Solonetzic Soils Research Articles

The sensitivity of water extractable soil organic carbon fractions to land use in three soil types

ABSTRACTSoil organic carbon (SOC) has a high impact on the sustainability of ecosystems, global environmental processes, soil quality and agriculture. Long-term tillage usually leads to SOC depletion. The purpose of this study was to determine the impact of different land uses on water extractable organic carbon (WEOC) fractions and to evaluate the interaction between the WEOC fractions and other soil properties. Using an extraction procedure at 20°C and 80°C, two fractions were obtained: a cold water extractable organic carbon (CWEOC) and a hot water extractable organic carbon (HWEOC). The results suggest that there is a significant impact from different land uses on WEOC. A lower relative contribution of WEOC in SOC and a lower concentration of labile WEOC fractions are contained in arable soil compared to forestlands. Chernozem soil was characterized by a lower relative contribution of WEOC to the SOC and thus higher SOC stability in contrast to Solonetz and Vertisol soils. Both CWEOC and HWEOC are highly associated with SOC in the silt and clay fraction (<53 µm) and were slightly associated with SOC in the macroaggregate classes. The WEOC fractions were highly and positively correlated with the SOC and mean weight diameter.

Экономическая эффективность возделывания яровых зерновых культур при предпосевной инокуляции микробиологическими препаратами в различных почвенных условиях Астраханской области

В настоящее время для получения высоких и устойчивых урожаев растениеводческой продукции наряду с эффективными агро- и фототехническими приемами необходимо широко применять биологические препараты — бактериальные удобрения на основе полезных групп микроорганизмов и разные виды микроудобрений. В статье приведены основные результаты изучения урожайности и экономической эффективности вложенных затрат при использовании биопрепаратов на основе ассоциативных азотфиксирующих микроорганизмов на яровые зерновые культуры в различных почвенных условиях Астраханской области. Для выявления эффективности различных препаратов в зависимости от сорта или генотипа сельскохозяйственных растений рекомендуется проводить исследования в мелкоделяночных опытах, так как это позволяет при минимальных затратах получать информацию об эффективности биопрепаратов. Из всех изучаемых микробиологических препаратов наилучшие экономические показатели получены у яровой пшеницы сорта Саратовская 70 в вариантах с предпосевной инокуляцией препаратами Агрофил и Ризоагрин, у ярового ячменя сорта Нутанс 553 — в вариантах с препаратами Флавобактерин и Мизорин как в условиях светло-каштановой солонцовой, так и на бурой полупустынной почве. Максимальная экономическая эффективность вложенных затрат при возделывании ярового ячменя Нутанс 553 получена в условиях светло-каштановой солонцовой почвы в варианте с предпосевной инокуляцией препаратом Мизорин и составила 2,14 руб./руб.; при возделывании яровой пшеницы Саратовская 70 (так же в условиях светло-каштановой солонцовой почвы) — в варианте с использованием микробиологического препарата Агрофил — 1,90 руб./руб. Показатели по данным препаратам в условиях бурой полупустынной почвы были немного ниже.

Ion association in water solution of soil and vadose zone of chestnut saline solonetz as a driver of terrestrial carbon sink

Abstract. The assessment of soil and vadose zone as the drains for carbon sink and proper modeling of the effects and extremes of biogeochemical cycles in the terrestrial biosphere are the key components to understanding the carbon cycle, global climate system, and aquatic and terrestrial system uncertainties. Calcium carbonate equilibrium causes saturation of solution with CaCO3, and it determines its material composition, migration and accumulation of salts. In a solution electrically neutral ion pairs are formed: CaCO30, CaSO40, MgCO30, and MgSO40, as well as charged ion pairs CaHCO3+, MgHCO3+, NaCO3−, NaSO4−, CaOH+, and MgOH+. The calcium carbonate equilibrium algorithm, mathematical model and original software to calculate the real equilibrium forms of ions and to determine the nature of calcium carbonate balance in a solution were developed. This approach conducts the quantitative assessment of real ion forms of solution in solonetz soil and vadose zone of dry steppe taking into account the ion association at high ionic strength of saline soil solution. The concentrations of free and associated ion form were calculated according to analytical ion concentration in real solution. In the iteration procedure, the equations were used to find the following: ion material balance, a linear interpolation of equilibrium constants, a method of ionic pairs, the laws of initial concentration preservation, operating masses of equilibrium system, and the concentration constants of ion pair dissociation. The coefficient of ion association γe was determined as the ratio of ions free form to analytical content of ion γe = Cass∕Can. Depending on soil and vadose zone layer, concentration and composition of solution in the ionic pair's form are 11–52 % Ca2+; 22.2–54.6 % Mg2+; 1.1–10.5 % Na+; 3.7–23.8 HCO3−, 23.3–61.6 % SO42−, and up to 85.7 % CO32−. The carbonate system of soil and vadose zone water solution helps to explain the evolution of salted soils, vadose and saturation zones, and landscape. It also helps to improve the soil maintenance, plant nutrition and irrigation. The association of ions in soil solutions is one of the drivers promoting transformation of solution, excessive fluxes of carbon in the soil, and loss of carbon from soil through vadose zone.

