Manure (4)
I believe the answer is:
dung
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">manure</span>' is the definition.<br/ ><span class="explanation-format__explanation">(manure is dung used as fertiliser)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for dung that I've seen before include "Animal manure" , "Animal excrement" .)