Assessment of the Impact of No-Till and Conventional Tillage Technologies on the Microbiome of Southern Agrochernozems

Eurasian Soil Science - Quantitative characteristics of microbial communities in southern agrochernozems of the Stavropol region managed with the use of no-till technology and moldboard plowing...     

Microbial Communities of Interglacial and Interstadial Paleosols of the Late Pleistocene

Eurasian Soil Science - The taxonomic structure of microbial communities in the Late Pleistocene paleosols of different ages in the Central Russian Upland formed under contrasting climatic...     

Profile analysis of microbiomes in soils of solonetz complex in the Caspian Lowland

The taxonomic structure of the microbiota in two associated soils—solonetz on a microhigh and meadow-chestnut soil in a microlow—was studied in the semidesert of the Caspian Lowland. A highthroughput sequencing of the 16S rRNA gene was used for the soil samples from genetic horizons. A considerable reduction in the bacterial diversity was found in the lower horizons of the solonetz and compact solonetzic horizon with a high content of exchangeable sodium. In the meadow-chestnut soil, the microbial diversity little decreased with the depth. In both soils, a portion of archaea from the Thaumarchaeota group also decreased in the deeper horizons. In the soil horizons with the lower total bacterial diversity, a share of proteobacteria of the Enterobacteriaceae, Pseudomonadaceae, and Sphingomonadaceae families became higher. The difference between the structure of the microbial population in the solonetz and meadow- chestnut soil can be first explained by the different water regimes and soil consistence.     

Seasonal Dynamics of Microbial Biomass in Soddy-Podzolic Soil

Eurasian Soil Science - The seasonal dynamics of the structure of microbial biomass in a soddy-podzolic soil under fallow was assessed using luminescent microscopy. Samples from three soil horizons...     

Changes in the metagenome of the prokaryotic community of chernozems under the influence of mineral fertilizers

Molecular biology techniques provided the data on the composition of the metagenome of the prokaryotic community of chernozem soils with different anthropogenic loads by means of sequencing the 16S rRNA gene. The family markers that characterize the arable soil, fertilizers, and fallow soil were identified. The presence of a core (conservative) and accessory (labile and associated with soil processes or the conditions of the habitat of microorganisms) components of chernozem soils were detected.     

Microbiological parameters of aggregates in typical chernozems of long-term field experiments

The changes in microbiological parameters of aggregates (1–2 mm) in typical chernozems under different land uses as dependent on the intensity and character of anthropogenic loads were studied with the help of the real-time polymerase chain reaction (PCR). The samples from the following long-term field experiments were examined: permanent black fallow, continuous cultivation of potato, 17-year-old unmanaged fallow after permanent black fallow, and annually mown reserved steppe. The soil samples were treated in two ways. In the first case, the samples were air-dried, sieved through the screens to separate aggregate fraction of 1–2 mm, and microbiological parameters were determined in this fraction. In the second case, the samples were frozen immediately after the sampling, and the aggregates of 1–2 mm were manually separated from the samples before the PCR analysis. It was shown that air-dry aggregates of chernozems could be used for the quantitative analysis of DNA of microbial community in comparative studies. According to the quantitative estimate of the content of DNA fragments from different phylogenetic groups, the bacterial community was most sensitive to the type of the soil use, and its restoration after the removal of extreme anthropogenic loads proceeded faster than that of other microorganisms. The content of archaeal DNA in the chernozem under the 17-year-old unmanaged fallow did not differ significantly from its content in the annually plowed chernozems. The changes in the content of micromycetal DNA related to anthropogenic load decrease were intermediate between changes in the contents of archaeal and bacterial DNA.     

Microbiomes of the Soils of Solonetzic Complex with Contrasting Salinization on the Volga–Ural Interfluve

The analysis of ribosomal genes has been applied to study microbiomes of two soils of the solonetzic soil complex in the northern Caspian region. These soils—solonetz and quasigleyic chestnut soil—drastically differ in their salinity characteristics. The specificity of the vertical distribution of prokaryotes by the genetic soil horizons from the surface to the depth of 120 cm in these soils is discussed. The differences in the structure of microbiomes in the upper soil horizons can be related to the differences in the vegetation cover of the two soils, whereas the differentiation of microbiomes along the soil profiles is affected by the soil salinization. The solonetz is characterized by a much sharper decrease in the abundance and diversity of microorganisms down the soil profile in comparison with the leached quasigleyic chestnut soil. The total number of prokaryotes is mainly limited by the organic carbon content. In the upper soil horizons, Archaea from the phylum Thaumarchaeota are relatively abundant; their percentage decreases down the soil profiles. In the lower horizons of the solonetz, the genes of Marinobacter bacteria, which are considered marine inhabitants, have been found. It is probable that they persist in the soil since the previous transgression of the Caspian Sea.