Under the various forms of periodic cryogenesis (daily, annual, long-term, centenary and others) in the surface layers of lithosphere two cases are playing a significant role in continuity of biological factor of soil formation: 1) the mechanism of renewal of biotic life-activity, when the period of negative temperature influence is ended, 2) cycles of environmental conditions for biotic live-activity. The first (above-mentioned) case is characterized by such adaptations of living organisms as winter rest and anabiosis, as well as their ability to reproduction and settling. The second case is characterized with the presence of daily, annual, long-term, centenary and other recurrences of biotic live-activity that are connected with climatic and cryogenesis cycles.

According to these cases, the biological factor of soil formation is to be determined by continuity within the following specific forms: 1) "within daily" - when the temperature corresponds to living-organisms survival; 2) "within annual" - beginning from the time when the organisms are going out of the state of winter rest or anabiosis and up to the moment of their going into that state; 3) "within long-term" (and others) - beginning from the time of biotic settling until the time when living organisms pass into the state of rest and distruction.

Assuming continuity of biological factor as an obligatory reason for evolution of concrete soil and taking into account the above-mentioned varieties of continuity, one can state that corresponding kinds of soil evolution occur in reality, namely: "within daily", "within annual", "within long-term" and others.

 
Ivan V. Slesarev
Institute for Soil Sciences and Agrochemistry
SO RAN, Sovetskaya str., 18,
Novosibirsk-99, 630099, RUSSIA
Telephone: (3832) 225 088
Fax: (3832) 225 665
E-mail: soil@issa.nsk.su