It’s important to match a particular scent, be it an attractant or cover, to the area. In the Midwest and New England states, apple-scented lures may work well, but not so much in the marsh and woods of Louisiana.
A persimmon lure might serve hunters better in the South.
Most earth scents smell like fresh-plowed farm fields. I went through a period during my early years experimenting with cover scents, where the earth cover scent busted deer on more than one occasion. I soon realized there were no freshly plowed fields in the marsh.
Unfortunately marsh-mud cover scent isn’t offered or found on the shelves of our local sporting goods stores — unlike earth scented wafer-like cover scents.