Floodplain soils in the lower reaches of the Khovd River in the Great Lakes Basin of Mongolia

The ecologic-geographic conditions of the pedogenesis and the diversity and classification position of the floodplain soils in the lower reaches of the Khovd River have been studied. The soil cover is composed of alluvial soils of the synlithogenic trunk and solonchaks of the postlithogenic trunk. The major properties of these soils are characterized. The dominant role in the soil genesis is played by gleyzation and salinization processes. Data on the contents of the macro- and microelements in the soils are given, and their agrochemical effect is assessed. Potential destructive agrogenic processes in the soils of floodplain ecosystems upon their use for haymaking and pasturing and upon their use for arable farming are discussed. A grouping of the major soil types in the studied area with respect to their use is proposed.     

Microbial complexes of hydromorphic soils in the Selenga River delta (Baikal region)

The number and the biomass of microorganisms were determined in the soils of the floodplain and islands in the Selenga River delta. The population of fungi in the soils studied was low. The number of saprotrophic prokaryote microorganisms varied from 10⁶–10⁸ CFU/g of soil in the upper horizons to 10⁴–10⁵ CFU/g in the lower horizons of the soils. This pattern is typical for most zonal soils. The microbial biomass in the floodplain soils was 2–4 times as high as that in the soils of the islands. The number of microorganisms of different ecologic-trophic groups participating in the nitrogen and carbon mobilization was much lower than that in the hydromorphic soils of the Transbaikal region or in the cryogenic soils of the Angara River basin (Irkutsk district). The low coefficient of microbiological mineralization and the low coefficient showing the lack of nitrogen (coefficient of oligotrophness) in the soils indicated the weak processes of organic matter decomposition in the soils studied. During the season investigated (August–September), the bacterial complexes in all the soils were dominated by bacteria of the genera Bacillus, Pseudomonas, and Aquaspirillum. In the floodplain soils, streptomycetes constituted a considerable part of the microbial complexes of the floodplain soils, whereas, in the soils of the islands, their number was minor.     

Geobotanical indication of the trophic status and moistening of reclaimed oil-polluted oligotrophic peat soils in the middle reaches of the Ob River

Changes in the trophic status and moistening of oligotrophic peat soils subjected to oil pollution and subsequent reclamation in the middle reaches of the Ob River are discussed. The main plants-indicators are listed. Numerical estimates of the trophic level and the degree of moistening of natural and transformed soils of the widespread bog biogeocenoses—pine-dwarf-shrub-sphagnum, complex ridged-hollow, and cotton grass-sphagnum bogs—are suggested on the basis of the ecological scales developed by L.G. Ramenskii. These estimates have been grouped into several classes used to describe the ecological conditions in natural biogeocenoses of the middle taiga subzone. The main tendencies in the transformation of ecological conditions are revealed. Indicative characteristics of the anthropogenic salinization of peat soils are established.     

Characterizing Uncertainties Associated with Contaminant Transport Modeling through a Coupled Fuzzy-Stochastic Approach

Water, Air, & Soil Pollution - Historic lead mining, milling and smelting on the floodplain soils of the upper reaches of the Vils River, Eastern Bavaria, Germany has led to heavy metal...     

Changes in agrophysical properties of floodplain soils under different anthropogenic loads

Agrophysical properties of alluvial soils were studied in the floodplains of the Oka River and the small rivers of Besputa (the Oka tributary) and Pol’noi Voronezh (the Voronezh tributary). The properties of the soils under different land use types (plowland, hayfield, pasture, and meadow) were compared. The features and degrees of alteration of the properties of the floodplain soils under different uses were determined. The greatest changes in the properties were found for saturated alluvial meadow soils of the Oka River floodplain under plowland. In these areas, strong degradation of the physical status of the soils was noted: compaction of the plow and subplow soil layers, an increase in the content of coarse aggregates and clods, changes in the porespace structure, and a decrease in the soil water permeability. It was shown that the soils of small river floodplains were sensitive to anthropogenic loads. In saturated alluvial soddy soils of the Besputa River floodplain, the soil water permeability decreased because of their compaction under the impact of cattle grazing. Saturated alluvial meadow soils of the Pol’noi Voronezh River floodplain were resistant to anthropogenic loads. Only a tendency towards an increase in the topsoil bulk density was observed under the impact of cattle grazing.     

