I agree with you. I’m interested in this idea — from Carthage forward. I’ve never seen any documentation of it actually being done except symbolically. You’re right that you would need vast quantities and I’d imagine it would be leached out of the soil by rainfall in a relatively short period of time. Look at Carthage: After the Romans conquered it, it became a major grain growing center. It takes a lot to keep the corn dole going, you know!
Thanks - I’m not aware of any instance where this had actually happened. I suppose flooding areas with sea water might come close, but the technology to do that to areas above sea level was not available back then, either. (OK, lots and lots of slaves carrying buckets of sea water inland...LOL.)