Mineralogical composition of the clay fraction and micromorphology of the Middle and Late Pleistocene loesses and paleosols in the center of the East European Plain

The mineralogical composition of the clay fraction and microfabrics of the cryogenic soil-loess sequences of the Middle and Late Pleistocene ages have been studied near the northern boundary of loess sediments on the East European Plain. Poorly ordered mixed-layered mica-smectitic minerals with different portions of smectitic layers predominate in the clay fraction; di-and trioctahedral hydromicas occupy the second place. The clay fraction also contains chlorite, clay-size quartz grains, and feldspars. Individual smectite is present in some of the samples. Interstadial chernozem-like paleosols are specified by the higher content of clay, the maximum concentration of smectitic layers in the mixed-layered minerals, and the presence of individual smectite. The clay fraction in the profiles of interglacial paleosols is sharply differentiated: in the eluvial part, it is depleted of smectite and enriched in kaolinite, hydromica, and clay-size quartz. These features allow us to suppose that interglacial paleosols were subjected to podzolization processes. According to the mineralogical indices, Middle Pleistocene paleosols can be differentiated into those subjected to lessivage (the Kamenskii interglacial paleosol) and podzolization (the Inzhavin interglacial paleosol).     

Trends of the natural evolution of chernozems on the East European Plain

A generalized chronosequence of changes in the morphometric parameters of chernozems in the past 5100 years is analyzed. It is shown that the development of chernozems in the center of the East European Plain is characterized by both long-term (interglacial, encompassing the entire Holocene) and short-term (within separate climatic periods of the Holocene) trends. The long-term trend of the evolution of ordinary chernozems developed from the loess-like calcareous loam consists of a continuous increase in the thickness of the soil humus profile and an oscillating increase in the depth of the carbonate accumulations. The Late-Holocene short-term trends of the natural evolution of chernozems are characterized by the high spatial heterogeneity related to the patterns of climatic fluctuations and to the lithological composition of parent materials. In that period, the thickness of genetic horizons in the forest-steppe chernozems was increasing faster than that in the steppe chernozems.     

Pedosedimentary and climatic reconstruction of the last interglacial and early glacial loess–paleosol sequence in South Tadzhikistan

The thick loess–paleosol-sequences in Tadzhikistan, which indirectly record the environmental changes from the Upper Pliocene to the present-day, have been extensively described from a chronostratigraphical and archaeological point of view. The genesis of the soil-sedimentary complexes and their implications for palaeoenvironmental reconstruction in Tadzhikistan, however, have been considered only relatively recently [Bronger, A., Winter, R., Derevjanko, O., Aldag, S., 1993. Loess–paleosol sequences in Tadjikistan as a palaeoclimatic record of the Quaternary in Central Asia. Quaternary Proceedings 4, 69–81; Lomov, S.P., Tursina, T.V., Zhou, L.P., 1996. Magnetic susceptibility of soils: Micromorphology and possible reconstructions of climate. In: Soil micromorphology. Studies in Soil Diversity, Diagnostics, Dynamics, 10th International Working Meeting on Soil Micromorphology. Moscow, Russia, July 8–13, 1996, p. 145]. The pedocomplex of Last Interglacial and Early Glacial age (Oxygen Isotope Stage 5) in the Tagidjar and Darai Kalon sections near the town of Khovaling is represented by three major stages of soil formation. The soil characteristics have been micromorphologically analysed. The distinction between primary and secondary carbonates is of major importance to understand the soil forming processes. The relative distribution of needle fibre calcite (NFC), micritic infillings (M), hypocoatings (CHC), coarse calcitic grains (CCG) and calcified root cells (CRC) provides detailed insights into the environmental conditions prior, during and following pedogenesis. The abundance of coprolitic aggregates (CA) and pupal chambers gives a clear indication of the rate of biological activity which prevailed during the last two soil forming stages. Void pseudomorphs after gypsum crystals (gypsum pseudomorphs) are frequently observed beneath the Cca horizons of the paleosols. Using the present-day climate and soilscape as a reference base, the obtained pedosedimentary events detected in the Tadzhikistan sections provide a detailed palaeoenvironmental record. Indeed, glacial and interglacial climates and soils respond to contemporaneous climatic schemes and soil forming processes, which are still active in the region today. The amount and the seasonal variability of precipitation, mostly, are at the origin of the variable soils formed during glacial and interglacial ages.     

Soil Indicators of Paleoenvironmental Conditions in the South of the East European Plain in the Quaternary Time

Eurasian Soil Science - Climatic conditions are an important factor affecting mineralogical and chemical compositions of soils and paleosols with the formation of paleosol archives that reflect...     

