To some extent share a productive harvest (4)
I believe the answer is:
reap
'harvest' is the definition.
(I know that harvest can be written as reap)
'to some extent share a productive' is the wordplay.
'to some extent' says the answer is hidden in the clue (I've seen 'extent of' mean this (I've seen this in other clues)).
'REAP' is hidden within 'share a productive'.
(Other definitions for reap that I've seen before include "Glean or cut as harvest" , "'As you sow, so shall you . . . .'" , "Cut and gather (crop)" , "Harvest (a crop)" , "Save harvest, glean" .)