The high concentration of solutes in the soil, formed from the salt and melting snow, would result in

Actually since there are more solutes in the soil, then we could say therefore that there is a low water potential in the soil around that region. This creates a great problem for plants which are growing in that region, those plants would have a hard time absorbing water due to high concentration of solute in the soil.

a low water potential in the soil

sound moves fastest in solids because the molecules are tightly packed and it allows sound to vibrate