Annotation of the results obtained in 2016
An approach for differentiation of soil erosion levels (acceptable, unacceptable and critical) was proposed and tested on typical and leached chernozems (Kursk region). This approach includes the estimation of humus content level, what is more reliable for the purpose of differentiation when compared to the conventional method from both experimental and theoretical aspects. This approach is based on the estimation of the minimal (Kershens, 1992) and critical humus content (Kiryushin, 1987). This gradation of soil erosion levels based on the estimation of humus content level is the foundation Kershens’ conception (1992) about the transformable and inert soil organic carbon. In our opinion, the degree of soil disruption by plowing is mainly associated with the loss of the transformable, easy-renewable organic matter, while erosion is associated with prevalent loss of inert humus (identified as minimal), which is formed in long-term period of fallow. Easy-renewable components of organic matter are being lost to the minimal values of humus content, while hard-renewable components are being lost below these values. When the humus content value is low enough to lead to the deterioration in physical soil properties, the level of erosion is considered as dangerous. The particular examples of the original approach usage for the typical and leached chernozems with varying degrees of erosion were shown. Based on the generalization of experiments for bio-physical-chemical diagnostics of the quality of soil organic matter in soil structural units the "Conceptual model of the soil aggregate structure response to organic matter transformation and humification" was proposed. The main statements are: 1. The main transformation of plant residues occurs in soil aggregates. 2. Transformation of plant residues results in the formation of aggregates. 3. Depending on the plant residues structure, on the first step of aggregation large aggregates (3-10 mm) or small ones (0.25-1 mm) are formed. After that in the process of organic residues transformation small aggregates become larger and large aggregates break up. 4. As a result, the middle-sized aggregate fraction (1-2 mm) accumulates in soil and contains the main carbon pool, where humic substances, most stable part of the soil organic matter, are accumulating and maturing. Plants produce and renew the soil organic matter, and soil organic matter itself contains the nutrients for plants. The higher isthe soil organic matter pool and ability of microorganisms to mineralize it, the greater is the availability of plant nutrients, the plant productivity and the amount of root exudates and plant debris in soil. Consequently, microbial biomass grows faster and the reproduction of soil organic matter is greater. In grain-tilled crop rotation on typical chernozem the yield increase of four crops in plots with organic and mineral fertilizers correlated with the content of mobile organic matter, extracted by solution of 0.1 N NaOH (r = 0.426, P <0.0001), but there were no correlations with total organic carbon and active organic matter. On the contrary, in the plots with only organic fertilization (manure, green manure, by-products) the yield increase was well predicted by total (r = 0.521, P = 0.002) and active (r = 0.638, P <0.0001) organic matter. Thus, in the agrocenoses the functional links between pools of soil organic matter and plant productivity are masked or mediated by decomposes and mineral fertilizers, so the quantitative correlation between the yield and the soil properties are usually stochastic and not always reproducible. The information about the structure and diversity of microbial communities in genetic horizons of soil in different bioclimatic zones and land-use systems was obtained with help of metagenomic analysis. We found out that the soil bacterial community, according to the metagenomic data, mainly contains nine phylum: Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Gemmatimonadetes, Planctomycetes, Proteobacteria and Verrucomicrobia. The dominant phylumes of bacteria in all studied soil microbiomes, regardless the horizon depth, were Proteobacteria and Actinobacteria. Phylum Actinobacteria, including many xerotolerant strains, represent the largest persentage of the soil microbiome in dry and warm climate (30-40%), and the lowest persentage in the soil microbiome in cool and wet climate, for example in podzolic soils (10-20%). There were scarcely studied strains of Archaea (phylogenetic group Thaumarchaeota) in most of microbiomes. These Archaea, which are widespread ammonium oxidizers, were related mainly to the topsoil, rich in organic matter. There was the greatest persentage of Thaumarchaeota in microbiome in the upper horizons of the steppe soils. It was shown that soils with more differentiated profiles also have contrasting composition and diversity of microbial communities. Soil horizons, which are sharply distinguished from adjacent horizons by number of physical and chemical properties (for example, eluvial horizons and plow-pan horizons of chernozems),also have significantly different biodiversity of the prokaryotic community. By methods of molecular biology we studied the aggregates extracted from the humus-accumulative horizon of chernozems and sod-podzolic soils; the agriculturally transformed soils were also included in the study(chernozems under"continuous potatoes" and "permanent fallow" from Kursk agro-industry Research Institute; podzolic soils under grain-tilled crop rotations from Moscow region from Central Experimental Station, Pryanishnikov Institute of Agrochemistry). Despite the general idea of the difference between inner and outer parts of aggregates, and, consequently, the difference in microbial communities, these microbial communities had common phylogenetic content. The difference in quantity was significant. According to the Real Time PCR analysis, the quantity of Bacteria and Archaeain creased in the inner parts of all aggregates in studied common and agriculturally transformed soils. The different data was obtained for fungal DNA; the highest amount of it was found inside the aggregate and smaller amount in the outer part of aggregate. That can be explained by the preference of anaerobic conditions for the development of this group of eukaryotes. There was a difference in the bacterial, archaeal and fungal DNA quantity in different types of soils. The maximum number of bacterial and archaeal 16s rRNAgenes was found in undisturbedchernozems, while the maximum number fungal 18s rRNA genes was found in agriculturally transformed podzolic soils. Thus, the ratio of quantity of bacterial, fungal and archaeal DNA can serve as an indicator of biogenic soil preservation under the agricultural use. Together with the Center of expertise and analysis of biogenic raw materials "Humus sapiens" we prepared the technical documents on certification of humic acids extracts for typical chernozem and podzolic soil in order to give them the status of standard state sample and transferred the samples to Rosstandart.

