Structural organization and matter differentiation of bolshezemelskaya tundra south-east automorphic soils
The detailed studies on automorphic loamy soils of the European North-East of Russia using up-to-date methods and approaches allowed tracing interdependence between soil structure components and between characters and sequence of their changes in time as well as differentiating between recent and inherited features and transforming them during cryopedogenesis. The soils were identified for two stages of pedogenesis. The stages were isolated on the basis of morphologic features (structural organization and differentiation of cutan complex), humus pedorelics, recent and inherited pedogenesis and cryogenesis processes and the intensity of lithomatrix transformation. Top soil has signs of recent cryogenic evolution phase. Middle and low soil went through the taiga soil formation stage diagnosable by fragments of clay cutans and buried humus horizon, high intensity of lithomatrix transformation. Cryogenic structural metamorphism of middle and low soil and deformation of cutan complex are aftereffects of a sudden temperature drop in the subboreal period of Holocene that caused a burial of middle-Holocene texturally-differentiated soil. The analysis of sand-silty cutans on recent migration ways of solutions diagnoses Al-Fe-humus illuviation process and conserving properties matter within aggregate reflect an eluvial-illuvial differentiation which is inherited from the taiga soil formation stage. Study of evolution, genesis, structural organization, differentiation of functioning products, high intensity of lithomatrix transformation and humus pedorelicts occurring in the south tundra subzone allowed to identify a combination of recent and inherited features connected with changes in bioclimatic factors in Holocene and human-induced impact. Diagnostic criteria of polygenetic soil genesis are offered.