Fieldwork lasting into maturity (7)
I believe the answer is:
tillage
'fieldwork lasting' is the definition.
I can't judge whether this definition defines the answer.
'into maturity' is the wordplay.
'into' becomes 'till' (I can't justify this - if you can you should give a lot more credence to this answer).
'maturity' becomes 'age' (I've seen this before).
'till'+'age'='TILLAGE'
Can you help me to learn more?
(Other definitions for tillage that I've seen before include "Cultivation of the land" , "Cultivation of fields" , "Spadework" , "Preparation for growing" , "Cultivated land" .)