Vallejo Dark Earth is a nifty paste for jazzing up your bases or dioramas. It says it is a "gritty paste og acrylic resin, pigment and micro particles", and I can only assume that last bit to be the ground bones of enemies. It is what it says it is.
I painted my bases brown first, but you can probably skip this stage if you prime black, brown or grey. These were white though, so I played it safe.
The paste is easily applied without being too messy. I am using an old cheapo crafts brush which usually sees use when I apply liberal amounts of cheapo craft paint to bases. Using a nice brush would be plain stupid, but a knife or spatula, clay shaper or whatnot might also be fine. The texture is like sandy plastic putty, and it can easily be used to hide the slot in the base or weird gaps between feet and base.
One can supposedly make track marks or other cool effects, but I have yet to try that. Letting it dry and building it up or anything like that seems very easy though. Planting grass tufts in it would also be easy, and likewise with battlefield debris etc.
It looks like dirt! It dries in about 45 min at room temperature and looks pretty much the way it looks going on. Basically the next step is to just dab on some spots of glue, flock/grass/tuft and then call it a day, but I suppose one can drybrush it to lighten highpoints, but I did not feel the need or urge.