" I always assumed that this term did not refer to moulding in the sense of forming a shaped ridge. Rather mould in the older English sense of earth. In which case Pádraig's "mowding" was my "earthing".
The bit that does (most) of the work by turning the soil over on a plough is called the mould/mold board. The stuff you pick up. .
. .Cheers, Tony.