Is it realistic to "salt the earth" in a kingdom/around a city?

I have a story in which a King, knowing his kingdom will fall, would like to have a scorched earth policy. The King would order all residents to begin salting the earth to ensure nothing there can grow. The city would have plenty of salt nearby as it is situated near a salt mine (I'm personally imagining Salzburg). There's some historic accounts of "salting" cities to starve people so it was thought about in the classical/medieval eras but all accounts seem to be very vague and improbable.

Let's say you were to salt a 5km radius from a city. That comes out to nearly 20,000 acres. And for a larger area, say 10km radius from a city that's an insane 77,000 acres to have to salt. And initially I wanted it a 20km radius which is 310,000 acres.

I'm not entirely sure there was enough salt throughout the entirety of pre-industrial earth to be able to salt anywhere near that much, even if only half was farmable land.

But the problem is any smaller and I can't see it being that large of an impact.

The question actually becomes three fold:

1. How much land realistically would need to be salted around a city to starve residents?

2. How much salt would this require?" 

3. Even with a literal salt mine would it be realistic for an average sized kingdom to already have/have to produce that much salt within a reasonable time frame (say in under 3 months before the invasion)?

" I know different soils and different plants react to salt differently, so for simplicity assume they only grew wheat (or any other grain) in whatever soil can support the grain.

posted over 6 years ago

Thatguypat‭

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