Microbial Biomass,Carbon Stocks,and CO2 Emission in Soils of Franz Josef Land: High-Arctic Tundra or Polar Deserts?

Eurasian Soil Science - The biomass of prokaryotes and fungi, organic carbon stocks, and CO2 emission were studied in the Cryosols and Leptosols of Franz Josef Land. The highest carbon stocks were...     

Soils and cultural layers in Velikii Novgorod

Urban pedosediments (cultural layers) dating back to the 10th–11th centuries AD and soddypodzolic soils buried under them were studied in two archaeological excavations in Velikii Novgorod. Stages of their development were described. It was found that the buried soddy-podzolic soils at the latest stages of their development were cultivated or were formed under meadow vegetation. Weakly developed garden soils were described in the thickness of urban pedosediments. The lowermost organic cultural layers in Velikii Novgorod were waterlogged and represented peatlike mass with well-preserved wood remains. The oxidation of organic matter, gleyzation, and vivianite formation were described in them. The upper mineral layers were enriched in brick debris and building lime. The processes of organic matter mineralization, alkalization, calcification, zoogenic turbation, and biogenic structuring were clearly manifested in this part. Soil solutions infiltrated from the cultural layers caused some alkalization of the buried soddy-podzolic soil. Diagenetic carbonates and vivianite appeared in some loci within the eluvial and the upper part of the illuvial horizon of this soil. The entire cultural layer was subjected to contamination with heavy metals.     

Agrobacterial transformation in rape by the use of technology without the phase of regenerating plants from callus

Proposed changes in technology of performing the transformation in dicotyledonous plants were aimed to exclude the phase of regeneration. The seeds of transformed plants were used as recipients, while the appearance of transgenic variants occurs simultaneously with the formation of the first seed progeny T₁. The proposed technology completely lacks any phases connected with the necessity of cultivating some tissues in vitro, which permits one to avoid somaclonal variance with uncontrolled deviations from the initial genotype.     

Cryoconites as Factors of Soil Development in Conditions of Rapid Retreat of the Aldegonda Glacier,Western Svalbard

Eurasian Soil Science - Cryoconite is an organomineral sediment on the surface of glaciers. It has predominantly an eolian origin, demonstrates high microbial activity, and contains a relatively...     

Changes in carbon pool and CO<Subscript>2</Subscript> emission in the course of postagrogenic succession on gray soils (Luvic Phaeozems) in European Russia

An analogous time series of fallow ecosystems (gray soils (Luvic Phaeozems) plowed and fallowed for 2, 7, 20, 60, and more than 120 years) in the broad-leaved forest zone of Orel oblast has been analyzed. Changes in carbon pool and CO2 emission in the course of postagrogenic succession during the vegetation and winter seasons have been estimated. The restoration of ecosystems on Luvic Phaeozems follows regularities revealed in analogous studies of southern taiga Podzols and forest-steppe Chernozems. Analogously to the other studied zonal chronosequences, total annual soil respiration on Luvic Phaeozems reaches the initial level of undisturbed ecosystems simultaneously with the restoration of phytomass reserve, although significantly earlier than the organic carbon reserve in soils is restored. According to regression models, among the zonal fallows in European Russia, including the southern taiga (Podzols), mixed forests (Luvisols), broadleaved forests (Luvic Phaeozems ), forest-steppe (Chernozems) and dry steppe (Calcisol–Solonetz soil complexes), the mean annual soil respiration is maximum in the zone of gray soils and Chernozems. The increase in soil respiration under artificial wetting (Birch effect) on fallows in the broad-leaved forest zone is minimum among the studied zonal chronosequences: 1.1 ± 0.6 (no effect), which corresponds to the optimal hydrothermal conditions in this zone.     

