What’s needed for walking dog in meadow: quiet (5)
I believe the answer is:
leash
'what's needed for walking dog' is the definition.
(a dog is kept on a leash)
'meadow quiet' is the wordplay.
'meadow' becomes 'lea' (a lea is a grassy area).
'quiet' becomes 'sh' (both can be said to tell someone to be quiet).
'lea'+'sh'='LEASH'
'in' acts as a link.
(Other definitions for leash that I've seen before include "Restraint for a dog" , "Bind" , "Rope used to restrain an animal" , "Dog lead" , "Rope to control dog" .)