There is this gap where the road mesh ends. The road is a seperate mesh because I am using adaptive subdivision and displacement modifiers, while the ground is a flat mesh. Also, the road is shrinkwrapped onto the ground.
I want to hide or smooth the gap, however cannot think of any ways to do it, other than adding extra grass.
Also, is there some way of blurring them together?
Maybe it would help to make the meshes intersect? As you say you shrinkwrapped them together, you likely would have to do that with another modifier, e.g. putting the nodes of the road along the edge into a vertex group and then use a displace modifier on the group to move them in z-direction. But it would only work nicely, if the amount of subdivision of the original mesh is fine enough to not pull half of the road below the ground that way.
To ‘blur’ you can mix your road material shader with a transparency shader. Depending on the size of the gap between road and ground, the sharpness and incident angle of the light and size of the blur region, you might get an undesired shadow, though.