Experimental studies and physically substantiated model of carbon dioxide emission from the exposed cultural layer of Velikii Novgorod

The results of quantitative assessment and modeling of carbon dioxide emission from urban pedolithosediments (cultural layer) in the central part of Velikii Novgorod are discussed. At the first stages after the exposure of the cultural layer to the surface in archaeological excavations, very high CO₂ emission values reaching 10–15 g C/(m² h) have been determined. These values exceed the normal equilibrium emission from the soil surface by two orders of magnitude. However, they should not be interpreted as indications of the high biological activity of the buried urban sediments. A model based on physical processes shows that the measured emission values can be reliably explained by degassing of the soil water and desorption of gases from the urban sediments. This model suggests the diffusion mechanism of the transfer of carbon dioxide from the cultural layer into the atmosphere; in addition, it includes the equations to describe nonequilibrium interphase interactions (sorption–desorption and dissolution–degassing of CO₂) with the first-order kinetics. With the use of statistically reliable data on physical parameters—the effective diffusion coefficient as dependent on the aeration porosity, the effective solubility, the Henry constant for the CO₂ sorption, and the kinetic constants of the CO₂ desorption and degassing of the soil solution—this model reproduces the experimental data on the dynamics of CO₂ emission from the surface of the exposed cultural layer obtained by the static chamber method.     

Application of the Succession Approach in Studying the Prokaryotic Community in Soils of East Antarctica

Prokaryotic communities of soils in oases of East Antarctica were studied at a model experiment with application of the succession approach. The total number of prokaryotes and filtered forms of prokaryotes, as well as the taxonomical diversity of the saprotrophic bacterial complex, were determined in two soil samples differing in organic matter content at temperatures of 5 and 20°C. We fixed the maximum total number of bacteria on the 14th day and the minimum number on the 1st and 160th (the end of the experiment) days in all variants. The amount and percentage of filtered forms of prokaryotes were the highest at the start of the experiment and the smallest on the 14th day. It is assumed that revival of Antarctica soils by humidification and incubation at temperatures above zero favors activation of dormant cells and their transition to viable status. Filtered forms of prokaryotes can be assigned to the pool of cells, which makes it possible to preserve bacteria at extremely low temperatures and without available water and nutrients. The succession approach enables more complete characterization of the taxonomic diversity of the saprotrophic bacterial complex and isolation of a wider genera of gram-negative bacteria than with a single inoculation of soil kept frozen. So it can be recommended for studying the prokaryotic community of Antarctica soils in model experiments.     

Organic matter accumulation by alkaline-constructed soils in heavily metal-polluted area of Subarctic zone

Journal of Soils and Sediments - The research aimed to investigate properties and functions of soils constructed from alkaline mining wastes of different origin to remediate the industrial barren...     

Anthropogenic evolution of dark gray forest-steppe soils in the southern part of the Central Russian Upland

A sequence of dark gray forest soils developing under a virgin broadleaved forest and under croplands used for 100 and 150 years was studied in the southern part of the forest-steppe zone on the Central Russian Upland. The application of multiple study methods for these objects made it possible to trace the evolutionary changes in the soil properties during the 150-year-long period of regular plowing. Several important trends in the soil development under the impact of the cultivation were revealed: (a) an increase in the thickness of the humus layer (according to the measurements at 20 points for each of the objects), (b) an increase in the amount of mole tunnels, (c) a decrease in the coefficient of the textural differentiation of the soil profile (with respect to the clay content), (d) an increase in the contents and reserves of the major nutrients upon a stable pool of humus in the upper meter, and (e) some alkalization and carbonization of the profile. Powdery accumulations of carbonates and whitish calcareous coatings on the faces of prismatic peds appeared at a depth of more than 130 cm. The plowed soils contained thin deep fissures, the surface of which was covered by dark-colored clayey-humus coatings at the depth of 50–110 cm. The radiocarbon age of the humus in these coatings was 500–1000 years younger than the age of the humus in the soil mass between the fissures. This set of features attests to the evolution of the plowed dark gray forest soils into chernozems under the impact of plowing.     

Soils of Archeological Landscape Sorokino 1 (Orel Oblast): Reconstruction of Natural Changes and Anthropogenic Transformation of the Environment

Eurasian Soil Science - Soil-archeological studies were performed in the area of the ancient Russian settlement Sorokino 1 dating back to the 13th century AD and located in the upper reaches of the...