Development of erosional microforms and soils on semi-natural and anthropogenic influenced solonetzic grasslands

The rate of berm erosion and its effect on soil properties and vegetation were investigated at two sampling plots, one semi-natural and the other heavily affected by anthropogenic influences, between 1998 and 2012. The two sampling areas are similar in terms of natural characteristics, and adjacently located in the Hortobágy, a very flat plain with Solonetz soils. In the course of berm-formation, both erosion and deposition take place within a few meters' range, so we were able to obtain the rate of each process for both experimental plots. The erosion rates of the DS plot under semi-natural conditions, and the MS plot affected by anthropogenic influences, were 1.99 and 4.49kgm−2year−1, respectively, and the rate of deposition were 2.12 and 2.78kgm−2year−1. The recession speed of the berm edges was determined to be 10±3mmyear−1 for the DS plot and 26±8mmyear−1 for the MS plot. During the period of our investigation, all the calcium-carbonate content, pHH2O, pHKCl, electrical conductivity (EC1:2.5), exchangeable cation content (Σcations), and exchangeable Na percentage (ESP) of the soil in the MS plot showed significant changes, whereas in the soil of the DS plot only EC1:2.5 and Σcations changed significantly. Both EC1:2.5 and Σcations decreased in both soil profiles. At the DS plot, ESP did not change substantially, whereas at the MS plot it increased significantly.The results of the experiments revealed that in the course of berm erosion, the rates of the spatially extremely versatile, mosaic-like erosion and deposition processes show significant differences even within a small area, depending on environmental influences. Although this tendency may only prevail over shorter distances because of the exceptionally low relief energy, and can be balanced out in larger spatial ranges, both erosion and deposition are considerably more intensive and accelerated in areas affected by anthropogenic influences.

Анализ экономической эффективности технологии возделывания озимой пшеницы с применением стимуляторов роста на примере светло-каштановой солонцовой и бурой полупустынной почвы Астраханской области

Одной из первоочередных задач, стоящих перед аграрной наукой — разработка энергоресурсосберегающих технологий выращивания сельскохозяйственных культур, внедрение которых обеспечит получение конкурентоспособной продукции. В многолетнем опыте в условиях светло-каштановой солонцовой почвы Черноярского района и бурой полупустынной почвы Енотаевского района Астраханской области изучали воздействие внекорневых подкормок стимуляторами роста при возделывании озимой пшеницы сорта Донщина. Полевой опыт закладывали на орошаемом участке. В качестве стимуляторов роста для растений озимой пшеницы были определены Плантафол, Мегафол, Мастер и Лигногумат. Экономическую эффективность рассчитывали на основе сопоставления количественных и качественных показателей изучаемых технологий с контролем в соответствии с зональными рекомендациями по возделыванию зерновых культур. Расчет экономической эффективности показал, что производственные затраты при возделывании озимой пшеницы с использованием комплексных стимулирующих удобрений в расчете на 1 га изменялись в зависимости от вариантов внекорневых обработок, а затраты на единицу продукции напрямую зависели от величины урожайности. Обработка посевов в фазы кущения, трубкования и цветения не привела к существенному увеличению производственных затрат, но окупилась дополнительной продукцией, что отразилось на урожае. Результаты проведенных исследований 2010 – 2013 гг. показали, что максимальная урожайность и прибавка урожая на всех изучаемых вариантах исследований была получена в условиях бурой полупустынной почвы Енотаевского района Астраханской области. Экономическая эффективность по аналогичным технологиям возделывания озимой пшеницы сорта Донщина в условиях светло-каштановой солонцовой почвы (суглинок средний) по сравнению с бурой полупустынной почвы (супесь) менее эффективна, что было доказано невысокой урожайностью.

