What is "lixivial salts"

Lixivial \Lix*iv"i*al\, a. [L. lixivius, fr. lix ashes, lye ashes, lye: cf. F. lixiviel.]

1. Impregnated with, or consisting of, alkaline salts extracted from wood ashes; impregnated with a salt or salts like a lixivium.
   --Boyle.

2. Of the color of lye; resembling lye.

3. Having the qualities of alkaline salts extracted from wood ashes.

   Lixivial salts (Old Chem.), salts which are obtained by passing water through ashes, or by pouring it on them.