(2 syl.) means hand-work (French, main-oeuvre), tillage by manual labour. It now means the dressing applied to lands. Milton uses it in its original sense in Paradise Lost, iv. 628:-
“Yon flowery arbours, ... with branches overgrown That mock our scant manuring.”
In book xi. 26 he says, the repentant tears of Adam brought forth better fruits than all the trees of Paradise that his hands manured in the days of innocence.