A bit of arable area? (3)
I believe the answer is:
lea
'a bit' is the definition.
The definition and answer can be both quantities as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'of arable area?' is the wordplay.
'of' says the answer is hidden in the clue.
'LEA' is hidden in the letters of 'arable area'.
(Other definitions for lea that I've seen before include "Open country" , "Poetically, a piece of meadow or pasture" , "grazing area" , "Tract of pastureland" , "'The lowing herd wind slowly o'er the . . .'" .)