Bring in a harvest (4)
I believe the answer is:
reap
'bring in a harvest' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for reap that I've seen before include "Derive as advantage" , "Save harvest, glean" , "Glean or cut as harvest" , "Gather 23dn" , "'As you sow, so shall you . . . .'" .)