Combining two IMAGES so they fade into one another in a gradient or transition I've checked all the other threads on this question and there are ones similar but not quite explaining the effect I'm looking for.

Essentially in cycles, I want to fade a sand unit into a clay unit gradually transitioning from one to the other. The image shown has a harsh, unrealistic change that makes my already amateur equipment look appalling!!

 

I've set it up with two planes (1 Sand (below) and a similar Clay 1. Intuition says I should probably be using only one plane to get the gradient I want but this is what I have so far..



Thanks for any help
I'd say your intuition is correct, you don't even need to remake your materials.
Just use a single plane, and use a gradient texture as a mix value in the Factor socket of a Mix Shader node to fade between the two.

Then copy paste your two materials into the same shader tree and mix them together.

You may use a color ramp node to control the transition.