Защитно-стимулирующие свойства микробиологических препаратов при возделывании ячменя на примере светло-каштановых солонцовых почв

Защитно-стимулирующие свойства микробиологических препаратов при возделывании ячменя на примере светло-каштановых солонцовых почв

COMPREHENSIVE ANALYSIS OF THE MICROBIOME IN THE COMPLETE PROFILE OF VIRGIN LIGHT-COLORED SOLONETZ SOIL AT THE TERRITORY OF DZHANYBEK EXPERIMENTAL STATION

Under study was the microbiome structure in virgin light-colored hydromorphized solonetz soil by using molecular-genetic and cultural methods. It was shown that the diversity of the microbial community is constantly decreasing down the soil profile being sharply declined in the solonetz horizon. Against the background of decreasing the biodiversity some groups of Proteobacteria are prevailed in the solonetz horizon and in the lower part of the profile. An unusually higher share of Crenarchaeota (almost 20% of the community) is observed in the topsoil.

CYTOGENETIC ASSAY OF CENOPOPULATION OF KOCHIA PROSTRATA IN KALMYKIA

The article presents data on cytogenetic research of cenopopulation of a Kochia prostrata in the range of large morphostructure of the Republic of Kalmykia. Considering lack of consensus concerning classification of the Kochia prostrata, a study of chromosome number of karyotypes aimed at bringing in cytogenetic features is carried out in this work for an explanation of intraspecific differentiation of Kochia prostrata on morphological features. For fixation of material, coloring of chromosomes and preparation of cytologic smears the standard methods modified in relation to the Kochia prostrata were used. The number of chromosomes of the Kochia prostrata was calculated in mother cells of microspores. Thus, when studying the number of chromosomes in mother cells of pollen in meiosis in 7 cenopopulations of Kochia prostrata, the karyotypic groups with different number of chromosomes are revealed: 2n = 18, 2n = 36, 2n = 54. Furthermore, karyotypic group was associated not with a morphostructure, but with the soil type. 36-chromosomal cenopopulation, for instance, were associated with light brown and dark-chestnut solonetzic soils, 18-chromosomal cenopopulation - with light brown soils of higher salinity level, 54-chromosomal cenopopulation - with brown desert-steppe soils of different salinity level. The revealed differences of cenopopulation of the Kochia prostrata in number of chromosomes testify to deep intraspecific differentiation. It is not excluded that the revealed chromosomal forms are representatives of different types. For a complete proof of this assumption it is necessary to conduct additional researches on hybridization of these objects.

Invertebrates of the cheegrass steppe in solonetzic soils of Transbaikalia: Spatial and time structure

The structure, dominant groups, and the features of invertebrates’ spacetime distribution have been defined as a result of soil and zoological studies in the cheegrass (Achnatherum splendens (Trin.) Nevski) steppe on solonetzic soils in Transbaikalia. Poor taxonomic diversity and small number and biomass of invertebrates are the peculiarities of the zoological complex. Factors that limit the activity of invertebrates are detected: poor botanical composition, adverse conditions of heat and moisture exchange in the soil, and its physical and chemical properties and salinity. A study of the spatial distribution of invertebrates show that Achnatherum is the basic edificator of the community. In Transbaikalia, two main types of invertebrate communities are formed depending on the seasonal amount of precipitation: desert-steppe and meadow-steppe. The diversity and abundance of invertebrates caught in soil traps positively correlated with precipitation and negatively with temperature. The size of the cheegrass root system has the greatest impact on the distribution of invertebrates in the soil.

