卷 49, 编号 4 (2016)

A new soil map of the Russian Arctic on a scale of 1 : 1 M shows the soil cover in the north of Eurasia and on the islands of the Arctic Ocean to the north of 68° N. This map has been developed in a geoinformation system in the vector format with the wide use of remote sensing data. The delineated soil polygons show dominant and accompanying soils and the structure of soil cover patterns with indication of soil associations and soil complexes, the character of parent materials, and the topographic conditions. The map of the soil-geographic zoning of the Russian Arctic developed on the basis of the soil map differs from its earlier analogues in a greater degree of detail. The soil map of the Russian Arctic on a scale of 1 : 1 M displays the most detailed information on the soil cover patterns and can be used for solving various problems related to the exploration and development of this territory. Soil names from the new classification system of Russian soils [10] have been introduced into the legend of the map. New soil information and the use of remote sensing data have made it possible to enlarge the number of soil polygons shown on the map and to correct their boundaries in comparison with previous soil maps of the Russian Arctic.

The soil formation on noncalcareous loam under different phytocenoses in soil lysimeters (Soil Experimental Station of Moscow State University) for 49 years has led to a decrease in acidity and an increase in the content of organic matter, microelements, and heavy metals in the surface soil layer. The rate of microbial CO₂ emission and the microbial biomass content reached the maximum values under the mixed forest stand followed by the broad-leaved forest, then spruce forests, perennial grasses, and fallow. The minimum values of these parameters were characteristic of the black fallow. The percentage of C_mic in the organic carbon content of the soils under the broad-leaved forest was 2.7; in the mixed forest, spruce forest, fallow, and black fallow, it was 1.9, 1.2, 0.9, and 3.3, respectively. The maximum accumulation of heavy metals was recorded in the litter and at the depth of 2–15 cm. The Zn content in the soils under the woody vegetation was 18–20 times higher than in the parent mantle loam; in the soils under perennial grasses and in the plots without plants, it was 14–16 and 5 times higher, respectively. The biogenic accumulation and aerial dust transfer of heavy metals are responsible for the differences in their accumulation between the soils of the model phytocenoses and soils without vegetation. The content of elements in the dust exceeded that in the parent loam by 200–300 times for Zn, 20–40 for lead, 6–60 for nickel, and 20–30 times for strontium and barium. The composition and amount of dust determined the trends in these elements of accumulation in the soils.

The increased concentration of an element in plant biomass compared to the soil mass is an essential condition for the differentiated spatial distribution and status of the element on the aggregate level. Two forms of this differentiation have been revealed for ¹³⁷Cs and ⁹⁰Sr. Transfer of ¹³⁷Cs from plant roots and concentration on the surface of soil aggregates have been established experimentally. Indirect data also point to the potential localization of ¹³⁷Cs on the surface of intraaggregate pores. The effect of radionuclide concentrating on the outer and inner surfaces of aggregates is due to the rapid and strong fixation of cesium microamounts by mineral soil components. ¹³⁷Cs from the surface of aggregates is more available for the repeated uptake by plant roots than from the intraped mass. The distortion of this spatial differentiation mainly occurs during the reaggregation of soil mass, which in turn decreases the availability of the radionuclide to plants. For ⁹⁰Sr, its elevated concentration in the form of organic residues has been revealed in the inter- and intraaggregate pore space. However, due to the high diffusion rate, ⁹⁰Sr is relatively rapidly (during several months under pot experimental conditions) redistributed throughout the entire volume of soil aggregates and its major part gradually passes into the phase of humic compounds, to which the radionuclide is bound by exchange sorption. The high level of the next root uptake (higher than for ¹³⁷Cs by one to two orders of magnitude) favors the permanent renewal of loci with increased ⁹⁰Sr concentrations in the inter- and intraaggregate pore space in the form of plant residues.

The influence of long-term “dry” and “wet” climatic cycles on the water regime, hydrological parameters, and carbonate profiles of chernozems in Central European Russia and adjacent territories was studied. The hydrological and carbonate profiles were found to change during the wet cycle. However, the upper part of the hydrological profile is basically unchanging, whereas in its lower part, the number of hydrological horizons and contrast in their moistening decrease in the forest-steppe chernozems and increase in the steppe chernozems. The frequency of through wetting of chernozems increases during the wet cycles. The vertical lithological heterogeneity of the parent material affects the soil moisture status. In the wet climatic cycle, the moisture content above the lithological contact increases resulting in the development of the features of soil hydromorphism. In the carbonate profile, the character of pedofeatures is changing: some carbonate neoformations disappear, while the other ones develop. Possible variations of the periodically percolative water regime were revealed in chernozems. The classification of water regime proposed by A.A. Rode may be updated based on the data obtained during the dry climatic cycle. Rode’s hypothesis about cyclic variations in the soil water regime is confirmed.

General ecological and taxonomic characteristics of cyanobacterial–algal cenoses in ordinary chernozems under different ameliorative plants (phytoameliorants) were studied in the Trans-Ural region of the Republic of Bashkortostan. A comparative analysis of the taxa of studied cenoses in the soils under leguminous herbs and grasses was performed. The phytoameliorative effect of different herbs and their relationships with cyanobacterial–algal cenoses were examined. Overall, 134 cyanoprokaryotic and algal species belonging to 70 genera, 36 families, 15 orders, and 9 classes were identified. Cyanobacterial–algal cenoses included the divisions of Chlorophyta, Cyanoprokaryota, Xanthophyta, Bacillariophyta, and Euglenophyta. Representatives of Ch-, X-, CF-, and P-forms were the leading ecobiomorphs in the studied cenoses.

A new method has been proposed for simulating the development of a channel on sloping surface of an agrolandscape by the point source method. To study the direction and rate of channel development by the slope flow, it is proposed to take into consideration both the flow parameters and the gradient of erosion resistance potential, which represents the water flow energy necessary for the erosion of unit soil mass and its removal from the zone of its natural occurrence. The approach used makes it possible to restore the general situation from the experimental data. The proposed theoretical premises about the effect of the surface shape and state on the channel development have been confirmed by laboratory studies. From the results of these studies, a relationship of the channel development direction with the erosion resistance potential and the flow velocity has been derived.

A geoinformation database for assessing soil resource potential for horticulture in Krasnodar region and Adygea has been developed. The results of geoinformation analysis indicate that only 55–60% of soils in these regions are suitable for growing horticultural crops without limitations; about 35–40% of the total soil area is unsuitable for horticultural purposes. For plum trees, the area of unsuitable soils is somewhat lower than for other horticultural crops. Geographically, the areas of soils suitable and unsuitable for horticulture are close to one another. The thickness of the loose earthy soil material, the gravel content, the degree of salinization, the soil texture, and the degree of soil hydromorphism are the major soil properties imposing considerable limitations for the development of fruit-growing industry in the studied regions. The highest portions of soils suitable for horticulture are found in Eiskii, Kushchevskii, Krylovskii, Shcherbinovskii, and Novokubanskii districts of Krasnodar region. The development of horticulture in Tuapsinskii, Slavyanskii, and Primorsko-Akhtarskii districts is limited because of the unsuitability of soils for this purpose. About 8% of the existing orchards are found on soils recognized as unsuitable for horticulture, and only about 20% of the existing orchards are found on soils suitable for fruit growing without limitations. About 70% of the existing fruit orchards are located on degraded soils or on soils with certain limitations for horticulture. The profitability of fruit orchards on such soils is lower than that of the orchards planted on soils without limitations for horticulture. This information is necessary for the adequate economic evaluation of the degree of soil degradation.