Vol 72, No 1 (2017)

Specific features of the structure and composition of the soil cover in the Salym-Irtysh interfluve, Western Siberian Lowland, are studied with consideration of the capabilities of digital mapping. The properties of predominating and accompanying soils, which determine the modern status of boreal landscapes, are evaluated. Aspects of genesis and the Quaternary history of the investigated region are analyzed by a comparative approach. Possible trends of soil-plant cover transformation under climate changes are discussed.

Color is an important physical property in the diagnosis of soils and the description of soil profiles. Quantitative data from spectrophotometers and colorimeters have been used in soil studies for this purpose, but Munsell color description remains the main method of soil color evaluation. Low cost digital devices (cameras) could largely replace the semi-quantitative assessment of color yielded by Munsell charts, so long as they can be colorimetrically characterised to yield accurate and reproducible data. In this study, we explore the feasibility of using a digital camera to derive colorimetrically accurate images and data of 136 soil samples, using soil chart for calibration. Accurate color characterization can be achieved (ΔE_ab* color errors of <3) for 84% of studied soil samples, highlighting the merit of this rapid and low cost approach for soil color evaluation.

The texture of bottom sediments of the Bureya River and its tributaries in the region of the Lower Bureya HPP is studied by sieve analysis, laser diffractometry, optical microscopy, and X-ray fluorimetry. It is found that the texture of sediments in the studied area varies from pebble to silt. Sediments of the Bureya River tributaries mainly consist of fine earth (particle diameter <2 mm). Fine earth in the Bureya River is more transformed, sorted, and represented by significantly smaller particles than in the tributaries. In contrast to bottom sediments, suspension sediments are similar in particle size. The studies reveal that the bottom sediment composition corresponds to the genesis of the river basin rocks, although differences in the bulk composition of sediments are not observed on the texture level.

The results of a model laboratory experiment in which the acidic oil-polluted sand was incubated for three months in the presence of palygorskite or bentonite clays supplemented with mineral fertilizers and lime under conditions of periodic wetting and drying are presented. A reliable decrease in the total content of nonpolar and weakly polar CCl₄ extractable organic compounds and of the weakly polar compounds was established. The content of the nonpolar fraction, the amount of C₁₄–C₃₆ alkanes in its composition, and the (C₁₇ + C₁₈)/(C_i–15 + C_i–16) ratio, which was indicative of microbiological destruction of hydrocarbons, decreased significantly in the experiment with the palygorskite clay.