The top left is Water, the top right is crystalline salt, the bottom is basin or field fenced up.
Ancient Chinese made salt by evaporating seawater (see the picture above), people still use the method to make salt nowadays.
The big seal script for Salt is
The small seal script for the character is
Similar to big seal script but more smooth and symmetrical.
The clerical script for the character is
The simplified song typeface is
The top is totally different, no any similarity to the old scripts.
The pinyin of 盐 is Yan2.