"Here lies our drywall, it covered the walls well...RIP"
drywall is Gypsum and paper. Pretty much boring stuff. Probably not going to do much to your soil. You don't really say where you plan to bury it, but I can say there is nothing I hate worse as a gardener than to come across a bunch of construction debris planted in the middle of my yard.
If you do insist on burying it, then BURY it. don't just leave it a couple of inches below the surface.
For all the effort of digging the hole, I'd take it to the dump.
On the other hand, if you have a backhoe and the hole is already there, maybe.