Bazhina N.L., Ochur K.O., Ondar E.E., Zakharova E.G., Ryabova N.N.
HUMUS OF MOUNTAIN MEADOW SOILS OF WEST TUVA ^{[№ 12 ' 2017]}
Data on the humus composition of mountain meadow soils in the western part of Tuva, occupying the lower boundaries of the highland region of the Alashsky upland of the Western Sayan, the Shapshalsky ridge of the Western Sayan and the ridge of the Western Tannu-Ola, are summarized. Methodological features of the work consisted in the selection of soil samples, which was carried out in detail by a continuous column every 5–10 cm and(or) less within the visible boundaries of the horizons, as well as in the use of the microclimatic data: average annual air temperature, average annual precipitation and the sum of temperatures above +10 °C, calculated for each individual section, according to the regression equations derived for Tuva territory that include interrelationship of climatic characteristics with altitude above sea level, and taking into account the influence of the exposure of the slope and the wind rose. As a result of the analysis of generalized materials, the specific features of the humus composition of mountain meadow soils are revealed, depending on the ecological conditions of their formation. They consist of different contents of total organic carbon, the amount of humic acids associated with calcium, and the proportion of mobile fulvic acids in the composition of this component. At the same time, mountain meadow soils, irrespective of local conditions of functioning, within the uniform bioclimatic boundaries, have a humus-fulvate composition of humus with very close values of the ratio Cha:Cfa, which lie in the range of 0.77–0.99, but more than 50 % exceed the value of 0.9, and also a relatively high proportion of humic acids, bound clay minerals of soils (fr. HAIII), which is typical for soils that are affected by the processes of freezing. This does not contradict the generally accepted understanding of the humus composition of mountain meadow soils of other regions of Russia.

Bazhina N., Ondar E., Ochur K., Dergacheva M.
HUMUS OF MOUNTAIN TUNDRA SOILS OF WESTREN PART TUVA ^{[№ 10 ' 2015]}
The features of the composition of humus mountain tundra soils depending on the position in relation to the glacier formed under different environmental conditions the western Tuva.

Dergacheva M.I., Bazhina N.L., Ondar E.E., Ochur K.O., Ryabova N.N.
ENVIRONMENTALLY INDUCED COMPOSITION AND PROPERTIES OF HUMIC ACIDS IN SOILS OF WESTERN TUVA ^{[№ 10 ' 2015]}
The correlation between the composition and properties of humic acids in western part of Tuva climatic parameters calculated for each individual object. It is shown that humic acids having a certain value of the ratio of H:C match as certain values of temperature and humidity (rain) at which the humic acids formed in such ratio of these forming elements.

Ondar E.E., Dergacheva M.I., Bazhina N.L., Ochur K.O.
HUMUS OF MOUNTAIN TAIGA SOD SOILS OF TODZHA BASIN (NORTH-EASTERN PART OF TUVA) ^{[№ 6 ' 2015]}
The composition of humus, structural features of humus profiles and specific elemental composition of humic acids of mountain taiga sod soils key area "Azas" (north-eastern part of Tuva) are discussed. According to the classification in 2014 WRB, these soils are Umbric Gleysols Dyst Soil sections are located on different positions of complex Catena that differ by relative height, expositions and a steepness of slopes. The vegetation cover is represented by light-forest of subtaiga nature-with rich grassland. The lower horizons of soil profiles are characterized by low temperatures. Analysis of materials of humus soil study showed that the features of its composition are higher value of Cha: Cfa and higher solubility (hydrolyzability) of humic substances and calcium humates share in them as well. This distinguishes these soils from analogues located in the European part of Russia. Characteristics of humus profiles depend on the exposure of slope on which the soil is formed and the soil position in the Catena, but in general the type of humus profile is characteristic as a forest soils. Specifics of of composition and ratio of elements in humic acids of the mountain taiga sod soils under study of the key area has been the lack saturation of of humic acid with nitrogen, a high proportion of carbon and relatively low values of H / C. Position in the relief has little effect on the elemental composition of soil humic acids under studied: the ratio of elements is changing the slope just as a trend. But the effect on the elemental composition of humic acid has a history of their formation which included the stage of development of steppe soils. Until now, in areas close to key sites "Azas" locally common steppe.

Bazhina N.L., Ondar E.E., Ochur K.O., Dergacheva M.I.
SOIL HUMIC ACID ELEMENTAL COMPOSITION OF WESTERN PART OF THE TERRITORY TUVA ^{[№ 10 ' 2013]}
Specificity of humic acid element composition of soils of some key sites of the western part of Tuva territory located in different landscape conditions is shown. Materials and the revealed laws are of interest as a part of data bank using for paleoenvironment reconstruction based on humic acid element composition.