Increased profile wettability in texture-contrast soils from clay delving: case studies in South Australia

Clay delving is becoming a popular practice to increase productivity of texture-contrast soils in southern Australia. The practice brings subsoil clay to the surface to be mixed with the sandy topsoil, and unlike clay spreading, it combines the addition of hydrophilic material with a ripping effect that disrupts the sharp boundary between the sandy topsoil and clayey subsoil. Our objective was to evaluate the magnitude of effects caused by delving on the spatial distribution of water through the profile for three Sodosols (Stagnic Solonetz soils) in the south-east of South Australia. We also wished to evaluate the extent to which clay delving might reduce water ponding at the A–B horizon interface. We wetted both delved and undelved texture-contrast soils with a Brilliant Blue dye solution under initially dry and wet conditions (to evaluate the effect of antecedent water content), and then took digital images of the stained profiles for quantitative comparison of the wetted areas. The stained soil profiles indicated that clay delving reduced preferential water flow (finger flow) and resulted in deeper and more uniform wetting of the A horizon, particularly under initially dry conditions. Under wet conditions (where water repellence was largely overcome), finger flow was significantly reduced regardless of delving but it still occurred to varying degrees depending on site characteristics. Delving significantly reduced ponding of water at the A–B horizon boundary and allowed greater penetration into the B horizon. At all sites, greater effects occurred directly on the delving lines and diminished with distance, implying that closer spacing of delving tines would increase uniformity of wetting throughout the profile. The effectiveness of delving on profile wetting was highly variable across the three sites, indicating that the outcome depends inter alia on the intrinsic soil characteristics and the delving equipment used in the field.

Long-term changes in soil salinity as influenced by subsoil thickness in a reclaimed coal mine in east-central Alberta

Olatuyi, S. O. and Leskiw, L. A. 2014. Long-term changes in soil salinity as influenced by subsoil thickness in a reclaimed coal mine in east-central Alberta. Can. J. Soil Sci. 94: 605–620. Elevated salinity and sodicity are major challenges to reclamation of surface-mined coal sites in the Alberta Plains region. Research plots were established in 1981 at the Battle River Coal Mine near Forestburg, AB, to determine an optimum depth of subsoil replacement over sodic mine spoil required to sustain agricultural capability. Subsoil thickness was varied at 0, 25, 65, 135, 165 and 335 cm, overlain with 15 cm topsoil. The plots were monitored annually from 1982 to 1986 and were seeded to forage from 1987. Plots were resampled in 2013 to examine long-term changes in soil quality by comparing the results with the historical means for the 1980s. Key soil parameters measured are pH, electrical conductivity (EC), total dissolved salts (TDS), sodium adsorption ratio (SAR) and soluble Na. The soil quality of the root zone (0–40 cm) improved over time in all treatments as EC, TDS, SAR and concentration of Na decreased significantly between the 1980s and 2013. Amounts of EC and soluble Na consistently increased with depth, suggesting salt accumulation was predominantly by downward leaching, but with contribution by upward migration of Na from the underlying spoil. Relative to the native soils in 2013, the root zone quality ratings for EC and SAR in the topsoil/spoil treatment were better than in the shallow-bedrock Solonetzic soil. Ratings for the 25-cm subsoil treatment were also comparable with the local Chernozemic soil, but better than the fine till Solonetzic soil. This study demonstrates that a minimum of 25 cm subsoil and 15 cm topsoil are required for mitigating salinity and sodicity in these reconstructed soils. The resampling in 2013 demonstrates that long-term monitoring is essential to obtain a better understanding of reclamation outcomes.

Soil classification groups to quantify primary salinity, sodicity and alkalinity in South African soils

This study aimed to quantify the primary salinity, sodicity and alkalinity of South African soils based on soil classification groups and rainfall classes, by using available analysed data. The 73 soil forms used by the Soil Classification Working Group were organised into 11 groups based on the occurrence of specific horizons. Soil analyses of 12 552 profiles for pHwater, 11 712 profiles for electrical conductivity, and 12 174 profiles for exchangeable sodium and cation exchange capacity were used. Median and not average values best represented salt-affected soil data on a national scale, because most data was strongly positively skewed. Primary soil alkalinity and sodicity were more common than primary salinity in terms of the different South African soil groups. None of the soil groups were saline, only the prismacutanic group was sodic, while the calcic, alluvial/aeolian, neocutanic and prismacutanic groups were alkaline when the median value or highest value in a profile was used as indicator. Sufficient data was not available, even for this relatively large dataset of 648 prismacutanic B-horizons, to proclaim a precise exchangeable sodium percentage value as a criterion for prismacutanic or solonetz soils in South Africa. Salinity, sodicity and alkalinity decreased as rainfall increased due to the depletion of cations and anions. The incidence of salt-affected soils in the soil classification groups decreased in the order: calcic ≥ alluvial/aeolian > prismacutanic > vertic > pedocutanic/red structured > neocutanic > hydromorphic ≥ lithosols > plinthic > apedal > podzolic. This information serves as an indicator of the primary sodicity and alkalinity of South African soils and can be utilised to deduce the expected sodicity and alkalinity of soils from soil survey data, to monitor anthropogenic sodicity and alkalinity impacts, and as an input to map the primary sodicity and alkalinity of South African soils.