Surface Runoff and Snowmelt Infiltration into the Soil on Plowlands in the Forest-Steppe and Steppe Zones of the East European Plain

Long-term series of observations over the spring water balance elements on fields with hydrologically contrasting agricultural backgrounds―a loose soil after fall moldboard plowing and a plowland compacted by 12–16% compared to the former soil (perennial grasses, winter crops, stubble)―have been analyzed. The values of surface runoff and water infiltration into the soil in the steppe and forest-steppe zones of European Russia have been calculated for the spring (flooding) period and the entire cold season. The hydrological role of fall plowing has been shown, and water balance elements for the current (1981–2016) and preceding (1957–1980) periods have been compared. A significant decrease in runoff and an increase of water reserve in the soil have been revealed on all plowland types. Consequences of changes in the spring water balance on plowland have been analyzed.     

Biological activity of chernozems in the center of the Russian Plain

Specific features of the microbiological and enzymatic activity of chernozems are considered in genetically associated and technogenic series. The biological processes in chernozems follow the main soil-geographical regularities inherent to the Central Chernozemic region. The biological characteristics of the chernozems reflect the dynamic properties of the microorganisms habitat and are indicators of their technogenic degradation. Plowing of chernozems and their intense agricultural use is accompanied by changes in their biological activity. The disturbances revealed in the biosystem of the chernozems caused by plowing and fertilization were of a functional, i.e., reversible character. The changes in the intensity of the biochemical processes in the chernozems were observed only under the long-term application of fertilizers (for not less than 10 years). A single application of fertilizers caused temporary changes.     

Specificity of actinomycetal complexes in urbanozems of the city of Kirov

The number and composition of the actinomycetal population was studied in urbanozems in the city of Kirov. It was shown that the total population of actinomycetes was an order of magnitude lower than that in the background territories, and the generic structure of the actinomycetal complex and the species composition of the streptomycetes were transformed under the influence of the urbanization factors. The obtained data were compared with the concentrations of the mobile forms of Pb, Zn, Cu, Fe, and Mn in different ecotopes (industrial, traffic, and recreation zones). The increase of the relative portion of micromonosporic actinomycetes in comparison with the background (reference) soils was observed in the complexes of the industrial and transport ecotopes mostly contaminated with heavy metals. It was found that the antibiotic potential of the streptomycetes in the contaminated soils was lower than in the soils of the background territories.     

Quantitative Estimates of Paleoenvironmental Changes in the Late Holocene in the South of the East European Plain as Recorded in the Magnetic Properties of Soils

Eurasian Soil Science - Information about the past evolutionary changes in the soil cover is essential as a retrospective basis for long-term forecasts of soil development under the changing...     

Comparative micromorphology of two late Pleistocene paleosols (in the Paris Basin)

The micromorphology of two late Pleistocene paleosols in the Paris Basin, St. Pierre-les-Elbeuf and Bois du Moulin were studied in order to characterize their pedogenicand sedimentary processes and to reconstruct and interpret the pedosedimentary history and climate of each profile. The micromorphological observations of greatest interpretive value were the types of clayey and silty textural accumulations (argillans and siltans), pedality and porosity; of lesser value were papules, bioactivity and concretions.During the last interglacial period on both profiles developed a sol brun lessivé, comparable to those developed during the Holocene. With the onset of cold conditions of the last Glaciation, the two differentiate pedologically and sedimentologically. At Elbeuf, in the Seine Valley, we observe colluviation of silts and the development of grey forest soils with strong textural degradation under cold and moderately dry local conditions. At Moulin, on the plateau the grey forest phase is very weak and probably brief and is followed by a marked phase of churning and eluviation of silt; conditions were wetter than in the valley, such that the upland position protected the profile from colluvial truncation.The advantages of micromorphology in interpreting pedo-sedimentary sequences is discussed.     

Mycological complexes in Holocene and Late Pleistocene paleohorizons and in fragments of paleosols

Fragments of buried Late Pleistocene (30000-year-old) and Early Holocene (10000-year-old) paleosols contained viable complexes of microscopic fungi. The mycobiota of these paleosols represents a pool of fungal spores that is lower in number and species diversity as compared to that in the recent humus horizons and higher than that in the inclosing layers. The central part of the paleosol profiles is greatly enriched in microscopic fungi. In the intact humus horizons of the Late Holocene (1000–1200 years) paleosols, actively functioning fungal complexes are present. These horizons are characterized by their higher level of CO₂ emission. The buried horizons, as compared to the recent mineral ones, contain a greater fungal biomass (by several times) and have a higher species diversity of microscopic fungi (including fungi that are not isolated from the recent horizons). Nonsporulating forms are also present there as sterile mycelium. The seasonal dynamics of the species composition and biomass of the fungal complexes were more prominent and differed from those inherent to the surface soil horizons. In the buried humus horizons, the dynamics of the fungal biomass were mainly due to the changes in the content of spores. The data on the composition of the fungal complexes in the buried soils confirm (due to the presence of stenotopic species) the results of paleobotanic analyses of the past phytocenoses or do not contradict them.     

