Soldier captures leaders of old brigade in desert (4)
I believe the answer is:
gobi
'desert' is the definition.
(Gobi is an example)
'soldier captures leaders of old brigade' is the wordplay.
'soldier' becomes 'gi' (government issue or general issue**).
'captures' means one lot of letters goes inside another.
'leaders of' indicates taking the first letters.
The first letters of 'old brigade' is 'ob'.
'gi' enclosing 'ob' is 'GOBI'.
'in' is the link.
(Other definitions for gobi that I've seen before include "Dry spot" , "Desert in China/Mongolia; cauliflower (Ind.)" , "Asiatic barren plateau which means 'stony desert'" , "Mongolian expanse" , "Desert, cauliflower in Indian cuisine" .)