Deuteronomy 29:23

Of salt. This salt was of a bituminous or sulphureous nature, which would burn like oil, and was sometimes used in lamps. (Herodotus, ii. 62; Pliny, [Natural History?] ii. 104.) It dried up the moisture of the earth, and rendered it barren. For which reason, it was scattered upon such places as were no longer to be cultivated, or inhabited. Abimelech sowed some on the ruins of Sichem, Judges ix. 45. It seems that Palestine now feels the effects of this curse; as, for the most part, it is uncultivated, and a desert, though once so flourishing. (Calmet)