Humus of soils of the Altai Mountains

Abstract

Data on the humus composition and specific features of soils in the Altai Mountains obtained in the long-term studies initiated by R.V. Kovalev are discussed. The average statistical values for the content of the main humus components and their ratios in different soil types were obtained by processing the data on 307 soil pits. The comparison of the soils belonging to the same type and occurring in the northwestern, central, and southeastern regions of the Altai Mountains in terms of the C ha/C fa ratio (one of the integral indices of the humus composition) showed that there were no significant differences between them. The overlapping intervals of the average values of this ratio testified to this fact. For instance, the average C ha/C fa ratios in the mountain tundra soils of the regions mentioned amounted to 0.70 ± 0.03; 0.72 ± 0.02; and 0.69 ± 0.03, respectively, and, in the mountain meadow soils, they amounted to 0.67 ± 0.03; 0.69 ± 0.04; and 0.67 ± 0.03, respectively. The mountain brown forest soils that are components of the soil cover only in the northwestern and central regions also differ insignificantly by this parameter (0.88 ± 0.05 and 0.89 ± 0.03, respectively). In the soils of the Altai Mountains, the dependence between the portion of humic acids and the mean annual air temperature (HA (%) = 29.54 + 1.06T(°C), r = 0.71) and the ratio of the portion of fulvic acids to the mean annual precipitation (FA (%) = 9.70 + 0.029W, r = 0.74) was shown to be similar to those in all the soils of mountainous southern Siberia. These facts enabled us to apply regression equations for a quantitative reconstruction of the paleoclimate components according to the humus composition.