Aquilino Torrez was working his tiny plot in a jungle river settlement near here one day in 1981 when a column of the M-19, Colombia's left-wing nationalist guerrilla group, came and plucked him up.

A commercial plane hijacked by the insurgents and packed with arms had just crash-landed in the jungle nearby, and the M-19, Torrez says, "needed people to unload."

"They said it would only be two days' work," Torrez says now in the raspy, slurred Spanish of this region's poor farmers. "But then the Army came with the repression, and they knew who had gone along. I was afraid to go back, and so without any will of my own, I stayed on."

In this way, Torrez, 38, a peasant with a paunch, a family of six and no notion of politics, became one of the thousands swept up in Colombia's endless guerrilla wars. The conflicts have slowly bled this country of lives and development for more than 25 years without cease, with little change, and often, with scant international notice.

While Central American revolution has become a focus of U.S. policy, Colombia--just south of that region--has no American military advisers, and the Reagan administration is seeking to transfer its 1983 military aid earmarked for Colombia to El Salvador.

But there are about 3,000 armed guerrillas operating through the country, backed at times by Cuba and Libya. And in this wild southern region of mountains and jungle, the history of violence is reaching a potentially crucial juncture.

Under a major new program, millions of dollars in development aid from Bogota, the capital, are being pumped into Florencia, and an unconditional amnesty has been extended to guerrillas both in the field and in the jails.

Once trapped between aggressive guerrilla fronts and the avenging Army, thousands of cattleman, farmers and poor peasants like Torrez are being offered a slim chance to start over.

"It is the first step in a long process," said Nelson Valencia Mendez, the mayor of Florencia who is helping Torrez secure a $5,700 loan to buy land under one of the new "pacification" programs. "We can't expect that six months of amnesty and rehabilitation will solve 30 years of violence. It is something you must learn as you go along."

The effort to pacify Florencia and the sprawling Caqueta Department around it is part of a nationwide program that has become both the centerpiece of President Belisario Betancur's Conservative government and a potential model for other Latin American countries.

Abandoning previous governments' policies of military repression that failed to eliminate Colombia's four major guerrilla groups, Betancur created a special Peace Commission in September and has since pushed a program of amnesty, dialogue with guerrilla leaders and wide-ranging political and economic reforms.

The results have been mixed. To many Colombian leaders, they are disappointing. While many guerrilla leaders at first accepted the program and checked violent activities, major sectors of the armed movements--including most of the M-19--recently announced their intention to return to war. Since the amnesty became law last November, more than 100 persons--including 39 soldiers--have died in the violence.

Government officials insist that the peace program is still active, and in the current confusion of statements and counterstatements by different guerrilla groups, tend to dismiss the new reports of conflict and the mimeographed leaflets announcing offensives.

"There are a lot of different reports and a thousand irritations," said Otto Morales Benitez, the president of the Peace Commission, in an interview. "But everything that is happening indicates that we are moving toward pacification."

For Colombia, efforts to end political violence encounter special difficulties. Guerrilla groups have nourished on underdevelopment and economic inequalities familiar to the region. But this is also a nation where both guerrilla warfare and national efforts at conciliation have a long historical tradition.

In the 19th century, Colombia endured eight major civil wars, most of them between partisans of its traditional Liberal and Conservative parties. In 1948, another major conflict broke out between the two parties, and in the following decade, at least 100,000 died in mostly rural guerrilla warfare known as La Violencia.

Now, as the new peace program begins, Caqueta has become a region controlled by a more recent subculture of violence. There are six major leftist guerrilla "fronts" in the department--groups of 60 to 80 fighters under a decentralized command--and nearly every landowner and businessman in the area feels their touch, even as peasants are recruited or forcibly conscripted.

Cattlemen taking refuge in Florencia say they are used to paying the "cattle vaccination," a regular fee extracted by the guerrillas for each acre of land or head of cattle. Even cultivators of coca, the raw material of illegal cocaine, are said by military officials to be charged a fee for every harvest of leaves.

The military, in turn, is accused by church-based human rights workers of acting with arbitrary force. Rural residents have been tortured or killed by squads searching for guerrillas. Leaders of Caqueta's human rights committee say they documented 164 civilian deaths at the hands of the Army between late 1979 and mid-1982.

Although Caqueta's lands extend over 60,000 square miles--or almost 10 percent of Colombia's total area--only 40,000 of the region's 300,000 people now live in the countryside, Army officials say. The rest have fled to the towns, and Florencia, with two tiny factories and a few roughly paved streets, now has a population of 150,000.

In this context, the new program for peace has meant an intricate struggle between a newly active government bureaucracy and the old hard-line sectors on both sides of the violence.

Valencia, the aggressive 28-year-old mayor installed by Betancur's central government last year, proudly guards a file of 250 signed statements by guerrillas accepting the amnesty. Many, he says, have been put to work in municipal programs to repair schools and build new roads, funded by part of a $240 million, four-year "rehabilitation" budget set aside for Caqueta.

Coaxed by Valencia and Florencia's archbishop, Jose Luis Serna, several of the guerrilla fronts have continued to support publicly the new reform programs and avoid new violence. And many of the guerrillas trickling into the city seem grateful for the chance to return to jobs.

"How would you like it living up in the mountains, never being able to go into the towns, suffering from hunger and cold, always having to march all night?" asked Carlos Gomez, a slender refugee from the M-19. The movement takes its name from the date of an allegedly fraudulent 1970 election.

Meanwhile, many local Army officials contemptuous of the amnesty program, have not slackened efforts to fight guerrilla groups that have called for a truce.

Other guerrilla leaders have simultaneously issued new promises of offensives and overtly sought to undermine the peace efforts. In February, even as national Peace Commission leaders were meeting with the top leadership of the Colombian Revolutionary Armed Forces, the biggest and oldest group, an autonomous front of the organization ambushed a military convoy north of Florencia, killing 11.

In the end, many community leaders fear that the civilian officials and conciliatory guerrillas will simply be crushed by the two extremes. "Caqueta will see a new round of warfare and violence, and all of those who accepted the amnesty will be caught in the center," predicted one human rights official.

Torrez, who hopes to move onto a new 240-acre farm near his old home, says that is his greatest fear. "We are all afraid, because we are out in the open," he said. "When the violence starts, the Army will come to us first, but so will the others. Then there will be no place to hide."