Soils of floodplains in arid regions of Inner Asia (the Zavkhan River,Mongolia)

The environmental conditions of soil formation and the diversity and classification position of soils developing on the Zavkhan River floodplain are considered, and the morphogenetic and agrochemical properties of these soils are characterized. It is shown that the conditions of soil formation on the floodplain of the Zavkhan River are specified by the mountainous topography, the effect of the large Mongol Els sand massif, the character of the alluviation processes, the groundwater level and salinity, and the regime of floods. The position of the floodplain in the system of altitudinal zones largely dictates the character of the soil cover pattern. In terms of the new Russian soil classification system, the soils studied belong to three trunks, four orders, and seven types: stratified humus alluvial soils, light-humus alluvial soils, light-humus quasigley alluvial soils, light-humus stratozems, and solonchaks. The soils of floodplain ecosystems in arid regions are characterized by low fertility. For their efficient use for pasturing and crop growing, the ecologically balanced differentiated application of manure, mineral fertilizers (NPK), and some microelements is required.     

Phytoindication of the water status and nutrient supply of oil-polluted soils in the middle reaches of the Ob’ River

The method of phytoindication of the soil water status and nutrient supply was applied to natural and oil-contaminated soils in the middle reaches of the Ob’ River. These soil characteristics were indirectly assessed using the ecological scales developed by L. G. Ramenskii. On this basis, changes in the soil water status and nutrient supply under the impact of soil contamination with oil and oil products were estimated for the particular soil and landscape conditions     

Relationship between soil microbial biomass determined by SIR and PLFA analysis in floodplain soils

Purpose  

Although the challenge of linking pedology and hydrology has been identified recently, the microbial diversity in floodplain soils has been studied little in comparison to terrestrial soils. In terrestrial soils, the relationship between soil microbial biomass (SMB) determined by substrate-induced respiration (SIR) and phospholipid fatty acids (PLFA) was examined in several studies. Floodplain soils reveal substantially different properties; they are exposed to drastic changes in water regime from flooded to dry conditions. The relation between SMB determined by SIR and PLFA has, up to the present, not been adequately proved in floodplain soils. Thus, this study was conducted to elucidate the relationship between SMB determined with both methods in a set of floodplain soils of eleven study sites from three study areas along the Elbe River (Germany).     

Holocene evolution of floodplain soils and landscapes in the Kulikovo field area

The lithostratigraphic, radiocarbon, macro- and micromorphological, particle-size, and other analyses have been applied to reconstruct the Holocene evolution of soils and landscapes on the high- and mediumlevel floodplains of the Nepryadva River in the Kulikovo field area. It is shown that the soils buried within the thickness of alluvial sediments on the high- and medium-level floodplains were formed in different times and had their own evolution patterns; the polygenetic nature of these soils is demonstrated. The development of floodplain landscapes in the Holocene was affected by the long-term climatic fluctuations. The bed of the high floodplain was formed during the Late Valdai glacial stage. The beginning of the development of an intricate sequence of buried soils and sediments of the floodplain dates back to the Boreal period. This pedosedimentary sequence in the studied area can be referred to as the Kulikovo sequence. In the course of its formation, the pedogenic stages with a predominant development of soils alternated with the lithogenic stages of active alluviation and deposition of colluvial deposits from adjacent slopes on the floodplain.     

塔里木河中下游湿地及其周边土壤理化性状的空间异质性

研究塔里木河中下游湿地及其周边土壤理化性状,包括土壤粒度组成、土壤水分、盐分、pH和养分的空间异质性结果表明:大范围分布的土壤质地以沙质或粉沙质壤土为主,少数属壤质沙土或粉沙土,不同类型土地或植被条件下土壤粒度组成存在差异;土壤水分的空间分布特征反映了塔里木河中下游湿地的旱化现象;广泛分布的盐土、盐渍化土和碱化土表现出对植物生长发育的明显胁迫作用;土壤有机质、全N和全P总体贫乏,全K含量较高,反映了干旱区湿地土壤的特点。     

Status Quo of Soil Contamination with Inorganic and Organic Pollutants of the River Oka Floodplains (Russia)

