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Changes in carbon stocks and physical properties of gray forest soils during their postagrogenic evolution have been studied in the succession chronosequence comprising an arable, lands abandoned 6, 15, and 30 years ago; and a secondary deciduous forest (Experimental Field Station of the Institute of Physicochemical and Biological Problems of Soil Science, Russian Academy of Sciences, Pushchino, Moscow region). It is found that carbon stocks in the upper 60-cm soil layer gain with increasing period of abandonment, from 6.17 kg C/m on the arable land to 8.81 kg C/m in the forest soil, which represents the final stage of postagrogenic succession. The most intensive carbon accumulation occurs in the upper layer of the former plow (0- to 10-cm) horizon. It is shown that the self-restoration of gray forest soils is accompanied by a reliable decrease of bulk density in the upper 10-cm layer from 1.31 ± 0.01 g/cm on the arable to 0.97 ± 0.02 g/cm in the forest. In the former plow horizon of the arable-abandoned land-forest succession series, the portion of macroaggregates increases from 73.6 to 88.5%; the mean weighted diameter of aggregates, by 1.6 times; and the coefficient of aggregation, by 3.8 times. Thus, the removal of lands from agricultural use results in a gradual restoration of their natural structure, improvement of soil agronomical properties, and carbon sequestration in the upper part of the soil profile. [ABSTRACT FROM AUTHOR]

This article seeks to give counterarguments against the claims of some political scientists that Moscow continued to exercise control over the foreign-policy decision-making process in Bulgaria even after the country left the Soviet sphere of influence in the early 1990s. To this end, the term Russian factor is used in the light of Bulgaria's post-Communist "distancing" from the Russian Federation and its integration into the Euro-Atlantic community. Dwelling on some examples taken from the diplomatic practice of Sofia–Moscow bilateral relations, the author has tried to prove that soon after the end of the Cold War, the "Russian dominance" gave way to the much more attractive idea of Bulgaria's pro-Western spatial reorientation. [ABSTRACT FROM AUTHOR]

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In a moderately eroded regraded deep-podzolic clay loamy agrosoddy-podzolic soil (Albic Retisol (Loamic)) of unmanaged fallow in Moscow oblast, a significant increase in the content and reserves of total carbon has taken place after 22 years of its fallowing in comparison with the arable analogue. This increase has mainly been due to the rise in the carbon content of easily degradable organic matter (light fraction). The carbon content in the water-extractable organic matter from the fallow soil is also higher than that in the arable soil. The increase in the content of these groups of labile organic substances is apparently due to the amount and composition of plant residues entering the fallow soil, as well as a decrease in their mineralization compared to the arable soil. A significant increase in the content of the light fraction in the lower part of the arable field relative to its upper part has been found, which is associated with the transfer of light particles as a result of water erosion. In the fallow field, these differences are minimal. There has been a downtrend of the bulk and solid phase densities in the layer of 0–10 cm of fallow soil compared to arable soil due to the accumulation of plant residues in this layer. The fallow soil is characterized by a high content of agronomically valuable aggregates of 0.25–10 mm in size, water-stable aggregates, and large (>0.05 mm in size) microaggregates. [ABSTRACT FROM AUTHOR]