Hey. I am taking a wild swing here but this was voxel sniped was it not? If so you need to bring back the depth on your overlay brush back to 2 from 3 for your dirt. And you need to get some blend ball action going on on it. It will make it a heap smoother. Command is /b bb
For depth of 2 it is /b over d2

This is a good first terraform though. Well done.