In Siberia taiga zone in long seasonal frost conditions original taiga solodic long-seasonally frozen soils are formed. These are a complex natural formation which has in its profile both modern and relict signs. They develop on red-colour aeolation residue of which sodium cation is a constituent. The soils are distinguished by a sharp profile differentiation according to eluvium-illuvial type, weak acid reaction of the upper and alkaline reaction of the lower profile parts, sodium ion is periodically present in the absorbing complex; illuvial horizon is characterized by a prismatic structure, carbonates lie high (60-70 cm); there is a maximum accumulation of iron in the upper profile part; the second maximum of it is absent in the illuvial horizon. The listed signs and attributes point to the development of a large variety of soil processes in the past and present. Specific character of modern bioclimatic situation (little precipitation, predominance of evaporation in spring-summer time, deep freezing of soils and their late thawing) points to the fact that profile differentiation according to eluvium-illuvial type occurred in the former moister soil formation stages, possibly in the optimal stage of holocene. At present the soils are in a relative balance with the environment bioclimatic situation. Frost cracks filled with alien matter and rather high calcareousness of the lower profile part belong to the relict signs. Inconstancy of soils attributes is connected with a different degree of development in time of humus accumulation, alkaline hydrolysis, lessivage, gleyification and frost processes. The latter plays the leading part in soil formation. Deep freezing and late thawing results in the soils being in moist condition for a long time. In this case overfrost vadose is formed. The result of it is the development of eluvium-gley process. In dry periods of time periodically washing water regime goes over into exudate and as a result of it mineralized solutions going upwards occur. It leads to soil profile alkalinization. The fact that lessivage and gleyification development takes place at different times is connected with it.

Unfavourable temperature regime of soils limits the development of sporulating bacteria forms and actinomycets, and acid reaction of humus horizons and nutrition lack preclude the vital functions of nitrificating microorganisms. A very small proportion of fungi points to the weak development of eluvium process in the soils in modern conditions.

V. N. Gorbachev
P. O. Box 8750
Akademgorodok
Krasnoyarsk  660036
RUSSIA
Tel.: (3912) 494604