Concretions in typical chernozem, gleyed chernozem-like, and solonetzic chernozem-like soils of the southern Tambov Lowland

A system for the diagnostics of chernozemic soils of the Tambov Lowland based on concretions is proposed for agricultural and reclamation purposes. The relationships between the structure and composition of the carbonate concretions, the long-term water regime of the soils, and the productivity of the crops have been established. The dense concretions in the typical chernozem testify to the depth of the seasonal wetting; the angular-rounded concretions in the deeply gleyed chernozem-like soil, to the upper boundary of the capillary fringe; and the angular concretions with sharp edges and cavities in the gleyic chernozem-like soils, to the groundwater table. In the chernozem-like soils that were waterlogged with bicarbonate-sodium water, the black angular concretions were formed in the solonetzic horizons, while the weakly compacted light-colored ones, in the zone of the capillary fringe. Humic acids were responsible for the color of the dark neoformations, and fulvic acids predominated in the light-colored ones. The appearance of black fine nodules indicated periodic surface water stagnation. Manganese predominantly accumulates in these nodules. The structure of the Mn-Fe concretions in the plow horizon observed at a magnification of 40–50 times has a diagnostic importance. The short-term (2–3 weeks) water stagnation leads to the formation of fine-stratified concretions, and the long-term (up to 1.5 months) stagnation promotes the formation of uniform porous ones. The solonetzic process induced by the bicarbonate-sodium water results in the appearance of mottled concretions.

Changes in the properties of soils in a solonetz soil complex thirty years after reclamation

The long-term (30 year) dynamics of a solonetz soil complex composed of solonetzic light chestnut soils and chestnut solonetzes under standard conditions and with the application of agromeliorative measures are considered. When the standard zonal agricultural practice is used, the soils of the solonetzic complex have unfavorable agrophysical, chemical, and physicochemical properties and low productivity. After 30 years of the standard three-level tillage of the soils to a depth of 40–45 cm, the productivity of the biogeocenosis decreased. Thirty years after a single rotary-milling subsoil treatment of the 20- to 45-cm soil layer using a milling tool FS-1.3, there were no morphological features pointing to the restoration of the solonetzic process. The humus content in the 0-to 20-cm and 20-to 40-cm soil layers was 2.3 and 1.7%, respectively; the content of adsorbed Na+ in the 20-to 30-cm layer was 11.6% of the total exchange capacity, or 38% lower than its content in the reference soil. The additional yield reached 30–70% and more of that obtained with the standard agricultural technology used during the whole period under investigation. The method of systems biogeotechnology (systems bio-geo engineering) is proposed as a method for the preventive control of soil evolution and the maintenance of the stability and high productivity of the soil cover.

