Hello txmoose and Welcome to the Forums!
That's a Seed that's fallen from one of your nearby Trees! But I don't think that's supposed to be a tillable/growable location hence the white ring of snow around it to let it blend into its normally snowy surroundings. You could try to dig it up with a tool like a Hoe or maybe a Pickaxe?
...ooooooor it's the functional end of a drainplug which is holding the pressures of many gigatons of water back because your Farm's existence is actually located on the underside of a giant ocean with that little stopper there holding back the furious pressures of water and angry deep sea sharks and ravenous gulper eels and sponges. I'm sure the sponges are peckish too. Totally haven't eaten in like days, very fearsome with grumbly tummies. They'll squeeze you to death. Ok maybe give you a nice loofah bath but their exfoliating is to be feared!
So maybe don't pickaxe it.