Fodder I left is stored by wise man (6)
I believe the answer is:
silage
'fodder' is the definition.
(fodder used to feed animals)
'i left is stored by wise man' is the wordplay.
'left' becomes 'l' (common abbreviation).
'is stored by' means one lot of letters goes inside another.
'wise man' becomes 'sage' (sage is a kind of wise man).
'i'+'l'='il'
'il' going into 'sage' is 'SILAGE'.
(Other definitions for silage that I've seen before include "Fodder in store" , "Stored, dried animal fodder" , "Crop harvested for fodder" , "Preserved fodder for cattle" , "Form of fodder" .)