?HEMICAL EQUILIBRIUM OF SOIL SOLUTION IN STEPPE ZONE SOIL

Dynamics of material composition, migration and accumulation of salts is determined by chemical equilibrium in soil solution. Soil solution contains associated electrically neutral ion pairs CaCO30; CaSO40, MgCO30, MgSO40, charged ion pairs CaHCO3+, MgHCO3+, NaCO3-, NaSO4-, CaOH+, MgOH+. Calculation method is proposed for quantitative assessment of real ion forms in the soil solution of chestnut solonetz soil complex. Were proposed equations to calculate free and associated forms of ions. To solve the equations were used an iteration, a linear interpolation of equilibrium constants, a Method of Ionic Pairs including a law of initial concentration preservation, a law of the operating masses of equilibrium system, the concentration constants of ion pair dissociation on the law of operating masses. Was determined the quantity of ion free form and a coefficient of ion association as ratio of ions free form to analytical content I³e = Cass/Can. The association of ions varies in individual soils and soil layer. Increasing soil solution salinity amplifies the ions association. In form of ionic pairs in soil solution are: 11.8-53.8% of Ca2+; 9.4-57.3% of Mg2+; 0.7-11.9% of Na+; 2.2-22.3% of HCO3-, 11.8-62.7% of SO42-. The ion CO32- is high associated, the share of ions in associated form is up to 92.7%. The degree of soil solution saturation was obtained for three level of approximation accounting on analytical concentration, calculated association coefficient, calculated coefficient of association. Relating to thermodynamic solubility product S0, the mathematical product of analytical ionic pairs indicated super saturation of soil solutions up to K1 = 100, taking into account calculated coefficient of association ion activity super saturation of soil solutions is absent, K3≈1. Only for solonetz chestnut meadow K3≈2-5. The soil solution saturation degree in soil profile and laterally in landscape varies. The quantitative assessment of real ion forms in the soil solution allows explain evolution of landscape of salted soils, structure of soil cover. Calculations fulfilled show that a possibility of soil degradation scenario taking into account the laws of association of ions in soil solution is much more probable and dangerous than it was assessed before. New understanding of water-salt transfer, geochemical barriers and ecological functions of soil will help to improve rainfed and irrigational agriculture.

Distribution of carbon and nitrogen in water-stable aggregates and soil stability under long-term manure application in solonetzic soils of the Songnen plain, northeast China

Excessive exchangeable sodium and high pH significantly decrease soil structural stability and permeability. Long-term application of cattle manure is an important management practice that can affect water-stable aggregates (WSAs), as well as aggregate stability and distribution of soil organic carbon (SOC) and total nitrogen (TN) in solonetzic soils. Experiments were carried out in a randomized complete block design comprising five treatments according to the cattle manure application history: corn (Zea mays) with manure applied for 1, 5, 12, and 17 years were used as the experimental treatments and corn without manure application was used as a control. Soil properties, including WSAs, mean weight diameter (MWD), and SOC and TN concentrations in bulk soils and WSAs, were measured across all treatments. The relationships among the measured soil attributes were determined using stepwise regression analysis. Results indicated that micro-aggregates mainly accumulated in soils without manure application, while manure application significantly increased macro-aggregates formation. MWD was highest when manure was applied to the soil for 1 year, decreased after 5 years, and increased again after 12 years. SOC and TN concentrations in bulk soils and WSAs increased with the number of years of manure application, with the highest concentrations observed for 17 years in bulk soils. Stepwise regression analysis showed that WSAs 2–5 mm, SOC in WSAs 0.25–0.5 mm, and TN in WSAs 0.1–0.25 mm were dominant independent variables affecting aggregate stability, and that SOC in WSAs 0.25–0.5 mm and TN in WSAs <0.1 mm were dominant independent variables affecting SOC and TN concentrations in bulk soils, respectively. Long-term application of manure to a solonetz significantly increased macro-aggregates and aggregate stability as well as SOC and TN in bulk soils and all aggregate sizes. These results are likely related to binding agent production as well as C and N accumulation from manure application.

Pasture vegetation near the village of Idjos

A pasture on the solonchakic solonetz soil in the vicinity of the village of Idjos (Banat, Serbia) was found to harbor 137 plant taxa (129 species, 7 subspecies and 1 variety). The plant cover they formed was specific from the ecological, phytogeographical and phytocoenological points of view. The specific ecological feature of the surveyed plant cover was that 47 or 34.31% of the recorded taxa were rated with the ecological index S+ due to their ability to grow in saline soil. The specific phytogeographical feature of the surveyed plant cover was the presence of two Pannonian endemics, Plantago schwarzenbergiana Schur and Statice gmelini subsp. hungaricum (Klokov) So?, and two subendemics, Puccinellia limosa Holmb. and Roripa kerneri Menyh. The specific phytocoenological feature of the surveyed plant cover was the presence of two phytocoenoses from the class Phragmitetea Tx. et Prsg. 1942 (ass. Scirpo-Phragmitetum medioeuropaeum and ass. Bolboschoenetum maritimi continentale), one phytocoenose from the class Molinio- Arrhenatheretea Tx.1937 p.p., Br.-Bl. et Tx. 1943 p.p. (ass. Trifolio-Lolietum perennis) and ten phytocoenoses from the class Festuco-Puccinellietea So? 1968 (ass. Puccinellietum limosae, ass. Pholiuro-Plantaginetum tenuiflorae, ass. Hordeetum histricis, ass. Agrostio-Alopecuretum pratensis, ass. Agrostio-Beckmannietum, ass. Halo-Agropyretum repentis, ass. Poeto-Alopecuretum pratensis halophyticum, ass. Artemisio-Festucetum pseudovinae, ass. Trifolio-Festucetum pseudovinae and ass. Achilleo-Festucetum pseudovinae). The presence of 34.31% of taxa rated with the ecological index S+, the presence of two Pannonian and two sub-Pannonian floristic elements and the predominance of stands from the class Festuco-Puccinellietea So? 1968 led us to conclusion that the pasture near the village of Idjos (Banat, Serbia) is a part of the halobiome of the Pannonian Plain.

