Favouring healthy yield (6)
I believe the answer is:
profit
'yield' is the definition.
(I've seen this before)
'favouring healthy' is the wordplay.
'favouring' becomes 'pro' (I've seen this before).
'healthy' becomes 'fit' (associated in meaning).
'pro'+'fit'='PROFIT'
(Other definitions for profit that I've seen before include "Gain, return on investment" , "Clean up" , "Surplus earnings" , "returns" , "Use" .)