Don't know if there is a simpler way of doing it, but you can select half of the land, set it to whatever, then do the same for the other side
sounds good ill try it ok it wasnt like i was looking for, but thanks EDIT by Moderator: merged posts, please use the edit button instead of double posting.
Well if you want a checkerboard. Just make a 2x2 area with the blocks, then use //stack till how big you want it to be