For as long as anyone can remember, there was no need for paper money in this remote corner of the Hindu Kush. The common currency was what grew in everyone's backyard — opium.

When children felt like buying candy, they ran into their father's fields and returned with a few grams of opium folded inside a leaf. Their mothers collected it in plastic bags, trading 18 grams for a meter of fabric or two liters of cooking oil. Even a visit to the barbershop could be settled in opium.

But the economy of this village sputtered to a halt last year when the government began aggressively enforcing a ban on opium production. Villagers were not allowed to plant their only cash crop. Now shops are empty and farmers are in debt, as entire communities spiral into poverty.

Opium is one of the biggest problems facing this troubled country, because it is deeply woven into the fabric of daily life as well as into the economics of insurgency. Afghanistan supplies 93 percent of the world's opium, and it is one of the main sources of funding for the growing Taliban movement.

Yet the government ban on opium is working at best unevenly. In areas of the country under Taliban control, opium production is going strong. In government-held areas like Shahran, it has gone down drastically, but at the cost of the livelihood of hundreds of thousands of people. Their anger is imperiling government support in one of the few areas of the country that has resisted the Taliban's advance.

"Now we don't even have 10 Afghanis ($0.25) to give our children to buy bubble gum," says opium farmer Abdul Hay. "Before they would go into the field and collect the money themselves."

Two years ago, opium, the raw ingredient used to make heroin, grew on nearly half a million acres in Afghanistan. The harvest was worth about $4 billion, or equal to nearly half the country's GDP in 2007. As much as a tenth — almost half a billion dollars — went to local strongmen, including the Taliban, according to the U.N. Office on Drugs and Crime.

Under intense international pressure, the government redoubled its effort to crack down on opium farmers. By last year, the number of acres planted with poppy had dropped by a fifth, yet the Taliban's finances remained largely untouched. Ninety-eight percent of Afghanistan's opium is now grown in just seven of the country's 34 provinces — all areas under partial or total Taliban control.

Opium was so entrenched in Badakshan province, where Shahran is located, that it is said Marco Polo sampled it when he passed through in the 13th century. Until recently, the sloping mountain faces were awash with pink, purple and magenta poppies, nodding in the wind. But in the past year, poppy production has gone down 95 percent.

The villagers here held a meeting and decided two years ago not to plant opium, after government radio messages warned that poppy fields would be destroyed and opium growers jailed. Posters distributed throughout the area showed a man with his hands bound by the stem of the opium poppy.

The villagers say they did as the government told them, and planted their fields with wheat, barley, mustard and melons. But these crops need more care than the tough opium poppy, which will bloom with little water or fertilizer.

Most of the wheat fields yielded little because the farmers couldn't afford to fertilize the land. Even where yields were decent, farmers say they could have earned between two and 10 times more by planting the same land with opium.

"See this mustard? It can take care of my family for one month," says 25-year-old farmer Abdul Saboor, pulling up a shoot of the green plant and snapping it open with his teeth. "When we planted opium in this same plot, it took care of all our expenses for an entire year."

The hole in the economy is swallowing up the community, from the farmer to the turbaned shopkeepers whose scales used for weighing opium now sit idle.

Every month, shopkeeper Abdul Ahmed used to bring $20,000 worth of goods to sell in the bazaar. It's been four months since his last truckload, and he has only sold $1,000. Ahmed is one of 40 traders left; there used to be 400.

"We open in the morning and go back at night. No money comes in. No one buys anything," says Ahmed. "There is no money left in this village. Opium is the only income we had."

Villagers say desperation is pushing hundreds to immigrate to neighboring Iran, where they work as day laborers. Farmers throughout the region are also sinking deeply into debt. They borrow money to buy staples like rice and oil, which they used to buy with opium. They also take loans to buy seeds and fertilizer and to rent donkeys to take the wheat to market — an expense opium did not bring because all the local shops accepted it as legal tender.

