In an arable area, a little corn (3)
I believe the answer is:
ear
'corn' is the definition.
(an ear is a piece of corn)
'in an arable area a little' is the wordplay.
'in' indicates a hidden word.
'EAR' is hidden within 'arable area little'.
(Other definitions for ear that I've seen before include "'Give every man thine ..., but few thy voice' (Hamlet)" , "Speculator ignoring British" , "Go astray" , "Organ involved with balance" , "Organ of hearing" .)