California’s San Joaquin Valley, from Stockton in the north to Arvin in the south, is 234 miles long and 130 miles wide. If you drive there from the Bay Area, in less than an hour the temperature will go from 57 to 97 degrees. It will keep rising. The radio stations are predominantly Spanish: ranchera music, boleros, corridos, ballads of spurned love, and the distinctive norteño sound—percussive, driving, no brass. On the English-language station an indignant voice advises listeners to be mentally vigilant against “sitcoms, news reports,” the entire panoply of “mainstream media because it’s all the same skank, it’s all from one cesspool, their snakish agenda for a one-world order.” The country music summer hit is called “Take a Drunk Girl Home.”

The Valley is flat, under a constant cloud of dust, smog, pesticides, and smoke. The smog is from Bay Area traffic carried in by the wind, the pesticides from the millions of pounds of chemicals poured onto the land every year, the smoke from the wildfires that burn to the north and get trapped in the Valley, pushed to the ground by the heat. The cloud is kept there by the Sierra Nevada to the east, the Coast Ranges to the west, and the Tehachapi Mountains to the south, which the Fresno-based writer Mark Arax calls “our Mason-Dixon Line,” because it marks the Valley’s physical and psychological separation from the cosmopolitan culture of Southern California and Los Angeles. The city of Bakersfield and the area around it, on the southern edge of the Valley, has the worst air quality in the United States.

Measured by yearly production, the San Joaquin Valley is one of the highest-value stretches of farmland in the country, and is dominated by large growers who preside over a labor force of migrant workers in a way that has not changed much since Carey McWilliams described it in his 1939 book, Factories in the Fields. Arax likens it to a Central American country. “It’s the poorest part of California,” he told me. “There’s almost no middle class. To find its equivalent in the United States you’d have to go to Appalachia or the borderlands of Texas.”

Raisins, table grapes, pistachios, almonds, tomatoes, stone fruits, garlic, and cabbage are some of the crops of the Valley. The clementines that we buy in netted bags at the supermarket are grown here, as are the pomegranates that make the juice we are told protects us from cancer. The revenue from all the crops harvested here and elsewhere in California is $47 billion a year, more than double that of Iowa, the next-biggest agricultural state. Most of this revenue benefits a few hundred families, some with as many as 20,000 or even 40,000 acres of land.

Plantations on the west side of the Valley are so huge…