(1):

(v. t.) To apply manure to; to enrich, as land, by the application of a fertilizing substance.

(2):

(n.) Any matter which makes land productive; a fertilizing substance, as the contents of stables and barnyards, dung, decaying animal or vegetable substances, etc.

(3):

(v. t.) To cultivate by manual labor; to till; hence, to develop by culture.