One has schemes about lowlands (6)
I believe the answer is:
plains
'lowlands' is the definition.
(thesaurus)
'one has schemes' is the wordplay.
I cannot really understand how this works, but
'one' could be 'i' (Roman numeral) and 'i' is found in the answer.
'schemes' could be 'plans' (I've seen this in another clue) and 'plans' is located in the remaining letters.
This accounts for all the letters.
This explanation may well be incorrect...
'about' is the link.
Can you help me to learn more?
(Other definitions for plains that I've seen before include "Large areas of level country" , "Flats" , "Grasslands" , "Flat tracts of land" , "Prairies" .)