organic fertilizer vs organic fertiliser

organic fertilizer and organic fertiliser both are nouns.

Word	Noun	Adjective	Verb	Adverb
organic fertilizer	Yes	No	No	No
organic fertiliser	Yes	No	No	No

As nouns, organic fertilizer and organic fertiliser are synonyms defined as:

organic fertilizer and organic fertiliser: a fertilizer that is derived from animal or vegetable matter

Other synonyms of organic fertilizer include organic.

organic fertilizer (noun)	organic fertiliser (noun)
a fertilizer that is derived from animal or vegetable matter	a fertilizer that is derived from animal or vegetable matter