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The machine that revolutionized a harvest

Issue Date: March 15, 2006
Kathy Coatney

A large, slow-moving piece of agricultural equipment that helped revolutionize the processing tomato sector in California has been given historical landmark designation by the American Society of Agricultural and Biological Engineers.

The UC-Blackwelder tomato harvester, developed at the University of California, Davis, in 1949, helped to usher in mechanization that proved vital in the growth of California's tomato-growing business. Partly because of this piece of equipment, California now produces 95 percent of the processing tomatoes grown in the United States.

UC agricultural engineer Coby Lorenzen and UC vegetable crops researcher Jack Hanna collaborated to develop not only the tomato harvester, but also a tomato variety that would survive mechanical harvest.

The tomato harvester was put into use in the mid-1960s during the mechanization boom in agriculture. Its use prompted a backlash, though, by people who believed that mechanization was eliminating jobs.

"USDA (U.S. Department of Agriculture), which had funded a lot of work on mechanization, essentially withdrew its support," said Bruce Hartsough, professor and chair of the Department of Biological and Agricultural Engineering at UC Davis. California growers found that conversion to use of the mechanical tomato harvester was complicated, Hartsough observed.

"It was not as easy as just taking a harvester and putting it out in their existing field with the existing varieties. They had to change what they were growing, their irrigation, fertilization—all sorts of things," Hartsough said.

Butte County farmer Les Heringer used one of the first tomato harvesters. "We'd harvest in the daytime, and then we'd work all night putting it back together," Heringer said.

Heringer was among the growers who felt the need for the mechanical harvester to become operational.

"It was a case of putting that machine together some way, somehow. That's the reason we worked day and night on that thing to put her together, and get her out in the field, and see if we couldn't make her work. And we did," Heringer said.

Heringer believes without question that the mechanical harvester saved the California tomato industry.

Despite the initial complexities, California was well suited to these new varieties because of the state's dry climate during the harvest season, Hartsough said. "In a lot of areas of the U.S., it just wasn't possible to get a machine in the field when they wanted to harvest the tomatoes."

Nearly all of California's tomato crop was converted to machine harvest within about five years, Hartsough said. That kind of rapid change isn't the norm, he added, noting that the changeover occurred much more slowly in other parts of the country and the rest of the world.

"Not only did it (tomato harvesting) change rapidly in California, but the industry expanded here—essentially doubled in size. In the rest of the country, it kind of dropped down because they couldn't compete with the lower costs of harvesting here."

Heringer agreed, saying, "We just about conquered the whole tomato industry when we got those machines running in two or three years."

An original UC-Blackwelder harvester is being reconditioned by the UC Davis Antique Mechanics Club, a student group that collects, repairs and restores antique farm equipment. Victor Duraj, the volunteer collection manager, said that the antique farm equipment collection started in the 1960s, then took on a more official status when the student club was formed in 1971.

Pieces of equipment from the antique collection are put on display in the annual Picnic Day Parade on the UC Davis campus. Items from the collection also are used in classes ranging from agricultural practices to social science, Duraj said.

The Antique Mechanics Club, which is not funded or staffed by the university, depends on donations and volunteers. Farmers throughout California have contributed aging equipment of historical value, encouraged by the club's Web site at

Hartsough and Duraj said they believe that preservation of antique equipment is important because it can help inspire future innovations.

"Our equipment is sometimes accessed for working on new problems," Duraj said. "Sometimes a hands-on look at something old helps spur a new idea."

That's how the tomato harvester was developed.

"It pulled in elements from a lot of different areas. The device for separating the tomatoes from the vine once the plant had been picked up onto the machine was essentially like a straw walker on a combine," Hartsough said.

"There is some engineering that is all brand-new," Duraj acknowledged. But he said that many engineering concepts involve adapting or modifying principles used in existing equipment.

Hartsough agreed that the invention process doesn't rely on entirely new ideas.

"It's taking ideas and applying them in a new area, mostly," Hartsough said.

(Kathy Coatney is a reporter in Corning. She may be contacted at

Permission for use is granted, however, credit must be made to the California Farm Bureau Federation when reprinting this item.

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