Roll of turf (3)
I believe the answer is:
sod
'roll of turf' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for sod that I've seen before include "A piece of sward." , "A lulmp of turf" , "Piece of turf; a Law named for him" , "A lump of turf (3)" , "'Sward, turf (3)'" .)