I'd say both mu2143 and Estepechito are partly right and partly wrong. Sea salt is a good source of micro-trace minerals, as the sea and ancient seabed salt deposits have had all of the minerals on Earth washed into them. The high sodium content can be harmful, but not on most non-coastal soils. 5-10 lbs per 1000 sqft (100 sqmts) is safe.
Fungi are very valuable for releasing minerals that are tied up in the native soil and rocks, but only if those minerals actually exist in that native soil. The Iodine found in sea salt is leached out of most soils, for instance.
www.soilminerals.com