 

Publications

---

Annotation of the results obtained in 2014
There were provided a fundamental generalization of the theoretical and experimental works on the problem of the organic matter of arable soils and proposed theoretical development "Evolution of the dominant paradigm in the study of soil organic matter", they were approved at the 19th All-Russian School "Ecology and soil" (Pushchino) and 5 of the International Symposium "Bioinert interactions in natural and artificial systems "(St. Petersburg). There was presented historical and genetic paradigms in the study of soil organic matter (agronomy, soil-genetic, environmental, including the agro-environmental). In the framework of modern agro-ecological paradigm discussed soil-ecological functions of organic matter (biological, physical, chemical, and environmental). Set out the concept of composition, structure and nature of soil organic matter (chemical, biochemical and bio-physico-chemical, eco-bio-physical and chemical). There were comparisons of the values and functions of the conceptual pools of organic matter in arable soils with a plurality of fractions allocated analytically. There were provided a critical analysis of the definitions in the field of soil organic matter and proposed the original author's definition of humus and humification process. A system of integrated diagnostic quality of soil organic matter by the ratio of fractions isolated biological, physical and chemical methods. There were obtained the first data indicating a relationship between the quality of soil organic matter and structural organization of the soil aggregate. There was shown that water resistance of aggregates typical chernozems after removal of hard anthropogenic impact is restored quickly enough, and the process is much faster than the recovery of the total number of agronomic valuable aggregates. As a result of experimental studies agrogenic transformation of organic matter in these soils structural units following main conclusions: in the process of aggregate formation waterproof units formed first. This output is consistent with a dominant performance in the current literature on the leading role of fresh organic matter in the establishment of water resistance of soil structure. It was found that the biological indicators (the value of the active pool, the proportion of active organic matter in the bulk organic carbon (OC), the ratio of fractions differing in the rate constants of mineralization are indicate OC-mineralization activity and biological stability) is sufficiently sensitive display heterogeneity of organic matter contained in the structure-soil aggregate fractions and the influence of chemical and biological agents used in the optimization of fertility different origin and properties of sod-podzolic soils and typical Chernozems. Expe rimentally proved that in a number of structural and aggregate fractions of Sod-podzolic soil contained in the 1.1-1.8 times less active organic matter than in the whole sample of soil, and in some others - 1.1-1.4 times higher. High content of active organic matter characterized by the fraction <0.25, 2.1 and 3.2 mm. Multivariate analysis of variance evidence for the first time the contribution of the various elements of the variation in the Agri-active pool of organic matter in typical Chernozems soil, forming a descending series: manure (58% of the total effect) → green manure (15%) → by-products (12%) → mineral fertilizers (8%). Found an additive effect combination of manure, green manure and by-products, while the use of mineral fertilizers reduces the amount of active growth of the organic matter in the soil. It was found that the typical Chernozems soil microbiome is largely subject to seasonal fluctuations due to changes in dietary patterns, humidity and temperature. However, the presence of a significant ctast components determines the stability of the soil microbial community to the possible adverse effects of environmental factors. It is shown that the system of land tenure is a determining factor affecting the taxonomic composition and structure of microbial complex Chernozems soil, the size of the structural units in less impact on the spatial organization of prokaryotic complex of soil microorganisms. A number of components accessory prokaryotic microbial communities that can serve as indicators of soil processes occurring in the recovery of soil fertility. At the same time found such unique components of this community, which is accompanied by the degradation of agro-ecological condition of soils. It was developed a project of specifications for the development and certification of humic acids typical Chernozems and Sod-podzolic soil in accordance with the normative acts in Russia in order to give them the status of the state standard sample. Justified and documented procedures once the extraction and isolation of humic acid soils. Selected and prepared for extraction of humic substances typical chernozem soil mass.

