3D Models World posts a look at creating realistic terrain and shaders using Maya.
3D Models World has a look at how to quickly create a terrain along with realistic shaders in Autodesk Maya using Arnold. The tutorial covers a quick method for producing the ground involve using Google Earth and Sketchup. The second tutorial looks into creating the shading network for the ground textures.
The shader relies on using a combination of different textures by mixing them and blending them using Maya Hypershade. The tutorial is a free excerpt drawn from the Cinematic Forest Environments in Maya and Arnold Course. The course shows how you can create natural forest environments in Maya and Arnold without relying on any 3rd party plugins.