An easy recipe for cracked earth bases, using PVA, GW Agrellan Earth, Army Painter Deadland tufts and three brown tones.
This recipe uses Agrellan Earth from Games Workshop. This is a technical paint with a crackle texture. I apply a layer of PVA glue to the base (and allow it to dry) before applying the paint. This seems to anchor it. Otherwise it has a tendency to flake off. The paints are just suggestions. Any dark, mid and light brown tones will do. Same with my choice of tufts. I picked Deadland tufts from Army Painter because I wanted a drab appearance, but there are lots of alternatives you could use here.