“From the farmers on, there’s collusion,” said Mr. Lemahieu, referring to the payments the farmers and the traffickers make to protect the poppy crops.

Though poppy cultivation continues to flourish elsewhere, NATO has shown real progress in the Helmand River Valley in the area now called the food zone. Here, the poppy crop has been eliminated almost entirely, and the Taliban have had to relinquish their hold.

In the irrigated areas of Nad Ali, the British, who had military responsibility for Helmand until last year, distributed high-quality wheat seed to spur farmers to stop planting poppies. The effort worked best among farmers who had well-irrigated land and were able to grow enough wheat that they could invest in secondary businesses in towns to augment their income, according to David Mansfield, a researcher at Tufts University who has tracked the rural livelihoods in Helmand Province for more than a decade and recently published an exhaustive study of the province’s rural economy.

Helmand’s governor, Gulab Mangal, coupled the wheat seed distribution program with aggressive poppy eradication in the food zone, where Nakilabad Kalay is. By the second year, there were impressive results: a 33 percent reduction in poppy cultivation in the food zone. But that trend diminished sharply in subsequent years, with only a 7 percent reduction in 2010 and a 3 percent reduction in 2011, according to statistics from the provincial reconstruction team in Helmand, suggesting that the alternative crop program’s effectiveness may have reached its limit.

Image Credit... The New York Times

While wheat pays relatively well, selling it can be a problem, several farmers in Nad Ali said. That is even more true of cotton. Farmers have complained that the government’s cotton mill often either is not working or is slow to pay farmers for their crops. Moreover, Afghan cotton cannot compete with cheaper Pakistani cotton, they say.

For poorer farmers, many of whom say they were sharecroppers when they worked land in the food zone, moving to the desert to grow poppies has meant they can afford to buy land since it is cheap, and they can feed their families better because they can earn more. Mr. Mansfield’s study notes most farmers in the desert areas can afford meat more often than they could as sharecroppers growing legitimate crops in the food zone and can afford to marry off their children, an expensive undertaking in Afghanistan.