Question
I live in South Alabama, and have very small mounds of dirt coming up all over my yard.  I thought it might be grubs, but the grass doesn't come up easy as said.  I know without a pic it is hard to tell.  How can I determine what this is, and more important how do I treat this problem?

Answer
What do these little dirtpiles look like?

Small piles with little holes at the top can be a sign of invasion by ... drumroll please ... Earthworms.  Most feared: The Oriental Earthworm (appropriately named Perionyx excavatus by Botanists).  P. excavatus is a mini-backhoe with an evil reputation for piling up its castings and defacing innocent Lawns.  These shallow-burrowing Perionyx breed like rabbits.

Mounds built out of pellets of Soil a wee half inch wide, piled into mounds, can be a sign of Crawdads.  You need a body of water nearby to attract these or a drainage problem.  Got water?

Some species of Squirrels and other rodents will dig up Grass in search of food this time of year.  Around here, they're looking for Tulip and Hyacinth bulbs.

Moles build little hills as they work on their personal underground construction projects.  Different species can be a bigger pain in the neck than others.  When you walk on the Grass, your feet sink down, and the Lawn feels 'spongy'.

Gophers, especially Pocket Gophers, work on building hills out of Sand.

Fire ants usually erect their mounds in low-traffic places, but sometimes a Lawn will do.  Their hills smother Grass as they pile it on top, and they destroy root systems.  Other ants build hills here and there of varying size and shape.

Your Deep South location -- correct me if I'm wrong here -- narrows the list of potential suspects to all of the above.  A Grubs infestation, as you point out, comes with a lot of unhealthy (or no) roots, and your Lawn rolls right up with nothing to anchor it.  So I agree, this does not appear to be Grubs down there.  Can you describe these mounds further?  Any aforementioned clues resemble the 'mounds' you observe at when you survey the yard?  rsvp and thanks for your question!