LASHKAR GAH, Afghanistan (CNN)  -- Toiling in what is the opium capital of the world, farmers in southern Afghanistan are swapping out their poppy plants for wheat crops.



A farmer harvests wheat in a field on the outskirts of Kabul, Afghanistan, last summer.



The farmers are participating in programs sponsored by the U.S. Agency for International Development, which is offering seeds, fertilizers and improved irrigation to the region in an effort to stop poppy crops and, ultimately, the production of opium and heroin.



Observers have noticed a significant decline in the opium trade in Afghanistan, with the number of poppy-free provinces increasing from 13 in 2007 to 18 in 2008, according to a U.N. report released last year.



Opium cultivation in the country, which has 34 provinces, dropped by about 20 percent in a year, the U.N. reported in August.



"It's a challenge to deliver assistance in a war zone -- you can hear fighter jets flying above us right now," said Rory Donohoe, a USAID development officer.



"At the end of the day, what we found is successful is that we work in areas that we can work," he told CNN in a recent interview in Helmand province.



"We come to places like this demonstration farm where Afghans can come here to a safe environment, get training, pick up seeds and fertilizer, then go back to districts of their own."  Watch Afghans speak about the change in their farming practices »



Many of Afghanistan's northern and eastern provinces have already benefited from USAID alternative farming programs, which have doled out more than $22 million to nearly 210,000 Afghans to build or repair 435 miles (700 kilometers) of roads and some 2,050 miles (3,300 kilometers) of irrigation and drainage canals.



Giving Afghan farmers improved access to markets and improved irrigation is successfully weaning them away from poppy production, according to officials at USAID.



Over the years, opium and heroin -- both derivatives of the poppy -- have served as a major source of revenue for the insurgency, most notably the Taliban movement that once ruled Afghanistan.



"If you can just help the people of Afghanistan in this way, the fighting will go away," said Abdul Qadir, a farmer in Lashkar Gah.



"The Taliban and other enemies of the country will also disappear."
What do poppy plants help produce? What is agency trying to do? Who is offering seeds? What is the agency trying to do? What has been a major revenue source for the Taliban? What is the agency doing? What is USAID offering? What is used to make drugs?
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question: What do poppy plants help produce?, answer: opium and heroin | question: What is agency trying to do?, answer: stop poppy crops and, ultimately, the production of opium and heroin. | question: Who is offering seeds?, answer: U.S. Agency for International Development, | question: What is the agency trying to do?, answer: stop poppy crops and, ultimately, the production of opium and heroin. | question: What has been a major revenue source for the Taliban?, answer: opium and heroin | question: What is the agency doing?, answer: offering seeds, fertilizers and improved irrigation to the region | question: What is USAID offering?, answer: seeds, fertilizers and improved irrigation | question: What is used to make drugs?, answer: poppy crops