Piece of countryside greenbelt comes with a qualification (6)
I believe the answer is:
degree
'a qualification' is the definition.
(I've seen this before)
'piece of countryside greenbelt comes' is the wordplay.
'piece of' indicates the answer is hidden within the clue.
'DEGREE' can be found hidden inside 'countryside greenbelt comes'.
'with' is the link.
(Other definitions for degree that I've seen before include "Position on a scale" , "Further education award - extent" , "Graduate's qualification" , "Award conferred on a 1 across" , "Measure for angle and temperature" .)