farmland vs ploughland

farmland and ploughland both are nouns.

Word	Noun	Adjective	Verb	Adverb
farmland	Yes	No	No	No
ploughland	Yes	No	No	No

As nouns, farmland and ploughland are synonyms defined as:

farmland and ploughland: arable land that is worked by plowing and sowing and raising crops

Other synonyms of farmland include cultivated land, plowland, tillage, tilled land, tilth.

farmland (noun)	ploughland (noun)
a rural area where farming is practiced	arable land that is worked by plowing and sowing and raising crops
arable land that is worked by plowing and sowing and raising crops