Some land where a salad plant is cropped (5)
I believe the answer is:
acres
This clue could be a double definition.
'some land' is the first definition.
(acres measure land)
'where a salad plant is cropped' is the second definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
(Other definitions for acres that I've seen before include "The Phoenix Park has 40 of them (5)" , "Land area measures" , "lots" , "Cares about these measurements?" , "large area of land" .)