Took farm away as a sign of man's presence (8)

I believe the answer is:

footmark

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'a sign of man's presence' is the definition.
I can't tell whether this definition defines the answer.

'took farm away' is the wordplay.
'away' is an anagram indicator (letters move away from their original places).
'took'+'farm'='tookfarm'
'tookfarm' anagrammed gives 'FOOTMARK'.

'as' is the link.

Can you help me to learn more?

I've seen this clue in The Daily Express.

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