BERKELEY -- The portion of California agricultural crop workers who are not authorized to work legally in the United States jumped from nine percent in 1990-91 to 43 percent in 1995-97, according to researchers at the University of California, Berkeley, who are releasing a report on the findings today (Tuesday, Dec. 15).

The report - "Who Works on California Farms?" - analyzes California data from the 1995-97 National Agricultural Workers Survey conducted by the U.S. Department of Labor.

"It's as good a snapshot as we can get of today's seasonal agricultural work force," said Howard Rosenberg, a UC Berkeley cooperative extension specialist and lead author on the new UC Division of Agriculture and Natural Resources publication.

Besides employment eligibility, the new report reveals that the average age of seasonal farm workers in California is 33 years. About 61 percent are married, 56 percent have children and 18 percent are women. Typically, they are employed almost half the year in seasonal farm work, and about three-fourths earned less than $10,000 annually.

Most - 91 percent - are natives of Mexico, and the number of workers who have lived in this country only a short time, less than three years, more than doubled since 1990 from 12 percent to 26 percent.

The new numbers also reveal how time has eroded effects of an earlier U.S. immigrant amnesty program. This program - the Special Agricultural Worker Program, part of the Immigration Reform and Control Act of 1986 - provided legal resident status to about one million agricultural workers in the United States. It was intended to mitigate a requirement to hire only authorized workers, while recognizing contributions of many workers "who had been here illegally doing field work to grow and harvest the nation's food and fiber," said Rosenberg.

"The Special Agricultural Worker Program didn't fill the gap long term," said Rosenberg. "The program in no way bound people to continue as agricultural workers. They were entitled to walk - to find employment in any industry at all - and surely many have. There has been a slow attrition from agriculture of people who were legalized under the program. It has been gradual, but cumulatively substantial."

Since the amnesty program closed, "people who have immigrated illegally across our southern border have remained ineligible for legal employment," said Rosenberg.

But growers and other employers have hired large numbers of these newcomers, even though workers are required to show valid identification and proof of work eligibility prior to employment. Most acquire and present false credentials.

"I show my beautiful new driver's license and Social Security card that I bought at the flea market for $40 to the guy I want to work for. There's a lot of that going on," said Rosenberg.

Most jobs held by these workers are intermittent and involve difficult work for which pay is low, he said.

"The typical pay for strawberry picking, grape vine pruning or peach thinning, for example, is less than for automobile assembly work, even though these jobs all require judgment, manual skills and stamina," said Rosenberg. "The average wage rate on farms is little more than half that in manufacturing."

He said the news that growing numbers of their workers are actually unauthorized will not surprise growers, many of whom believe even the new UC report numbers are low.

"You know that anyone who looks official and is taking data will scare off people concerned about their status here . . . Some growers I have talked to estimate the number of unauthorized workers locally to be as high as 70 or 80 percent," said Rosenberg.

These farmers see government agencies doing more to spot unauthorized employees, he said, and fear further crackdowns could happen at any time.

"Facing as many environmental and man-made risks as they do, farmers tend to worry a lot," Rosenberg said. "They have all their potential income out there in the field, and they know if they can't cultivate or harvest a perishable crop when it's ready, they stand to lose a whole year's paycheck."

But, Rosenberg points out, people are afraid on both sides of the employment picture. While farmers fear for their crops, unauthorized workers may be terrified of discovery, especially if solely supporting their family.

"And if they're afraid enough to dodge the survey interviewer," said Rosenberg, "you can bet they are also reluctant to exercise their rights and protections under the law."