Articles

In Russia, the lands with oil contaminated soils exceed tens of thousands hectares. However, to date, there were no unified approaches to the rationing of oil and petroleum hydrocarbons (PH) in soils, a guideline to choose optimal evaluation indicators. The response of plants in the pot experiment could provide significant results for assessing and rationing of PH content in soils and their use in agriculture after land remediation. In this work we assessed the response of higher plants as a marker of the direction and intensity of biological processes in soils in the pot experiment under oil contamination to justify the standards of permissible residual content of PH in soils of agricultural lands. The composition and properties of Luvic Chernozems, Calcic Chernozems, Voronic Chernozems (WRB, 2015) used in the pot experiment, which was carried out in a month after the soil contamination with crude sulfur-containing oil, were investigated. The effect of different oil doses on the bioproductivity of wheat and peas was evaluated. Wheat in terms of dry biomass showed higher sensitivity to PH, containing medium and heavy fractions, than peas. Rationing the PH content in chernozems, a nonlinear regression model described by a logistic curve was applied. The quality standard values found for wheat biomass was 0,9; 0,4; 1,0 g * kg^-1 for Luvic Сhernozems (humus content ~ 9,8%, sandyloam texture); Calcic Chernozems (humus content ~7,6%, clay loam texture), Voronic Chernozems (humus content ~12.8%, loam texture), respectively. The residual PH contents, found as 30% of soil functioning change, which corresponded to the risk level of soil degradation, estimated by the soil fertility parameter — dry wheat biomass were 1,2 g·kg^-1 for Voronic Chernozems; 0,5 g·kg^-1 — Calcic Chernozems; 1,1 g·kg^-1 in Luvic Chernozems.

New indicators of lanthanide affinity for carrier phases in the soil, based on the rationing of lanthanide concentrations by their soil clarks, are proposed. This made it possible to obtain an original indicator of the affinity of lanthanide A_LN to carrier phases in soils. The indicator of affinity of lanthanide A_LN showed its advantage over the accepted pC_Ln index in the analysis of Russian and Swedish soils.

Salt neoformations in sandy and silty loam soils of the Aral Sea dried bottom in the south-western part were studied by X-ray fluorescence, electron microscopic, sedimentation methods of analysis and laser diffractometry. The surface layers of soils are significantly saline and enriched with CaCO₃. The distribution of CaCO₃ over the area is quite uniform, which indicates relatively close conditions of its formation during desiccation. The salt content varies from 0.4 to 1.2% in sands and from 3.1 to 5.8% in silty loam. The latter are characterized by the highest salinity, when, in addition to gypsum and halite, readily soluble salts are formed: eugsterite (2Na₂SO₄^.CaSO₄.2H₂O), astrakhanite (Na₂SO₄^.MgSO₄^.4H₂O), and mirabilite (Na₂SO₄^.10H₂O). Precipitation of calcite upon drying leads to the formation of CaCO₃-ooids in sands and CaCO₃- microaggregates from clay and silty particle in silty loam. The reason for the increased activity of easily soluble salts in the processes of aeolian transport has been established. This transport and, correspondingly, the salinization of adjacent territories are facilitated by the blocking of adsorption centers in clays by calcite, which prevents the binding of easily soluble salts in clay-salt microaggregates.

We present a review of the literature data and the results of our own studies on the influence of soil invertebrates of the macrofauna size class on the processes of creating and maintaining the heterogeneity of soil properties in the temperate zone. Significant changes in physical, chemical and biological parameters of soils, compared with background indicators, were noted in excrement and associated soil aggregates, as well as substrates — products of vital activity of key groups of large invertebrates, such as earthworms, diplopod millipedes, diptera and coleoptera larvae, woodlice, and ants. Most of the research is related to the impact of earthworms and ants on soils, whereas for other groups few reports exist. The results of the research will be useful for practical purposes, in particular for the development of sustainable anthropogenic ecosystems.

