Seems like prioritizing the common good is in line with big aggro if we don't care about the independent farmers this could impact.

The state should cover the cost of grinding these unwanted plants. It's unrealistic to expect farmers to take a more expensive route to dispose of them, if they have a cheap alternative.

Highly recommend reading The Dreamt Land by Mark Arax if you'd like to learn more about this. The plants should never have been planted. Decades of unregulated groundwater pumping and effectively stolen federal water is feeding what used to be desert. There's no real plan for what happens when the water runs out (which is beginning to happen, evidently); just keep guzzling water while the going's still good.

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.

Likewise, the state should pay for my trash pickup, and if they don't, I'll just dump it on my neighbour's lawn. It's unrealistic to expect me to take the more expensive route to dispose of my rubbish.

I believe dumping your trash in your neighbor's lawn is illegal. Burning unwanted agricultural crops apparently isn't. You could make burning the crops illegal too, which would also solve the problem, but that would probably face legislative barriers. Paying the farmers to do the right thing might be the most straight forward solution.

For basic household rubbish? Yeah, state should definitely pay for that since it's in everyone's interest. I'm not sure you'll find much opposition here.

If they’re prohibited from burning, they'll consider that cost when they’re choosing the crop to plant?

The farmers could start a GoFundMe to cover the cost of grinding it up. I'm sure a lot of people in Silicon Valley would gladly pay to keep this smoke out of the air