I've said this on other forums, and I'll say it here now:



Earth Pony Magic™ deals with the following:



Biomancy (plant magic, AJ has shown this a few times by having seedlings suddenly sprout when she is close)

Geomancy (earth/soil magic, earth ponies replenish the soil with nutrients, allowing crops to have several harvests per year, not to mention they can tunnel through without much effort, and they would also be good at mining)

Petromancy (rock magic, Maud's powers)

Myomancy (muscle magic, earth ponies are much stronger than unicorns or pegasi, note how Cheerilee was able to break out of Carousel Boutique and knock down a wall in the process), and

Capillomancy (hair magic, normal horses have tails which are 95% hair and the most they can do is swat flies out of the way, earth ponies use their manes and tails as extra appendages)