interesting, so between desert and grass just cut it and one floating for the strip instead my example i made 2 floating. the part you said to cut and use world space is there examples or if you have time please show what you mean. and thanks for taking your time to answer it help me me a lot to learn.
One solution for this would be to make a custom shader that blends the two tiling worldspace textures, using vertex color, and it lays on top a separate fade/shadow texture tiled only horizontally to create the dark-edged transition. You would have to cut a strip where you want the transition to occur, and you'd have to…