What is the origin of chernozem?

Chernozem “a soil common in cool or temperate semiarid climates, very black and rich in humus” is a borrowing from Russian chernozëm, a compound of chërnyĭ “black” and zemlyá “earth.” The first element derives from a root also found in the Slavic names Chernobog “black god” (also spelled Chernabog and Czernobog), one of two gods of fate in Slavic mythology, and Chernobyl, the site of a nuclear disaster in Ukraine, whose name derives from Russian chernobyl “wormwood” or, literally, “black herb.” This same root also appears in Sanskrit as the Hindu god Krishna, whose name means “black.” The latter part of chernozem derives from the Proto-Indo-European root dhghem- “earth,” which is the source of several land-related words, such as chthonic (from Ancient Greek khthōn “earth”), exhume and humble (from Latin humus “earth”), and chameleon and chamomile (from Ancient Greek chamaí “on the ground”). Further derivatives of this root include person-related terms such as bridegroom (from Old English guma “man”), hominid (from Latin homō “man”), and human (from Latin hūmānus, of the same meaning). Chernozem was first recorded in English in the mid-1800s.