Articles

The analysis of experimental methods for assessing the cellulosolytic activity of soils and methods for calculating the results of its measurement are discussed basing on publications and authors' experiments. A brief overview of factors and dynamics of this phenomenon in soil profiles, including its seasonal changes, is presented, as well as information on its the geographic variability. The materials presented may be helpful for research in this area by emphasizing various details responsible for obtaining reliable results for interpretation.

The paper presents the results of the study of fatty acid profiles of typical chernozems with different management practice. The study showed that degradation of soil organic matter in typical chernozems is accompanied by depletion of fatty acids, while its accumulation resulted in an increase in their diversity. In this regard, the composition of fatty acid soil profiles allows classifying the soil successfully according to the prevailing processes of transformation of organic matter. An uneven distribution of fatty acids was discovered in soil aggregates of different sizes for the untillage chernozems, whereas arable chernozems possessed regular distribution of fatty acids among aggregates of different size. Eicosapentaenoic acid which is a moiety of microalgae, and dihomo-gamma-linolenic acid which is synthesized by fungi Mortierella can be considered as biomarkers of the withdrawal of typical chernozem from agricultural use to a fallow land.

The cause-and-effect relationships of the land degradation processes occurred under the different agricultural use were defined and estimated based on the study of soils of the Akhty mountain and valley agricultural experimental station. The concept of DPSIR (Driving forces-Pressure-State-Impact-Response) revealed that the main factor in increasing the degradation of soils of the station is a socio-economic factor.

On the basis of a detailed study of the vegetative-detrital cover (VDC) of pine ecosystems of the Mari Zavolzhye, it is shown that, depending on its genesis, a specific hydrothermal regime of soils is formed in each type of forest. It has been established that the VDC has the highest moisture capacity in lichen pine-mossy pine forests in comparison with lichen pine forests. For the first time, based on the parameters of the VDC, a scale was proposed for estimating the rate of the biological cycle. It is established that the most important indicators are the power of the VDC, ash content and hydrolytic acidity.

Изучены действие и последействие строительства трассы магистрального трубопровода на свойства гумуса и особенности его распределения по гранулометрическим фракциям дерново-подзолистой почвы. Охарактеризованы признаки техногенной деградации гумуса и степень их выраженности по сравнению с контрольной почвой в разные периоды наблюдений во взаимосвязи со спецификой экологической ситуации.

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.