I got a kick out of this one. tuber explains it above, which is how I parsed it during the play: “Land mass” is the definition; “like” synonym for AS; and Iowa is synonym for IA (the abbreviation for the state of Iowa).
Hello solvers, and thanks once again for taking a punt at one of my puzzles. Plenty more like this at https://crosshare.org/tuber so go ahead and check it out. If you enjoyed solving this one, go ahead and drop a like and/or a comment below - they always bring some cheer.
In the meantime, here's your wash-up:
ACROSS. 1A. "Spirit" = SOUL encloses "East" = E.7A. "Cry" = SHRIEK minus "I" given plain.8A. Homonym "pour in white wine" = ADD HOCK.
DOWN. 2D. Hidden in "malECHOir".3D. Reversal of "Marxist" = HARPO.4D. anag. KALE.5D. "Like" = AS + "Iowa" = IA.6D. Even letters in "aZtEcRoOt".