Highly educated and well-versed in international agriculture, UC Cooperative Extension farm advisor for Imperial and Riverside counties, Juan Guerrero, said he never stopped being a "plow jockey." After 25 years of working with desert ranchers and farmers, Guerrero retired in June.

"I always tried to maintain a sense of what commercial agriculture is really all about," he said. "It's not just about statistics gleaned from small research plots, it's about lifestyle and making money, a way of life and paying the bills."

Guerrero was born in San Antonio, Texas, and during childhood worked on the family farm. At Texas A&M University, he earned a bachelor's degree in animal science in 1970, then went overseas with the Peace Corps to work with subsistence farmers and large-scale commercial farmers in Paraguay and Peru.

Returning to Texas five years later, Guerrero continued his education at Texas A&M, earning a master's degree in agriculture in 1977 and a doctorate in animal science in 1980.

Upon graduation, Guerrero took a position with Texas A&M, funded by a grant from the United States Agency for International Development, to do extension work in Paraguay. The trip marked what would become a career-long association with USAID in which Guerrero traveled throughout the world to share expertise and learn from farmers in countries including China, Mongolia, Kazakhstan, Egypt, Uganda and El Salvador. Guerrero's work with USAID resulted in letters of commendation from presidents George W. Bush and Barack Obama.

In 1984, Guerrero accepted the position with the University of California serving growers working California's southernmost desert farmland.

His research program focused on alfalfa. One particularly successful project quantified the benefits of using sheep for weed control in alfalfa. He determined that grazing sheep in alfalfa fields was just as effective as spraying chemical herbicides. In another project, grazing lambs were compared to insecticides for insect control in winter alfalfa. In this two-year trial, lambs provided insect control as effectively as insecticides. The research results benefited the area's alfalfa growers and the sheep industry.

"Sheep had been used for weed control longer than I've been here, but we were able to put the numbers to it," Guerrero said.

Guerrero worked closely with UC Davis Animal Science specialists and with California feedlot managers to develop a quality assurance program and conducted feedlot employee training at the ranchers' request to teach methods they could use to ensure beef quality and wholesomeness.

Researchers and students at the Universidad Autónoma de Baja California, a public university in Mexicali, Mexico, were also research and extension collaborators with Guerrero. In 2005, UC officials signed a memorandum of understanding with the Universidad Autónoma to formalize the relationship. Over the years, Guerrero mentored five Mexican doctoral students and more than a dozen master's degree students when they did their research at the UC Desert Research and Extension Center in Holtville, Calif. The 255-acre desert research center and UC Cooperative Extension headquarters are just 15 miles from the Calexico-Mexicali international border.

At the Desert REC, Guerrero conducted research on a variety of animal feed crops to determine their suitability for desert cultivation. One of them was kleingrass, a drought-tolerant African grass that thrives in hot climates.

"It gets really hot here," Guerrero said. "We had to find pasture varieties than can sustain the heat and do well."

A group of Japanese visitors, impressed by Guerrero's kleingrass plots at the research center, got together with a local grower to arrange for the hay to be grown in the area for Japan's dairy industry.

"Now there are 40,000 to 50,000 acres of kleingrass growing up and down the length of the Colorado River," Guerrero said. "The hay is baled and exported to Japan, giving our local growers an excellent market opportunity."

Guerrero plans to continue his work with USAID during retirement. Next month he travels to Lebanon and he anticipates more travels overseas to teach growers basic agricultural know-how.

"Their education needs are at a very basic level -- how to use fertilizer, how to mix feeds for animals, how to drive a tractor on a curve. It's not classroom stuff. I'll be teaching farmers the basics. That's what I've always done," he said.

He also hopes to move back to his beloved home state of Texas one day.

"I'm a diehard Tejano, 100 percent," Guerrero said. "As soon as the economy straightens out, in two or three years, my wife and I plan to go home and live along the Texas-Mexico border."