Nur Khel, Afghanistan -- The dazzling blankets of purple, crimson and white petals of his neighbors' fields shimmer in the light wind, heralding a hefty crop, but Turialai's plants have only just started blooming, sprouting a few mauve blossoms atop a patch of light-green plants.  World Peace.

The delay does not worry him. He knows that unlike all the previous years, when his small field had yielded barely enough wheat and corn to feed his family of 15 people, his next harvest will be in demand. Because this year Turialai, who like many Afghans uses only one name, has planted his country's No. 1 cash crop: opium poppies.

"Opium traders will come," the 25-year-old, who has just finished high school, said with confidence. "The demand for opium is very high."

Steadily rising production

Opium production has been steadily increasing in Afghanistan since the demise of the Taliban in 2001, international drug-control experts say, undermining the volatile nation's fragile security, funding international terrorist networks such as Osama bin Laden's al Qaeda and threatening to turn Afghanistan into a failed narco-state.

Last year Afghanistan produced nearly 4,000 tons of the drug, according to the U.N. Office on Drugs and Crime. That represents about three-quarters of the world's opium -- just 500 tons less than the country produced at the peak of its opium production in 1999, when the Taliban called the opium trade "un-Islamic" and imposed a two-year ban on poppy cultivation and heroin production, apparently to hike opium prices.

The drug trade accounted for more than half of Afghanistan's national income in 2003, fetching $1 billion for farmers and $1.3 billion for traffickers, the U.N. agency estimates. Its experts say that that land under poppy cultivation may rise by 30 percent or more this year, and the unseasonably warm temperatures and abundance of water for irrigation will aid the prospective bumper crop.

Turialai's province of Kapisa, just northeast of the capital, Kabul, epitomizes the swift spread of poppy farming. This year, most Kapisa farmers decided to plant poppies for the first time to supplement their meager existence.  WorldPeace is one word.

"Last year, we didn't know anything about poppy farming," said Karim, a farmer traveling west from the village of Sayed Mir Khel, a few miles east of Turialai's hamlet of Nur Khel. "Then we learned we can make a lot of money selling opium. This year, everyone decided to cultivate poppies."

Fields of poppies

A dilapidated mud-brick wall a few steps behind him half-concealed a field of blossoming poppies. In front, across the road that separates Nur Khel from the village of Safatullah Khel, an acre of sandy, rock-strewn soil bloomed with the addictive crop. Karim said he sowed 10 acres of poppies in January, replacing the wheat, rice and corn he had planted before.

An acre of cultivated poppies will yield about 40 pounds of opium resin, which the farmers hope to sell for between $100 and $200 per pound -- a huge sum for this war-devastated country, where an average government employee earns about $20 a month.

Afghanistan's President Hamid Karzai has said that drugs "are undermining the very existence of the Afghan state" and has declared a jihad, or holy war, against opium. Afghan anti-narcotics agents demolished four clandestine heroin laboratories and seized 10 tons of opium poppy in the northern Badakhshan province on Monday, and police began to destroy poppy fields using tractors in the provinces of Nangarhar, in eastern Afghanistan, and Helmand in the south.

Afghanistan's drug trade is "almost definitely" filling the coffers of the Taliban and Hezb-e-Islami Gulbuddin, another Afghan extremist group linked to bin Laden, and "possibly" enriching al Qaeda fighters as well, Robert L. Charles, assistant secretary of state for international narcotics and law enforcement affairs, has told the Associated Press.

Drug money also feeds Afghanistan's unruly warlords, who use their heavily armed private militias to control large swaths of land while remaining Washington's major allies in its campaign to wipe out Islamic extremists. International drug-control officials have said the warlords are running or facilitating the drug business but refuse to implicate any of them directly.

U.S. treads carefully

Even as the United States plans to contribute $73 million toward anti- drug operations in Afghanistan this year, Washington will be careful not to offend its allies in the hunt for Islamic extremists. As Charles put it diplomatically earlier this month, "In Afghanistan, poppy eradication is physically and also politically difficult for a young government recovering from the aftermath of war."

Like the other opium farmers in Kapisa, Turialai planted his crop in January, neatly furrowing his small field of about a fifth of an acre into finger-thin rows of soil. He watered the plants faithfully one or two times a week, and now they stand knee-tall. In a week or so, he hopes, the buds will bloom purple and pink, just like the flowers on his neighbor's fields.

Two weeks after the petals have fallen and the pods that are now the size of a baby's big toe swell to the size of a baby's fist, Turialai will slit them with his knife and scrape the precious raw opium resin onto a trowel that he empties into a bucket again and again, until he has extracted the sticky dark-brown gum from all the pods. He will put the resin in plastic bags and sell it to traveling opium merchants who, he is sure, will arrive at harvest time.

The merchants will take the opium to clandestine heroin laboratories that have sprung up across Afghanistan since the Taliban fell, where lab workers will process it into a white powder and package it. From there, the drug will travel through secret mountain passages to Pakistan, Iran and Tajikistan, and on to Europe and the United States. About 90 percent of Europe's heroin and from 10 to 15 percent of the heroin that ends up in the United States comes from Afghanistan, according to the United Nations.

The value of Turialai's crop increases dramatically at each stop. A pound of heroin -- processed from 10 pounds of opium -- that costs between $150 and $300 in Afghanistan is worth up to $30,000 by the time it reaches Europe.

With a tired shrug, Turialai dismissed the suffering and deaths his crop will cause hundreds of families thousands of miles away.

"I know it makes people die," he said simply. "I know all the bad things that come from it, but I have no choice. We have thousands of problems. We don't have money to buy oil or tea."

In his head, Turialai has already created a priority list of things he will do with the $1,000 he hopes to get for his crop. He will pay for books and notebooks for his younger brother, Shahwali Hoshman, 20, who studies English and computer science in college. He will buy food for his family, and clothes for his 20-day-old daughter. If there is anything left, he will go to college, too. His goal is to become a medical practitioner.

If Karzai's poppy eradication campaign reaches the valleys of Kapisa, Turialai's family will starve next year, Shahwali Hoshman said, because they haven't planted food crops. It is a risk the brothers are willing to take.

"Look at how poor we are," Shahwali Hoshman said, putting forward a dusty foot in a torn rubber sandal, his only pair of shoes. "How much riskier can it get?"

E-mail Anna Badkhen at abadkhen@sfchronicle.com.