As a beanpole is set to absorb two fertiliser elements (5)
I believe the answer is:
lanky
'beanpole is set to absorb two fertiliser elements' is the definition.
I can't judge whether this defines the answer.
'as a' is the wordplay.
I cannot quite understand how this works, but
'a' could be 'an' and 'an' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for lanky that I've seen before include "Awkwardly tall" , "Tall and angular" , "Awkwardly long and thin" , "Far from podgy" , "Tall, thin and loose-jointed" .)