Material sampler for the P11 construct has some ground textures (and a "haze ring" prop to conceal the hard UV seam between ground and sky).

Some of my ground materials employ a user-drawn map to control material effects; here such a map controls where lava flows:

I use Genetica 4.0 Studio to make asymmetrical seamless tiles from photos I take of my yard, the river bottoms, etc. seach checks runtime//textures//seachnasaigh//Genetica tiles : 886 tiles.

I often use a "scramble" mixture of two similar -but distinct- tiles to cover a large area so as to avoid an obvious repetition pattern.

Poser 12, in feet.  

OSes:  Win7Prox64, Win7Ultx64

Silo Pro 2.5.6 64bit, Vue Infinite 2014.7, Genetica 4.0 Studio, UV Mapper Pro, UV Layout Pro, PhotoImpact X3, GIF Animator 5