THE BURNED OVER DISTRICT

California farmers were hoping for Donald Trump's pie-in-the-sky promises of a better world, free of regulations and taxes when they went to the voting booth. As the reality of his ravings against "illegal immigration" become real they are now facing the loss of a major part of their work force.

As for his promises about cracking down on illegal immigrants, many assumed Mr. Trump’s pledges were mostly just talk. But two weeks into his administration, Mr. Trump has signed executive orders that have upended the country’s immigration laws. Now farmers here are deeply alarmed about what the new policies could mean for their workers, most of whom are unauthorized, and the businesses that depend on them.

“Everything’s coming so quickly,” Mr. Marchini said. “We’re not loading people into buses or deporting them, that’s not happening yet.” As he looked out over a crew of workers bent over as they rifled through muddy leaves to find purple heads of radicchio, he said that as a businessman, Mr. Trump would know that farmers had invested millions of dollars into produce that is growing right now, and that not being able to pick and sell those crops would represent huge losses for the state economy. “I’m confident that he can grasp the magnitude and the anxiety of what’s happening now.”

Mr. Trump’s immigration policies could transform California’s Central Valley, a stretch of lowlands that extends from Sacramento to Bakersfield. Approximately 70 percent of all farmworkers here are living in the United States illegally, according to researchers at University of California, Davis. The impact could reverberate throughout the valley’s precarious economy, where agriculture is by far the largest industry. With 6.5 million people living in the valley, the fields in this state bring in $35 billion a year and provide more of the nation’s food than any other state.

The consequences of a smaller immigrant work force would ripple not just through the orchards and dairies, but also to locally owned businesses, restaurants, schools and even seemingly unrelated industries, like the insurance market.

Mr. McClarty is not just concerned about his business, but also about his work force, he said. Many of them have worked for him year-round for more than a decade, making at least $11 an hour. After immigration officials audited his employee records a few years ago, he was forced to let go of dozens of employees.

“These people had been working for us for a long time, and we depended on them.”

Now he worries that a Trump administration could mandate a Homeland Security Department program called E-verify, which was aimed at stopping the use of fraudulent documents. In all but a few states, the program is voluntary and only a small fraction of businesses use it.

Farmers here have faced a persistent labor shortage for years, in part because of increased policing at the border and the rising prices charged by smugglers who help people sneak across. The once-steady stream of people coming from rural towns in southern Mexico has nearly stopped entirely. The existing field workers are aging, and many of their children find higher-paying jobs outside agriculture.

Another group that liked the sound of Trump's ravings without listening to what he was saying. Nevertheless, the looming price rise/scarcity of food resulting from the lack of labor could result in the slimming down of America.