farming with desal water is insane. even with abundant power.

Leaving otherwise fertile farmland empty to use the lands allocated water on another field is insane, insane problems call for insane solutions

why ? at scale desal water via solar looks to be very reasonable thing ?

Current legal setups generally actively encourage people to waste water that they have property rights to. It would be infinitely better return on investment to reform that and put proper incentives in place, rather than work around it with technology.

farming requires a _lot_ of water.