Call on farm before group arrival (7)
I believe the answer is:
mooring
'arrival' is the definition.
(mooring is a kind of arrival)
'call on farm before group' is the wordplay.
'call on farm' becomes 'moo' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'before' means one lot of letters go next to another.
'group' becomes 'ring'.
'moo'+'ring'='MOORING'
Can you help me to learn more?
(Other definitions for mooring that I've seen before include "Permanent anchor" , "Making fast" , "securing vessel" , "Ship's berth" , "Place for anchoring or tying up" .)