Soils with vertic properties in Kamennaya Steppe

The most spread are soils with vertic properties at the territory of Kamennaya Steppe (Voronezh region, Talovsky district) being confined to four landscape positions within 11 different soil combinations derived from clayey or two-layered heavy loam-clayey parent materials. These soils have developed: (A) on bottoms of deep and closed depressions covered by spotted soil combinations in flat watersheds; (B) on some depression bottoms in spotted combinations without solonetzic soils; (C) in different relief elements occupied by chernozemic hydromorphic solonetz complexes and (D) in concave (in long and cross directions) relief elements in the topolithomosaic composition confined to exposed re-deposition products of Dnieper moraine on the slope of Talovaya narrow. Occupying only 0.2% from the total area of agro-forest landscapes, the vertic soils can account for 0.7% to 15% within a separate soil combination and reveal a great diversity. The latter is associated with vertic properties developed together with features of gleying and quasi-gleying, accumulation of calcium carbonates and, on the contrary, clay illuviation against the background of calcium carbonate leaching, solonetz process, salinization, humus formation and the topsoil eluviations. Such a diversity may be adequately reflected both in the soil classification of Russia and in WRB.

Anthropogenic transformation of soil and vegetation resulting from afforestation in southern steppes

Recent data (2006–2008) on characteristics of the vegetation and soils of the solonetzic complex in areas with tree failures within the Volgograd-Elista-Cherkessk forest shelterbelt have been compared with those obtained prior to afforestation (1950). The results show that the vegetation and soils have changed profoundly. Solonetzic agrozems in tree failure sites have been occupied by herbaceous plant communities similar in composition to natural communities. Anthropogenically altered soils formed under forest plantations have no natural analogs. The initial strongly saline shallow (crusty) solonetz soils with a chloride-sulfate or sulfate-chloride composition of salts have transformed into slightly saline solonetzic and solonchakous agrozems with sodium sulfate salinity or with increased alkalinity in the middle of the soil profile and a dealkalized arable horizon.

Characterization of the microbial communities in the modern and buried under kurgans soils of solonetzic complexes in the dry steppes of the Lower Volga region

The microbial communities were studied in the modern and buried under kurgans (1st century AD) soils of solonetzic complexes on the dry steppes of the northern part of the Yergeni Upland. It was found that the changes in the numbers of microorganisms from different trophic groups and in the biomass of the fungal mycelium along the profiles of the modern and buried solonetzic chestnut soils and solonetzes do not differ significantly. The quantitative estimate of the impact of the solonetzic process on the spatial variability of the microbiological parameters of the soils was given on the basis of the ANOVA. As a rule, the values of the microbiological parameters in all the horizons of the modern and buried chestnut soils were 1.2–2.8 times higher than those in the modern and buried solonetzes. The influence of the degree of solonetzicity of the buried paleosols on the microbiological parameters manifested itself in the entire profile, though in each particular horizon it was only seen in the numbers of some particular trophic groups of microorganisms. The comparison between the mean weighted values of the microbiological parameters in the entire soil profiles (the A1 + B1 + B2 horizons) demonstrated an inverse relationship between the population density of the microorganisms utilizing easily available organic matter and the degree of solonetzicity of the buried paleosols. The maximum biomass of the fungal mycelium was found in the solonetzic chestnut paleosol; it exceeded the biomass of the fungal mycelium in the other paleosols (which did not differ significantly in that parameter from one another) by 1.5–1.6 times.