Cares about some land (5)
I believe the answer is:
acres
'some land' is the definition.
(acres measure land)
'cares about' is the wordplay.
'about' is an anagram indicator.
'cares' is an anagram of 'ACRES'.
(Other definitions for acres that I've seen before include "Land area measures" , "Cares about the land measures" , "Cares about these measurements?" , "Units of land measurement" , "Cares about the tracts of land" .)