Earth Protect is an Earth-type magic spell from Jade Cocoon 2. The spell reduces incoming damage from Skill attacks aimed at the user by 50%. Contrary to the description, the ability to return attacks against foes is nowhere to be seen, presumably dummied out. So, it is a worse version of the Defend command from Jade Cocoon 1... for 28 MP a turn.
Unless you wish to use the Resist Poison ability and not use the beast on Earth for one merging cycle, this move is of no real use. Use Libaridia or Protect instead.