Valley Center, Calif. — On an organic farm here in avocado country, a group of young Marines, veterans and Army reservists listened intently to an old hand from the front lines.

“Think of it in military terms,” he told the young recruits, some just back from Iraq or Afghanistan. “It’s a matter of survival, an uphill battle. You have to think everything is against you and hope to stay alive.”

About 45 percent of the military comes from rural communities, compared with one-sixth of the total population, according to the Carsey Institute at the University of New Hampshire. In 2009, the Agriculture Department began offering low-interest loans in its campaign to add 100,000 farmers to the nation’s ranks each year.

Helping Soldiers Trade Their Swords for Plows