Root vegetables, standard crops (8)
I believe the answer is:
parsnips
'root vegetables' is the definition.
(parsnip is a kind of root vegetable)
'standard crops' is the wordplay.
'standard' becomes 'par' (standard of play in golf).
'crops' becomes 'snips' ('snip' can be a synonym of 'crop').
'par'+'snips'='PARSNIPS'
(Other definitions for parsnips that I've seen before include "Veg" , "part of the traditional 27 [DINNER]" , "Spin spar around the vegetables" , "Snip spar with the vegetable" , "Fine words don't butter them" .)