Book arable land for discharge of firearms (6)
I believe the answer is:
volley
'discharge of firearms' is the definition.
(as in a volley of gunfire)
'book arable land' is the wordplay.
'book' becomes 'vol' (short for volume).
'arable land' becomes 'ley' (ley can mean a piece of land for farming).
'vol'+'ley'='VOLLEY'
'for' acts as a link.
(Other definitions for volley that I've seen before include "A flight of missiles" , "Shot played before the ball bounces" , "Simultaneous discharge of a number of firearms" , "Salvo (of bullets)" , "Tennis, football, shot" .)