethearts, said the officer, who requested anonymity.

One leaflet shows a photograph of two teen-age boys smiling and savoring cold beers. They are identified as Armando and Chando, two rebels who the Army said surrendered in the first week of July after serving the Revolutionary Central American Workers' Party, one of five groups in the rebel front.

The leaflet says in Spanish, "Your former comrades Armando and Chando abandoned the ranks of subversion because they do not want to go on causing harm to their people. Today they are citizens who enjoy their freedom. You also can do it. The armed forces will protect you."

Other leaflets and posters have described the turnaround of Miguel Castellanos, a former Central Committee member of the Popular Liberation Forces, the second-largest guerrilla group. Castellanos, whose name until he went underground was Napoleon Romero Garcia, has cooperated extensively with the government since his capture this spring and has appealed repeatedly to guerrillas to give themselves up. He is expected to travel to the United States and Europe soon to tell his story, according to the Army.

In addition to such testimony, the Army has accelerated such civic-action programs as distribution of free clothes or food in poor villages. In a recent ceremony to hand out used clothes in northern El Salvador, Army loudspeakers broadcast soft music and sermonettes about motherhood while townsfolk filed by in front of the Catholic Church to pick up corduroy jackets, trousers, plastic purses and, in one case, a necktie.

"The effort of the Army is not only to make war," said Col. Ivan Diaz, the officer in charge of the handout detail.

The psychological warfare effort so far has produced no marked change in the rate of guerrilla desertions, which the Army put at 456 in the last six months.

In its civilian campaign, the government has broadcast repeated radio and television appeals for Salvadorans to denounce anyone they suspect of having links to terrorism on the right or the left. In the publicity spots, the Secret Anticommunist Army, a right-wing terror group that has claimed responsibility for assassinations, is equated with the leftist rebel front, some of whose components also have claimed responsibility for assassinations.

The government has received assistance in its propaganda effort from the Venezuelan Institute for Popular Education, or IVEPO by its Spanish initials. The consulting firm is linked to prominent Venezuelan Christian Democrats and helped Duarte during his election campaign last year.

U.S. congressional and administration sources said then that up to $2 million in CIA funds were channeled to Duarte's campaign. IVEPO was said by a well-placed source to have been a conduit. IVEPO's director here, Jose Miguel Fritis, denied that allegation at the time.