Something soft on the ground (4)
I believe the answer is:
down
I believe this clue is a double definition.
'something soft' is the first definition.
(down can mean soft feathers)
'the ground' is the second definition.
(thesaurus)
'on' acts as a link.
(Other definitions for down that I've seen before include "Depressed - drink" , "Fluff - sorrowful" , "Depressed; swallow" , "Depressed - Irish county" , "Out of action; soft feathers" .)