Articles

The theoretical equation, based on the trace elements concentration in the soil as a function of depth and time, was deduced and tested on the experimental data on long-term dynamics of some heavy metals (copper, nickel, manganese) in soils of Moscow State University lysimeters under different types of vegetation.

The features of cesium-137 (137Cs) root uptake by spring oat (Avena sativa L.) and lettuce (Lactuca sativa L.) plants have been studied in a model experiment with simulation of radionuclide fallout into undisturbed monoliths of arable chernozems from the Plavsk radioactive spot. An integrated approach using digital autoradiography and γ-spectrometry methods has revealed a uniform pattern of vertical and lateral 137Cs distribution in the soil profile and low bioavailability of the radionuclide or root uptake by plants. Certain biological features of the test crops with respect to root uptake of 137Cs have been demonstrated: limited translocation of the element into shoots via its relative accumulation in roots for oats and limitation of general root uptake of 137Cs into plants, given its uniform distribution between roots and shoots for lettuce.

The possibility of using algorithm VERT_MIG the simulations of vertical migration of radionuclides in the soil are discussed. The algorithm was successfully used to develop models of migration 137Cs and 90Sr in radioactive contamination of different soils as a result of accidents at Chernobyl and Fukushima-1. The results of modeling are presented. The prospects for further use of this algorithm and some aspects of the use of simulation in this area are discussed.

Approaches used to assess the diversity of soils in Russia as well as algorithms of quantitative assessment of the differentiation of soil bodies and soil mantles are described. To assess soil diversity (or the degree of differentiation of materials from parent rocks into soil bodies and soil covers) two indices were introduced: index of vertical differentiation — Ird; index of spatial lateral differentiation — Ild (red). These indices were computed according to the structure of the soil cover on the Soil Map of the Russian Federation on a scale of 1 : 2.5 M within the spatial framework of the Map of Soil-Ecological Zoning of the Russian Federation on a scale of 1: 2.5 M. The most complex soil cover and soil profiles on plains were found for the zones of Soddy-podzolic soils (Umbric Albeluvisols/Umbric Podzols2) of southern taiga and Grey forest soils (Albic Luvisols/Luvic Greyic Phaeozems) of deciduous forests (they locate on the boundary of Boreal and Subboreal geographic belts and are characterized by wide spreading of dynamic-mature soils), as well as in mountains — for soil provinces in the Caucasus. Key words: pedodiversity, indices of differentiation, vertical differentiation of soils, lateral spatial differentiation of soil cover.

The evidence and factors of the formation of compact horizons in haplic chernozems are discussed. They include a complicated combination of agronomical consolidation, modern solonetzization, and residual alkalinity. It is shown that the combination of physicomechanical and chemical properties (high content of physical clay and clay fraction, low portion of aggregate openness and high interaggregate porosity, the presence of exchangeable sodium in the soil adsorbing complex, alkaline reaction (pH 8.3), mobility of the clay-humus fraction, etc.) favor the formation of overcompacted plow and subplow horizons and their dynamic stability independently of regular mechanical cultivation.

The features of the distribution of the stable isotope composition of carbon and nitrogen for saprotrophic and mycorrhizal macromycetes growing on an oligotrophic peatland were characterized for the first time. The molecular identification of the free-growing mycelium of mycorrhizal fungi detected the presence of both ecto- and arbuscular mycorrhizal fungi. Stable isotope composition of fruiting bodies and mycelium of mycorrhizal fungi of peatland differed fractionally. The fruiting bodies of saprotrophic fungi growing on the surface of the moss cover were enriched in ¹³С, but not in ¹⁵N, compared to their main substrate, sphagnum. Differences in the isotopic composition of functionally different parts of the fruiting bodies of macromycetes (hymenophores and stipes) were minor. The mycelium of mycorrhizal fungi of the peatland is enriched in ¹⁵N by 1,4 to 9,5 ‰ compared to the tissues of host plants. These values noticeably exceeds similar values, that were previously shown for forest ecosystems.