Fractional and group composition of humus podburs of South Yakutia

The goal of the study was to investigate the fraction-group composition of humus podburs in southern Yakutia in relation to bioclimatic peculiarities of humus formation in the region. The objects of the study were raw-humic and dry-peatypodburs widely represented in the southern part of the Aldan plateau in the basins of the Iengra and Timpton Rivers (56- 57° N, 124-126° E) with absolute altitudes of 600-900 m above sea level. Morphogenetic characteristics of soils were described according to the new classification system of Rus- sian soils. General physical and chemical properties and granulometric composition of soils were determined by stand- ard techniques in soil science. The content and composition of humus were analyzed by Tyrin’s method modified by Ponomareva-Plotnikova. Examined podburs were character- ized by short humus profile (