Abstract:

Based on several ordinary investigations (including west slope, east slope and north slope) and long-term fix-position research of cryo-brown soil under the forests of the north area of Daxing'anling mountain, according to keys to taxonomic classification index of cryo-brown soil, Caocha natural reserve with wide representative characteristic which is in the west slope of the north area of Daxing'anling mountain is selected as the collecting site of cryo-brown soil standard profiles. According to describing standard of the soil profiles, and the soil analysis program and method in laboratory established by "The Research Program of the Chinese Soil Taxonomic Classification", the field collecting soil sample and analyzing soil in laboratory were carried out. The research result discussed about the condition of soil-forming in cryo-brown soil profiles and its basic characteristic, and based on the diagnostic horizon and diagnostic characteristic, studied the problems of the taxonomic classification of cryo-brown soil, and also studied and discussed the diagnostic surface horizon (humus surface horizon and gley surface horizon), diagnostic subsurface horizon (weathering B horizon, argillic horizon, spodic horizon and spodic characteristics) in the diagnostic horizons and the diagnostic characteristics including the freezethaw characteristic, soil moisture regime, soil temperature regime, the content of gravel on the surface to 50 cm soil layer.

Key words: Cryo-brown soil, Taxonomic classification, Diagnostic horizon, Diagnostic characteristics