Used to steer, this farmer (6)
I believe the answer is:
tiller
This clue is a double definition.
'used to steer' is the first definition.
(I've seen this before)
'this farmer' is the second definition.
(I've seen this in another clue)
(Other definitions for tiller that I've seen before include "It moves a rudder" , "one working on the land" , "used to steer" , "Boat steering gear" , "Bar to work rudder" .)