Systematization of Organo-Clay combinations in soils of the center of the Russian Plain

A systematization of organo-clay combinations in zonal soils of the center of the Russian Plain is suggested. This systematization adequately reflects the zonal features of pedogenesis and agrees with traditional estimates of the ecological state of the soils and their tolerance toward the agrogenic degradation. The four types of organo-clay combinations are characterized by different degrees of humification, aggregation, tolerance toward soil compaction, and tolerance toward soil degradation.     

黄土高原与俄罗斯平原南部干旱地区人工林营造策略分析

通过对比中国黄土高原地区与俄罗斯欧洲部分东南部地区森林生长状况,分析了人工林系统的异同点,探索了可持续的人工造林策略.认为必须通过重新分配大气降水而补充林下土壤水分来改善人工林的生长状况和缓解土壤干化,在中国黄土高原地区可通过调节暴雨径流来实现,而在俄罗斯可通过集中降雪和调节融雪径流实现.     

Reconstruction of the paleotemperature and precipitation in the Pleistocene according to the isotope composition of humus and carbonates in loess on the Russian Plain

The isotope composition of carbon and oxygen in humus and carbonates has been studied in the Pleistocene loess and soil of the Russian Plain in order to reconstruct the paleoclimatic parameters during the time of their formation. It is established that most of the buried soils were formed upon the mean annual temperature exceeding the modern temperature by 1–2°C. The climate aridity (the portion of C4 plants in the ecosystem) varied from 0 to 25%. It is shown that the isotope composition of carbon and oxygen in the humus and carbonates may be a reliable indicator of the paleoclimate (i.e., the paleotemperature, paleoprecipitation, and aridity dynamics). An isotope procedure of culling soil samples unsuitable for paleoclimatic reconstruction is proposed.     

Micromycetes in podzolic and bog-podzolic soils in the middle taiga subzone of northeastern European Russia

The qualitative and quantitative characteristics of the mycobiota in podzolic and bog-podzolic soils were studied in the middle taiga subzone (the Republic of Komi). The complex of micromycetes was found to include 73 species of 18 genera from the Zygomycota and Ascomycota orders and from the formal class of anamorphic fungi. The latter has the following specific features: many forms of sterile mycelium, the predominance of Penicillium species (25), the constant presence of Mucor and Trichoderma species, and single Aspergillus species. With increasing moisture in the sequence of the podzolic, surface-gleyic podzolic, peaty podzolic-gleyic, and peat podzolic-gley soils, the dominant soil fungi are preserved, but the species composition of the micromycete complexes becomes poorer due to the removal of rare species. In the podzolic and bog-podzolic soils, fungi absolutely predominate in the microbial biomass. They accounted for more than 99% of the total biomass, 1–6% of the latter is the biomass of spores, and more than 94% falls on mycelium. In these soils, the reserves of bacterial biomass, as compared to those of fungi, are lower by two orders of magnitude.     

黄淮冬麦区早、晚熟冬小麦品种生长发育特性的研究

对黄淮海冬麦区早熟小麦品种 (系 )“890 1 11 14”和日本国引种晚熟品种“黑小麦 1号”[TriticumaestivumL .(HeixiaomaiNo .1]与当地普通小麦品种“4 185”大田试验比较结果表明 ,晚熟品种“黑小麦 1号”不适宜在黄淮海平原(河北省藁城试区 )麦玉两熟套作种植 ,早熟小麦品种 (系 )“890 1 11 14”播期、生育期和收获期与普通小麦品种“4 185”基本相似 ,且其分蘖特性强、灌浆强度集中和株高适中 ,在该地种植有良好生态适应性 ;根据不同冬小麦品种分蘖特性大田栽培时应采取适宜对应措施 ,冬小麦品种“890 1 11 14”应适当降低其种植密度 ,并采用合理促控措施以提高其分蘖成穗率。     

