The soil samples were taken from the following 5 different variants of over 30-
year-long reclamation: black fallow (BF), monoculture of winter wheat (WW), monoculture of winter
wheat with a single application in 1992 of lignite dust (WW + L), monoculture of alfalfa with orchard grass
in the proportion of 90/10% (A + G), and spontaneous succession (SS).