They make "plaster cutting blades'' for sawzalls just have to take it slow and easy. Acme or any of the big box stores have them. Made out of tempered steel so will handle the sand in the plaster.
Watched the renter seeding corn up by the farmsted. It don't take long with 24 row planter. Far cry from when my dad used a 2 row JD and checked the corn so you could cultivate both ways. How time flys.