FRESNO, Calif.—On a recent broadcast, Sam Vang engaged in the kind of on-air banter that has helped make him a global radio celebrity.
The topic: fertilizer.
"A man came by my farm and tried to sell me fertilizer, $25 per gallon," said the caller. "He said it would double my crop."
After ascertaining the salesman never showed the caller a brochure for the product, Mr. Vang declared, "Don't buy it." Then he moved on to another caller, who wanted his thoughts on her two acres of Thai chilis and why they might be yellowing on the vine.
Joel Millman/The Wall Street Journal
Mr. Vang broadcasts on KBIF-AM, a radio station in Fresno that serves local immigrants but has gained a world-wide following thanks to Web streaming. Sugar cane farmers call him from Australia. A community in French Guiana contacted him seeking advice on raising dragon fruit.
"I'm always on call," says Mr. Vang, 48 years old, who broadcasts in the Hmong language.
KBIF is an institution in California's agricultural-heavy Central Valley catering to non- English-speaking newcomers for decades, its language adjusting with each immigrant wave. On weekdays, it has shows in Vietnamese, Hmong and Lao. Weekends belong to Punjabis.
"We've broadcast in Spanish, Italian, Russian, Japanese, Armenian, Korean, Cambodian," among others, says KBIF general operations manager Tony Donato.
K.B. Brar hosts the Saturday morning Punjabi 'Auto Shop Talk' on KBIF that he makes an unabashed homage to NPR's 'Car Talk.
The surprise is how well some of the station's shows have traveled beyond Fresno. Apart from Mr. Vang and other Hmong hosts, some Punjabis on KBIF are building international audiences, too. K.B. Brar, who runs a local auto shop, hosts the Saturday morning "Auto Shop Talk" on KBIF that he makes an unabashed homage to National Public Radio's "Car Talk."
Dispensing repair advice along with current affairs, the 32-year-old says he hears from people streaming his show from as far away as Canada and India.
"My listener in North America might drive a BMW and someone in India has a Honda Accord," he says. "Either way I teach them preventive maintenance so that they can get the most out of their cars."
Joel Millman/The Wall Street Journal
KBIF rents airtime to the U.S. Department of Agriculture, chiropractors, grocers and auto mechanics. In a good year, the station, owned by Gore-Overgaard Broadcasting Inc., grosses $500,000 to $1 million in sales, says co-owner Hal Gore.
State agencies and the city of Fresno use KBIF events to educate listeners on such topics as water conservation and how to recycle used motor oil.
To draw attention to events, KBIF partners with a local merchant, who sometimes pays for farm animals to offer the winner of a raffle. The prize is "usually chickens or a pig," says Mr. Donato, KBIF's station manager, but for really big events, a sponsor will spring for a water buffalo. "To get a water buffalo will run around $1,500," he says, but it does attract a crowd.
Mr. Vang, whose day job is a USDA agronomist, is one of KBIF's biggest stars.
Born in Laos, Mr. Vang was 10 in 1974 when he left a refugee camp in Thailand to join former Hmong guerrillas resettling in California's Central Valley. He joined the USDA while completing a plant science degree from California State University, Fresno.
He began broadcasting at KBIF in 1997 with the mission of assisting Hmong and Lao-speakers. The USDA purchases airtime from KBIF for about $10,000 a year.
It is a throwback to the era when the USDA reached out to new Americans working in agriculture—at the time, mostly Latinos—who wanted advice they could receive on a transistor radio while working in the fields. These days, it is Hmong farmers.
Mr. Vang's stardom has built steadily. On a trip to Thailand as part of a USDA outreach in 2001, he recalls, "I was in the province of Nan, up north, and this old guy was staring at me. He said, 'Your voice sounds just like that man I listen to on my radio.' "
Now most mornings, Mr. Vang retrieves long voice-mail messages from overseas listeners that are left overnight on his office phone. Requests also come via email, cellphone and the postal service.
"It's just so great to know that this man, a Hmong like me, has succeeded across the ocean," says one listener, Kai Sae Lee, a 43-year-old farmer in Thailand. Mr. Lee, who raises corn some 300 miles northwest of Bangkok, says he has been a fan of Mr. Vang since 2008.
Indeed, Mr. Lee regularly bikes into town to hear Mr. Vang's show—which "airs" on a friend's personal computer after midnight.
"I learn so much," Mr. Lee says. "Like, that I can plant my corn much denser now. He increased my yield three times."
Mr. Vang says he is glad to help. He just wishes he hadn't been so free giving out his cellphone number on the air. He gets calls at all hours, he says, noting the 10-hour time difference between Thailand and Fresno.
Mr. Vang also has fans among the 25,000-strong Hmong community in the Fresno area. "We always have that radio station on, so we never miss" Mr. Vang, says Pang Eng Chang, a farmer in Fresno who follows the show on a tiny transistor radio he carries at all times.
When he isn't on the air, Mr. Vang is busy with his day job keeping farmers abreast of new products and regulations, among other things. On a recent day, he tread rows of leafy produce at a farm in Sanger, Calif., bending to assist refugee growers learning to coax incomes from bok choy, lemon grass and eggplant.
Squatting amid some women tending vines, Mr. Vang sampled Jerusalem artichoke tubers—a chewy water-chestnut substitute that is now making headway with Asian consumers. "This is the new best-seller," he says.
Later, the quacking ringtone from Mr. Vang's cellphone went unanswered as he barreled down a dusty road to another appointment. He noted the incoming caller ID.
"Another Hmong farmer," this one from northern California, said Mr. Vang. "He calls a lot. Always questions about his Brussels sprouts. And cauliflower."
Written by Joel Millman