Volume 71, Nº 4-5 (2016)

The widely used Munsell optical system is unsuitable for the statistical treatment of data for assessing the role of pigments in soil color. The CIE-L*a*b* system is more efficient for this purpose. This article contains a table for converting data on soil color from one scale to the other based on the example of oxisols (Brazil) and pale (Yakutia) and alluvial (Spain) soils. The advantages of the CIE-L*a*b* system for characterizing soil color have been shown.

The high degree of base saturation and high cation exchange capacity with an appreciable dominance of calcium are related to the high carbonate content in parent rocks, high content of humus in chernozems, and abundant fine material in their profiles. These are characteristic features of prevalent soils in the Kamennaya Steppe. Almost all soils of monitoring and experimental plots have an appreciable spatial variation in exchangeable bases. The obtained data indicate that the content of adsorbed calcium in the exchangeable complex of the soil decreases with increasing shares of adsorbed magnesium and partially sodium.

The contamination of heavy loamy chernozem by iron, sodium, magnesium, calcium, and hydrogen chlorides (2% of soil mass) decreases soil moisture content (W, percent of soil mass) in the interval of the soil moisture pressure (Р) from 0.0 to–0.6 atm, which indicate soil degradation. In a range of P from–0.2 to–0.6 atm, there is a close correlation between the logarithm of Р module (log|P|) and W and, therefore, a regression relationship log|P_W| = |P₀|–kW, where |P₀| and k are empirically determined parameters. This relationship is similar to the Landau–Deryagin law. The parameters |P₀| and k are also in a close correlation, which is described by the regression equation |P₀| = 29.3k–0.557. At chernozem contamination by chlorides, the |P₀| and k parameters become smaller, and so they may be used for the evaluation of degradation of chloride-contaminated soils.

The possibility of using the method of exhaustion (removal sampling) applied to determine the absolute number of Bacteria and Archaea populations in soil based on accounting data for quantitative fluorescence in situ hybridization has been shown.