They're talking mostly about two water intensive crops; almond trees and grapevines, two crops no one needs to survive. It sucks that I have to breath that stuff all day today when they're asked to grind it up instead.
The current model of farming in California is ultimately doomed; much of the groundwater depleted over the past century cannot be replenished as the ground has subsided and compacted itself after the water was pumped out. Basically the entire Central Valley sank by about 16 feet between 1920-1970 (https://www.usgs.gov/centers/land-subsidence-in-california/s...). Data since then is spotty because we basically stopped monitoring it.