"Am I supposed to put this on now?"
The soldier grinned, "If you don't I will."
But then again, working with farmers in Afghanistan to help rebuild their agricultural system isn't his typical work either.
Knowles, who now lives in Hawaii, spent six months in the war-scarred nation talking with farmers about what they grow and what their needs are.
He was honored last week by USDA secretary Ed Schafer for his service in Afghanistan in 2005-06.
Hearts, minds and apricots
Knowles' travels were part of a partnership between the USDA and the U.S. Department of Defense in their campaign to "win hearts and minds" of the Afghan people.
"I think it's one of the best things we're doing in the country," Knowles said via a phone interview from his USDA office in Hawaii. "If we can help improve quality of life for farmers -- and 95 percent of the Afghan people are farmers -- we're doing something real."
Living conditions are rough. And most farmers are subsistence farmers, growing crops like wheat, potatoes, onions, tomatoes, apricots, apples and almonds.
But getting enough water for crops is a major issue.
"The country has literally been through hell for the last 20 years," Knowles said. "In 1985, the Russians bombed 50 percent of the arable land and one-third of the irrigation system. Then when the Russians left, civil war started among the ethnic groups. Then the Taliban took over."
While Knowles was in the country, he traveled with a group of soldiers and interpreters. He aided in work to construct dams, repair irrigation systems and establish nurseries of high-value trees like almonds or apricots. He also helped start storage systems.
"We found out that if the farmers there were able to store their harvest for three to six months, the price of the commodity would increase two or three times," he said.
He suggested projects like an apple juice factory and an apricot-drying factory where people could expand the sales of their crops.
Afghanistan's struggle to have a stable centralized government is just the backdrop for people working to feed their families.
"It never felt like a war zone," Knowles said. "These were just ordinary people that needed help."
The Afghan paradox: War and hospitality
The conservationist admitted to being "quite nervous" when he first headed into Afghanistan in July 2005. It probably didn't ease his mind when one of the soldiers he traveled with asked him if he'd ever fired an M4 rifle before. Or when they told him to keep the vehicle's window down in case someone would shoot at them.
"If you get fired on Mr. Knowles, we don't want to pick glass out of your face," they told him.
Despite the warnings and the occasional rocket fire at the bases where Knowles stayed, he said violence there is overstated by the media.
During his first trip to visit with Afghan farmers, Knowles saw another side of the people.
"In the first village we drove through, there were people sitting outside their shops, so close to the vehicle you could reach out and touch them," he remembered. "I caught the eye of this man wearing a turban, scowling at me. But then I smiled. His face literally transformed with a huge grin, and he put his hand over his heart."
Knowles kept smiling throughout his travels, and he saw that transformation happen again and again.
"If you study their culture, you'll see that traditionally Afghans are known as very honorable, generous and caring people," he said.
Giving and receiving
The first Afghans he really got to know were the interpreters at his camp. They immediately invited him to eat with them. They gathered in a circle, seated around a around large plate of rice and another large platter of potatoes and meat.
"Everybody ate out of the one bowl, scooping up the rice and potatoes with the flat naan bread," he said. "We became really good friends."
And meeting Afghan kids, he added, was by far the most amazing part of his trip.
"They're just dying for pens, because they need pens to go to school," Knowles said. "They're so charming, so hungry to learn. They didn't want candy; they wanted pens."
The group he was with also handed out crayons, chalkboards, solar radios and other supplies.
People told Knowles that after six months in Afghanistan he would never be the same.
"And quite honestly, I never will," he said. "It was the most fulfilling, rewarding experience of my life."
The US Secretary of Agriculture honored Knowles in Washington D.C. last week, and they also honored the memory of another USDA employee who was killed by an improvised bomb while in Afghanistan, in the same region Knowles had worked.
"It was really the saddest thing to me," Knowles said. "He was working on some of the same projects I was. He was killed on a road I had traveled many times."
From Iowa to Afghanistan
Knowles grew up in Kingsley with three sisters and a brother, then joined the U.S. Navy after high school. Following his service, he enrolled in Northwestern College in Orange City and then Iowa State University, earning a degree in agronomy.
For eight years, Knowles worked in Iowa as a soil conservation officer, then from 1988 to 2002, he worked with soil conservation in Wisconsin. His next stop: Hawaii.
"I'd always wanted to get a job in the tropics," he said. "When I was in the Navy I was on a ship in southeast Asia and I fell in love with it."
It was in Hawaii that Knowles decided to volunteer for a six-month stint in Afghanistan.
"It was really intriguing to me -- they were facing problems with erosion, heavy and widespread, and a lot of their irrigation system was destroyed," he said. "It seemed that my entire career was pointing to this. The things I'd been working with for close to 30 years were the things they needed in Afghanistan."
The USDA is still sending people to Afghanistan as well as Iraq to help people stabilize their farming economies.
"I'd still like to go back, maybe to an area where we haven't been yet -- like the unstable part along the Pakistan border," Knowles said. "I feel like I have unfinished business."