Methodological aspects of identification, accounting, analysis of development and interaction of soil heterogeneities of various genesis are considered. The modern views on their origin are summarized, methodigical approaches and features of the study are shown. Conceptual views in the field of soil science are presented, which allow a deeper and more comprehensive approach to the assessment of such a phenomenon as soil heterogeneity: the hierarchical orga- nization of soil space, historical and modern («soil-memory» and «soil-moment») components of soil heterogeneity, soil succession and their role in understanding the essence of the phenomenon under consideration. The concept of primary and secondary heterogeneities is formulated, which are defined as a universal feature that manifests itself at all levels of the organization of the soil space and is formed, respectively, by paleo- and cenotic mechanisms. It is shown that the primary heterogeneity is the result of the action of pedogenesis factors, which reflects the desire of the soil to find an equilibrium state with the environment. Secondary heterogeneity is a consequence of the action of various natural and anthropogenic factors that bring the soil system out of equilibrium. A scheme of factors and causes of primary and secondary heterogeneities is proposed and formalized, as well as a scheme of modern factors and causes leading to the emergence of secondary heterogeneity of various origins. The priority role of the works of E.A. Dmitriev and his school in the formation of modern views on the heterogeneity of soils, in the development of field and statistical methods for analyzing the assessment of this natural phenomenon, which he put in a number of direct objects of research, is emphasized.

Th e article discusses the current approaches to the assessment of the heterogeneity of soil properties. On the example of the experimental plot (106 ha) of the RUNE “Grodno Zonal Institute of Plant Industry of the National Academy of Sciences of Belarus” it is shown that ignoring the intra-fi eld heterogeneity leads to even more signifi cant diff erences. On the experimental fi eld, using satellite images and multi-temporal indices EVI, microplots with an area of 50 to 200 m2 with а signifi cantly reduced level of eff ective fertility, up to the death of plants, were identifi ed, on the basis of which а sampling grid was developed. During the fi eld work, 214 pHKCl samples were taken with а sampling step of 70 m and 53 additional samples in the “problem areas”. Using geostatistical methods, data on the spatial heterogeneity of pHKCl were obtained, the degree of spatial dependence and the accuracy of the results obtained were estimated for various numbers of samples (107, 216, and 268 points). Further use of stochastic modeling made it possible to construct high-precision cartograms of acidity with а pixel resolution of 4 m and 12 m. We also showed that the use of cell sizes less than the processing device is not useful for solving applied issues of precision farming. Probabilistic-statistical models were obtained, represented by cartograms of mean square errors and the probability of the phenomenon. Th e resulting cartograms showed the presence of ultra-acidic soils in the “problem zones”; such а reaction also determines the presence of toxic aluminum compounds and extremely low calcium and magnesium contents, which jointly lead to the absence of seedlings of cultivated vegetation. А detailed accounting of soil acidity in comparison with а classical agrochemical survey provided savings of $ 2807 by the application of СаС03, which made it possible to fully compensate for the additional costs of taking and analyzing а larger number of samples.

The regularities of the spatial distribution of ¹³⁷Cs in forest soil at the microlandscape level in semiromophic and hydromorphic conditions in the Bryansk region at different measurement steps with the KORAD radiometer (10, 2 and 0,5 m) are investigated. The variability of the ¹³⁷Cs stock obtained by two devices differing in the size of the sampling area (RPO) is compared: 1) CORAD radiometer 2) sampler D=14 cm. The ratio of the variability of the ¹³⁷Cs distribution obtained by field radiometry to the sampling data (CVcorad/CV sample) for the entire site is 0,63; for the hydromorphic part, B1-1 is 0,87. For the entire site (size 50x80 m), a weak spatial correlation was revealed (the effect of a "chessboard"), for a local hydromorphic site, a strong correlation with a rank of 1,4 m.

The aim is to present statistical portrait of soil cover pattern for farm as series of cumulative statistical distributions of soil horizon’s depth and thickness. The object is soil combinations of Haplic or Luvic Protosodic Kastanozems and Solonetzs at the experimental station “Irrigated” localized in southern-western end of the Volga Upland near the Volga-Don Channel. Majority of empirical statistical distributions of soil horizon’s depth for general data fetch (182 profiles) cannot be approximated by normal one. Nonparametric indices are used. Separation of soil groups using substantial properties does not guarantee data fetches with normal distribution for all morphometric properties. Soil types and subtypes according to Russian soil classification system have different complex of statistical distributions of soil horizon’s depth. Many differences are related to changes of carbonate profile, development of secondary solonetzicity, crust formation, local surface washout and accumulation of upper part of arable horizon.