On a hill flanking the highway in Argu District, a 4-hour drive southeast of here, a thin farmer is bent over cutting wheat with a hand-held sickle. Abdul Mahin says he is several hundred dollars in debt to the man who sold him fertilizer.

"If we plant two bags of wheat, then we'll have just enough money to buy the seeds to plant another two bags of wheat," says the gray-bearded farmer. "We're going backwards. Of course we're angry at the government."

A small number of farmers in other towns are planting opium despite the ban. Most are seeing their fields destroyed, as government agents intensify patrols.

Farmer Abdulhamid, 55, says he has only rain-fed land, and none of it is irrigated. So he can't grow wheat and barley with much success. Unless the government helps, he says, he will have to plant opium again.

"We are getting poorer day by day," says Abdulhamid, in the village of Pengani. "What should I do? Kill my children so that I don't have to feed them?"

When farmers were asked to stop planting, they were promised help from the government. Badakshan is set to receive $1,000 for each hectare (roughly 2 1/2 acres) of land freed of poppies — some $10 million this year. It's being used to build three clinics and three schools, pave a major road and rebuild six fallen bridges.

Farmers say a distant clinic or bridge is not going to feed their children. But counternarcotics experts and government officials respond that the opium ban is necessary.

"These poor farmers are going to get stepped on and get hurt in this effort," says former Drug Enforcement Agency official Doug Wankel, who organized the U.S. counternarcotics effort here in 2003. "But it's a pain that has to be endured for the good of the masses."

"In the U.S. and the U.K., when people do an illegal activity, the police stops them, right? This is an illegal act, so we need to stop it in order to enforce the rule of law," says Zalmai Afzali, a spokesman for the Ministry of Counternarcotics. He also notes the link to the insurgency: "I try to explain to the farmer that cultivates poppy that he is buying a coffin for his child."

Yet the poverty created by getting rid of opium may be stoking terrorism. Nangahar — which became poppy free last year and is held up as an example of government control — has seen a rapid increase in extremism, according to a field study by David Mansfield, counternarcotics consultant for the U.N. and the World Bank.

By April last year, the province rescinded agreements to limit the movement of anti-government groups on its border with Pakistan. By July, these groups were believed to have set up bases in four districts next to Pakistan. By September, they were attacking government buildings. And by October, there were Taliban checkpoints.

Also, the crackdown in the country's far north is unlikely to stop the flow of opium and money to the Taliban in the south. In Zabul — the home province of Taliban spiritual chief Mullah Omar — poppy production grew by 45 percent last year.

Helmand province, a Taliban stronghold, grew so much opium last year that if it was a separate country, it would rank as the world's top opium producer, according to Gretchen Peters, author of "Seeds of Terror," on how the Taliban is bankrolling itself through drug smuggling. Peters says the Taliban's video messages now talk about securing smuggling routes and protecting poppy plantations.

Poppy fields in Taliban areas are so dangerous that eradication teams comb them for bombs before trying to destroy them. Last year 78 government agents were killed trying to destroy fields in the south. By contrast, the worst they faced in Badakshan was crying farmers.

Zainuddin, the head security officer for Darayim district in Badakshan, says he feels awful every time he uproots a poppy field.

"Sometimes I cry as I am hitting the poppies," says Zainuddin, who like many Afghans goes by a single name. "Because I know these are poor people and I am taking away the only thing they have."

Over the past month, dozens of fields have been destroyed in the mountains of Badakshan. Nasrullah, a 35-year-old farmer, planted three small plots of white-and-violet poppies inside a hill of wheat, hoping the taller crop would hide the illegal blossoms.

He stood in silence on a recent morning as nine police officers crossed a small gulch and climbed the hill. They assaulted his crop, hitting the flowers with long sticks until they fell to the ground. He put his face in his hands.

"I didn't plant this for my own pleasure," he says. "I planted this so that my family could eat. All the rest of this is worth nothing," he says, waving at the wheat. "The choice I have to make now is either kill myself. Or leave the country."