 

Publications

---

Annotation of the results obtained in 2015
Created converged methodology, which is based on the fundamental conceptual and theoretical views on the composition, structure, properties and functions of soil organic matter, and system analysis (physical, chemical, biological) methods of study. In order to assess the impact of various agro-bio-technologes on the transformation of content, structure, properties and functions of soil organic matter, followed by the elaboration of regulatory measures to optimize food crops and sequestration of organic carbon studies suggested the following algorithm: 1. Determining quantitative levels of humus content of the soil of a particular area and ranging its to one of four classes of the humification: less than the minimum, low, midle and high. 2. Establishment of values of transformed, active, slow and passive pools of soil organic matter. 3. Determination of the content and composition of labile, mobile and mineralized organic and humic substances in the aggregates, grain size and density fractions of soil. 4. Obtaining quantitative indices reflecting the proportion of labile, mobile and mineralized fractions of blank organic matter soils. There were evaluated the effect of land use types and systems of fertilizers on the soil structure and aggregates composition of sod-podzolic sandy loam soil (Vladimir region) and qualitative characteristics of soil organic matter . Chemically labile and easy microbial biodegradation components of organic matter are sensitive display it with the transformation caused by tillage and other treatments influences. An original conceptual scheme of division of soil organic matter on the active, slow and passive pools was proposed. The humus horizon of sod-podzolic sandy loam soil contain: in the active field is 6-11% of balk C, slow - 34 – 65 %, and passive - 26-94 %. It proposes a molecular genetic approach to health and microbiological assessment of the resource potential of soils Russia. The authors of the proposes - project participants (Chernov TI, Ivanova EA, Semenov MV, Thakahova AK,) awarded the Government of the Russian Federation in 2015 in the field of Science and Technology for young scientists. A test system to conduct a comprehensive biomonitoring of soil, including soil sampling, transportation, storage, extraction of DNA, a system of long-term storage of DNA preparations, the preparation of libraries of 16S rRNA gene and their analysis using a new generation of sequencers were promotion. A study of seasonal variability (spring - summer - autumn) taxonomic structure of prokaryotic microbiome chernozem Stone Steppe (Voronezh region). Substantial differences in the structure of microbial community of arable soils regardless of the season, especially for members of the phylum Firmicutes, Gemmatiomonadetes and Verrucomicrobia. It is shown that long-term use of contrasting doses of fertilizer does not affect the structure and taxonomic diversity of prokaryotic communities of arable Cernozems. We studied taxonomic structure of microbial community units of aggregates of Chernozems under long contrasting options field experience (Kursk region) by sequencing the 16S rRNA gene. For analysis the aggregate size fraction <0.25, 2-5 and> 7 mm obtained by sieving of soil samples with natural humidity. The largest number of prokaryotic biomass (bacteria, archaea) recorded in fractions <0.25 mm, and aggregates of 2-5 mm; while the biomass of bacteria and archaea was decreased in the series: fallow> permanent fallow> undisputed winter wheat. The maximum number of fungi observed in the fraction <0.25 mm of permanent fallow in all studied variance of winter wheat. It is proved that the system of agricultural use has a significant impact on the structure of prokaryotic community of Chernozem in compare size of the aggregate fractions. The greatest biodiversity was in samples of variant "deposit", while statistically significant maximum of index Shannon and phylogenetic diversity (PD) recorded in fractions <0.25 mm and 2-5 mm in "deposit". In general, the fraction of small size (<0.25 mm) have greater diversity performance than the larger structural units.

 

Publications

---