LOS RÍOS, Colombia — Every three months or so, Javier Tupaz, a father of six, heads downhill from his clapboard home to work in his cocaine laboratory.
Under a black tent in the jungle, he shovels coca leaves into a giant vat with gasoline, then adds cement powder — the first steps in his cocaine recipe.
Like everyone in his village, Mr. Tupaz depends on coca for cash and has survived decades of war here in Colombia. He churned out his product during the seemingly endless conflict between the rebels and the government, which tried many times to destroy his coca plants. He simply replanted.
But there is one thing that Mr. Tupaz says his crops may not survive: peace.
The peace deal signed late last year between the government and the main rebel group — the Revolutionary Armed Forces of Colombia, known as the FARC — was never just about ending the Americas’ longest-running conflict.
The Colombian government also sees peace as its biggest chance in decades to uproot the rebel-controlled drug trade and replace it with crops that are legal, though admittedly less lucrative.
“We celebrated the deal; after all, the conflict was over,” Mr. Tupaz said next to one of his large drug vats. “But on the other hand, the FARC had control here — you could grow coca, have a lab, and you were protected.”
Peace means that soldiers no longer have to shoot their way into rebel-held territory to pull up coca plants or dismantle drug labs. Now the FARC, which formally disarmed last month, is joining forces with the government to wean farmers off coca — one of the first collaborations ever between the old enemies.
Outside Mr. Tupaz’s village, Los Ríos, the rebels now appear in civilian clothes alongside government officials, selling farmers on crops like black pepper and heart of palm.
“Without the war with the FARC we have a great opportunity ahead,” said Vice President Óscar Naranjo, a retired general who spent much of his career fighting the rebels.
There is a clear urgency to the effort. Even as the government and the FARC were negotiating peace, coca cultivation in Colombia soared last year, with a record amount of land being used to grow the crop, according to the White House Office of National Drug Control Policy.
Now, as part of its reconstruction plan for Colombia’s war-ravaged countryside, the government is promising money to the first 50,000 coca-growing families that take the offer: a monthly payment of about $325 for the first year that farmers give up coca, followed by subsidies to plant new crops and education on how to grow them.
But with the carrot comes sticks, General Naranjo warned.
“Not everyone will want to substitute their crops,” particularly those with deep ties to the drug industry, he said. “And for them, there will be forced, manual eradication.”
From the tiny plot near his village, Mr. Tupaz says he has seen this before.
He recalls the early 2000s, when the government gave every family here two cows to ease them off coca production, which led to plummeting prices for cattle when people sold them. Or, when officials came with a plan to grow vanilla, which failed because no one knew how to grow vanilla in Los Ríos.
There was even the time in 2010, after so many fumigations of his coca plants, that Mr. Tupaz simply gave up on drug cultivation and trekked down a muddy path to the bank in town, taking out a loan to plant two acres of cacao, which is used to make chocolate.
“They were just this size when they were sprayed, too,” he said, raising his hand a few feet off the ground as he recounted how military planes dropped chemicals that ended up killing his legal crops.
The fumigations were eventually halted in 2015 because the herbicide used, glyphosate, was linked to cancer by the World Health Organization. When the spraying stopped, American officials have argued, coca cultivation increased. (Colombian officials dispute that conclusion, citing other factors, like the falling price of gold in recent years, that made coca farming more attractive.)
For many rural Colombians, the issue is one of simple math: The coca plant used to make cocaine is far more profitable than anything else that could be grown here.
Los Ríos, with 32 families, sits more than an hour’s hike through mud and rivers, cut off from hospitals, markets and virtually every industry except drugs. Its residents say peacetime leaves them with a choice between the criminality of coca and the even deeper poverty they would face by planting something else.
“We have accepted it: We will earn less with other crops,” said Edward Cuaran, 23, a coca grower who returned to Los Ríos, despite having attained a university degree, because he could not find work. “But what choice is there?”
Already, coca prices have dropped because so much coca was planted and fewer rebels are involved in the drug trade, leaving many growers without a buyer.
Meanwhile, the government has taken marijuana, long trafficked by rebels, and legalized it for medical production, largely by corporations. Few licenses have been granted so far, and many small farmers complain that they have been shut out.
That has left difficult choices in places like Corinto, a town 300 miles north of Los Ríos, at the foot of mountains threaded with marijuana bushes and the light bulbs they grow under.
At a meeting of dozens of farmers, a woman opened with the Lord’s Prayer and urged God to “to help us all substitute illegal crops with legal ones.” Edward García, the mayor, outlined a government package for townspeople on a whiteboard.
“They won’t wait forever for us to sign up,” he said, warning that the military was already patrolling the edges of the town.
A few farmers have made a successful switch. Near the border with Ecuador, Pablo Ángel Cuaran hacked down a tiny palm tree with a machete, then sliced open the trunk to reveal its juicy center: heart of palm, which he started cultivating a decade ago.
He and other members of a farmers cooperative all plant the crop now, and bargained with the local government to bring them electricity in exchange for their uprooting coca plants. The legal crops stretch out for 200 acres of flatlands that include a mass grave site where paramilitary fighters buried scores of victims.
A tall cross marks the site, now overgrown with a new crop of palm trees. When Mr. Cuaran was a child and coca grew in the fields, a man in a white coat could be seen sometimes at a bend in the road, dismembering bodies with a machete, he recalled.
“You had a lot of money then, but you were never calm,” Mr. Cuaran said.
A few hours’ drive away, 500 families have signed up for the new government crop substitution program in La Carmelita, a region with a dozen villages next to a rebel demobilization camp. Last month, they began pulling up their coca plants, said Aldemar Yandar, the local coordinator of the program.
“People will soon see what their neighbor is doing, and they will want to copy it,” Mr. Yandar said.
But the draw of the coca leaf is always near. Near La Carmelita, a government-sponsored sugar cane processing plant had dropped to a dozen workers, from more than 30 a year ago. Most of the employees had left to harvest coca leaf and the processing plant could not find anyone to take their places, workers said.
“We are surrounded by coca fields,” said Alirio Hernández, a leader in the local processors’ association. “They pay double.”
General Naranjo, the vice president, remained upbeat. Because the government was no longer focused on war with the rebels, he said, it could finally build the roads and infrastructure to create markets for legal crops, while delivering a finishing blow to the remaining drug traffickers.
But he acknowledged the program might not work for everyone, like those in very small villages not connected to roads, or those who have settled as squatters in national parks, where coca growing exploded in recent years.
“These families will have to relocate,” the vice president said.
Campo Elías Chagua, 50, a coca farmer outside a town called La Hormiga, hopes he will not have to move.
On a recent morning, Mr. Chagua trudged through a dense rain forest of vines and tropical birds, which suddenly opened up to his coca farm. He and his 27-year-old son spent the day harvesting the coca bushes as a fellow coca farmer, Arnulio Quiñones, looked on.
“The FARC would keep order,” said Mr. Chagua’s wife, Mariana Narváez, remembering the old days.
But, they wondered, would the government? There was still no electricity here, no running water. And now officials were asking them to give up their coca.
“We could go back to violence if the government doesn’t hold up its end of the deal on this,” Mr. Chagua said.
That day, they visited the lab of a neighbor, who was processing cocaine paste with help of a hired hand. The smell of gasoline and raw leaves hung in the air.
“He just wouldn’t survive off of black pepper,” Mr. Quiñones said.