To work soil (4)
I believe the answer is:
till
This clue is a triple definition!
'to' is the first definition.
(I know that to can be written as till)
'work' is the second definition.
(to till is to work the land)
'soil' is the third definition.
(I know that till is a type of soil)
(Other definitions for till that I've seen before include "Plough" , "Cultivate - cash drawer" , "Money box" , "Work on farm" , "Cultivate - where the money goes" .)