末次间冰期以来临夏地区气候变化的黏土矿物学及地球化学记录

临夏盆地塔湾剖面黄土-古土壤沉积物的黏土矿物学及常量元素特征分析表明,末次间冰期以来临夏地区气候变化经历了从相对温暖湿润(Ⅰ阶段:92.4～78.8 ka)—寒冷干燥(Ⅱ阶段:78.8～59.8ka)—相对温暖湿润(Ⅲ阶段:59.8～47.7 ka)—寒冷干燥(Ⅳ阶段:47.7 ka以来)等4个阶段的演化。黄土-古土壤中黏土矿物以伊利石、绿泥石、伊/蒙混层及坡缕石等为主,并且坡缕石在沉积物中广泛发育,表明末次间冰期以来临夏地区总体上以相对干燥为主。w(TiO2)/w(Al2O3)比值表明沉积物剖面中黄土-古土壤层可能具有相同的物源,黄土-古土壤交替的发育特征应该为不同时期风化程度差别所致,与当时的大气降水量及温度密切相关。在相对温暖湿润的时期,黏土矿物相对含量、化学蚀变指数CIA值及w(Al2O3)/w(Fe2O3)、w(SiO2)/w(Al2O3)、w(SiO2)/w(Fe2O3)和w(MgO)/w(Al2O3)等氧化物比率变化波动较大;在寒冷干燥的时期,黏土矿物相对含量、CIA值及各氧化物比率较为稳定。黏土矿物学及常量元素变化特征共同揭示92.4～78.8 ka期间和47.7 ka以来出现明显的降温事件,说明临夏地区末次间冰期以来气候环境的不稳定性,可能与高原冬、夏季风的此消彼长密切相关。     

Upper Permian paleosols of the East European Platform: Diagnostics of pedogenesis and paleogeographic reconstruction

A vertical sequence of seven buried paleosols composing the Klimovsk pedocomplex was studied in the basin of the Sukhona River (Vologda oblast). These paleosols were formed according to the accumulative model of pedogenesis (pedosedimentation model). They had monogenetic profiles with eluvial-gley, structural, and carbonate-illuvial types of differentiation. The set of elementary pedogenic processes responsible for the development of these soils included gleyzation in the surface horizon and around the roots, the inter- and intrahorizon translocation and segregation of iron, structuring, humification, weathering, lessivage, the migration and segregation of carbonates, and the synthesis of palygorskite and analcime. The studied paleosol profiles make it possible to reconstruct seven pedogenetic stages; each of them lasted for about n × 10²–10³ years. The paleosols were formed on a flat lacustrine-alluvial plain with drying lakes and temporary streams. The stages of inundation and water stagnation on the surface alternated with the stages of drying of the territory. The climate was warm, with well-pronounced wet and dry seasons. Against this general climatic background, arid climatic epochs marked by the development of calcic paleosols alternated with humid climatic epochs marked by the development of noncalcareous paleosols.     

Genesis of the silty sands and loams within the periglacial zone in the center of the Russian Plain and the properties of soils developed from them

The genesis and spatial differentiation of the silty sands and loams deposited during the Late Valdai glaciation have been studied in the central part of the Russian Plain within the Mologa-Sheksna Lowland and on terraced slopes of the Ovinishchensk Upland (Yaroslavl oblast). The stratigraphy of these sediments on different elements of the local topography and data on their particle-size distribution suggest that they belong to the same paragenetic group. Some differences in the particle-size distribution can be explained by the specificity of sedimentation in periglacial lakes found at different geomorphic levels (from 102 to 180 m a.s.l.) during the Ostashkov phase of the Valdai glaciation. For the first time, statistically significant differences in the properties of Holocene soils developed at different hypsometric levels have been revealed. The degree of textural differentiation of the soils developed from silty loams increases with an increase in the absolute height of the surface. The analysis of factual materials makes it possible to suggest that a system of impounded lakes existed in this area during the Ostashkov (maximum) phase of the Valdai cryochron; the water level in these lakes reached a maximum height of 180 m a.s.l.     

湖北省早、中、晚稻施磷增产效应及磷肥利用率研究

2006～2009年通过在湖北省18个县(市、区)布置多点田间肥效试验,研究了当前生产条件下施用磷肥对水稻产量的影响,明确了磷肥的利用率现状,并探讨了早、中、晚稻施磷效果的差异。结果表明,当前生产条件下,早、中、晚稻施用磷肥都有显著的增产效果,平均增产量分别为706、774和565 kg/hm2,增产率分别为13.3%、11.3%和9.4%。不同类型水稻对磷肥投入的反应不同,相应的磷肥利用率也不同,早、中、晚稻的磷肥（P2O5）农学利用率平均分别为13.3、13.3和11.6 kg/kg,偏生产力分别为116.4、148.0和157.5 kg/kg,吸收利用率分别为14.2%、13.7%和11.3%,生理利用率分别为85.2、110.4和65.4 kg/kg。3种类型水稻对土壤磷素的依存率平均在87%～89%之间,说明水稻吸收的磷主要来自于土壤而不是肥料,其中晚稻对土壤磷素的依赖程度相对最大。