agronomy vs scientific agriculture

agronomy and scientific agriculture both are nouns.

Word	Noun	Adjective	Verb	Adverb
agronomy	Yes	No	No	No
scientific agriculture	Yes	No	No	No

As nouns, agronomy and scientific agriculture are synonyms defined as:

agronomy and scientific agriculture: the application of soil and plant sciences to land management and crop production

agronomy (noun)	scientific agriculture (noun)
the application of soil and plant sciences to land management and crop production	the application of soil and plant sciences to land management and crop production