He special merits of Z.A. Waksman and I.V. Turin are marked in the development of soil humus and organic matter theory. Little-known pages ex vivo of these outstanding experimentalist scientists, founders of two schools and acknowledged leaders in the investigation of the soil organic matter, are presented in the article. A comparative analysis of theories by I.V. Turin and Z.A. Waksman on the origins, composition and properties of the soil organic matter is given. Actual conceptions, ways and methods of the organic matter fractioning are described in the work. The alternative points of view on the humine matters of soils by I. V. Turin and Z. A. Waksman are considered. A brief review on the heteropolymeric and supramolecular models of soil humic matter composition is presented.

Theories and points of view of soil science classics, such as V. V. Dokuchaev, I. V. Turin and M. M. Kononva on chernozem organic matter are reviewed in this work. The achievements of the leading researches of soil biology and biochemistry of Dokuchaev Soil Science Institute (D. V. Khan, M. Sh. Shaimuhammetov, N. A. Titova etc.) in the investigation of chemical and physical functioning of organic matter and the products of organo-mineral interaction of chernozemic soils. The author variant of level system for organic matter content in chernozem is presented in the work. The level system consists of minimal, median, maximal and critical levels. The convergent scheme of the investigation of the organo-mineral interactions of soils is presented. This scheme combines the Savvinov sieve method in modification of Khan and granulo-densimetric fractionation functioning by Shaimuhammetov-Travnikova, chemical and biokinetic fractionation. The particular examples of the application of this scheme on chernozems in conditions of long-term experiments is presented.

The consumption specters of organic matter fractions in ultraviolet and visible parts of specter (UV-visible specters) were investigated. The specters of soluted organic matter, as well as labile humic matters and humic matters itselves, which were extracted from small, medium and large aggregates from typical chernozems of long-term experiments were investigated. The samples of undisturbed chernozems, which are annually collected in the annually hayed steppe and from the chernozem with extreme organic matter degradation, were used (variant of long-termed experiment - irreplaceable black fallow since 1964). On the basis of specters obtained the parameters of optical indices SUVA254, E2/E3, E4/E6 were calculated. The highest differences between the aggregates were revealed in extracts of organic matter. The differences were lower for labile humic matters. There were no differences revealed for humic matters between the optical indices for different aggregates of one type of chernozems use. It is shown that all of the three parameters are not changed symbasically. Hence, all of the three parameters should be used for complete spectral characteristic.

The modified variant of granulo-densimetric fractionating method allows us to separate the functionally valuable compounds of the soil organic matter (OM) with different localization within the soil matrix. It gives us an opportunity to specify their role in the soil forming processes, and also the factors, which regulate their forming and changes under the impact of the external conditions. The free (non-aggregated) OM, which is localized in space between aggregates, and stabilized OM in the composition of microaggregates. Such an approach allows us to assess the soil microstructure more validly. The two groups of microaggregates are separated in the soil. They are differed in the degree of sustainability to dispergating impact of ultrasound. There are also differences in the form, structure, composition and properties of organic and organo clayey compounds, and the type of stabilizing agents. The correlation between the microstructural organization and OM sustainability was set for the zonal range of basic soil types of Central Russia. It is revealed that the micro-agregation degree in the soil of the zonal range is increased due to the heaving of the soil texture, which reflects the dominating role of the organo-clayey particles in their forming. The difference between the sustainable and unsustainable microagregates is in the amount of these particles and in character of the organic compounds.

The structure and agrogenic transformation of organic substance in chernozems of Middle Siberia are considered (within Krasnoyarsk Krai, Khakassia and Tuva). The comparative-geographic, comparative-analytical and stationary observation methods are used in this work. These investigations are based on ideas of academician I.V. Tyurin, who had a Krasnoyarsk period in his creative work. All of the forms of humic compounds of chernozem type are presented in the studied soils. The mineralized (transformed) pool of organic matter in chernozems (19-28 t C/ha) is characterized by set of the plant residues, microbial biomass and a mobile humus. The entrance of plant residues into the soil of a graminae-fallow-hoed crop rotation makes 3.32 t C/ha per year, graminae-grass - 3.89 C/ha per year. The contribution of living roots reaches 40-70% of year stocks of the plant residues. The entrance of additional portions of "fresh" plant material with straw and green manure increases the mineralized pool of the organic matter and its decomposition intensity. The amount of microbial biomass in an arable layer of chernozems fluctuates from 1.5 to 3.0 t C/ha. The decomposition of plant residues occurs at k = 0.37-0.44. The share of a mobile humus (water- and alkaline-soluble compounds) as a part of the mineralized chernozems OM reaches 69-77%. The seasonal variability of mobile humus concentration is determined by the unequal rate of plants death, the entrance into the soil and decomposition of plant residues, different intensity of their transformation in neoformed humic substances. Losses of humus mobile compounds in soils of Krasnoyarsk Krai (0.23 t C/ha per year) contain about 7% of his expenses on the forming of net primary production and are compensated here by a neoformed humus at 91%, in soils of Khakassia - at 34%, Tuva - only at 16%.