desert soil vs dirt

desert soil and dirt both are nouns.

Word	Noun	Adjective	Verb	Adverb
desert soil	Yes	No	No	No
dirt	Yes	Yes	No	No

As nouns, dirt is a hypernym of desert soil; that is, dirt is a word with a broader meaning than desert soil:

desert soil: a type of soil that develops in arid climates
dirt: the part of the earth's surface consisting of humus and disintegrated rock

Other hypernyms of desert soil include soil.

desert soil (noun)	dirt (noun)
a type of soil that develops in arid climates	disgraceful gossip about the private lives of other people
	anything regarded as making something unclean
	the part of the earth's surface consisting of humus and disintegrated rock
	obscene terms for feces

desert soil (adjective)	dirt (adjective)
	(of roads) not leveled or drained; unsuitable for all year travel