The contamination status of rivers and their floodplains with inorganic and organic pollutants in central Russia is poorly known. We investigated the concentrations of inorganic (As, Cd, Cu, Hg, Ni, Pb and Zn) and persistent organic pollutants (hexachlorocyclohexane, PCBs, cyclodienes, DDX and other pesticides) in floodplain soils of the Oka River catchment (Russia). The level of contamination was generally lower than in the Elbe River floodplain but in the same range as in other European river systems such as floodplains of the rivers Rhine, D?evnice and Yachroma. Only soil samples from the periphery of the city of Ryazan (200 km southeast of Moscow) had a higher anthropogenic enrichment of Cd, Cu and Zn which was comparable to the contaminated Elbe River floodplains. These soils also had the largest concentrations of persistent organic pollutants among all samples from the Oka River catchment. Therefore, the need for large-scale remediation seems to be less urgent than in Central European river catchments and mainly restricted to some “hot spot” areas.     

The soil cover of the Selenga delta area in the Baikal region

The main regularities of soil development in the Selenga delta area of the Baikal region have been studied. The terraces of Lake Baikal and the Selenga River are occupied by soddy forest and gray forest soils. Intrazonal saturated and calcareous alluvial soils are formed on the Selenga floodplain and delta. Soddy soils of pine forests occur on natural levees along the streams; hollows and depressions are occupied by swampy soils.     

永定河沙地播草盖沙效果的风洞试验研究

利用野外移动式风洞试验装置,对永定河不同植被覆盖率河滩农地在不同风速下的风蚀量进行了测定,结果表明:播草盖沙可以提高起沙风速,有效减少河滩地的土壤流失。客土地表植被覆盖率达到30%时可比裸露地表减少风蚀量34.55%~58.0%,覆盖率60%时可减少70.48%~84.0%。河滩土植被覆盖率达到30%时即可将风蚀控制在轻微侵蚀范围内。客土有利于植被建设,相同覆盖率和风速下的风蚀量小于河滩土。     

Vertical distribution of <Superscript>137</Superscript>Cs in alluvial soils of the Lokna River floodplain (Tula oblast) long after the Chernobyl accident and its simulation

Profiles of vertical ¹³⁷Cs distribution in alluvial meadow soils on the low and medium levels of the Lokna River floodplain (central part of the Plavsk radioactive spot in Tula oblast) 28 years after the Chernobyl fallout have been studied. A significant increase in the ¹³⁷Cs pool is revealed on the low floodplain areas compared to the soils of interfluves due to the accumulation of alluvium, which hampers the reduction of the total radionuclide pool in alluvial soils because of radioactive decay. The rate of alluvium accumulation in the soil on the medium floodplain level is lower by three times on average. An imitation prognostic model has been developed, which considers the flooding and climatic conditions in the region under study. Numerical experiments have quantitatively confirmed the deciding role of low-mobile forms in the migration of maximum ¹³⁷Cs content along the soil profile in the absence of manifested erosion–accumulation processes.     

Natural and Anthropogenic Changes in the Soils and Environment of the Moskva River Floodplain in the Holocene: Pedogenic,Palynological, and Anthracological Evidences

Several series of well-developed paleosols of different ages have been examined on the Moskva River floodplain. In the beginning of the Holocene, forest-steppe biomes were widespread in this area, and dark-humus (Black) soils with stable humate humus and without features of textural differentiation predominated on the floodplain. The presence of meadow-steppe vegetation communities during this period is confirmed by the results of palynological and anthracological analyses. The lower paleosol in section RANIS 2 is represented by the deep humus horizon with ¹⁴C dates from 5500 to 8400 BP and the carbonate-accumulative horizon; it also contains large and deep tunnels of burrowing animals typical of chernozems. Wood charcoal is absent, and pollen of Artemisia and Chenopodium species predominates. Paleosols of the second half of the Holocene are represented by gray-humus and soddy-podzolic soils (Luvisols). In these soils and in the alluvial sediments, beginning from the Subboreal period, pollen of trees predominates; there are abundant charcoal of spruce and burnt spruce needles. In that time, forest-steppe and broadleaved forest biomes on the floodplain were replaced by southern taiga biomes. The second half of the Holocene is also specified by the human impacts on the local landscapes. Palynological and anthracological data attest to the large-scale burning of forests for pastures in the Bronze Age and, later, for cropland. The paleosol of the Iron Age is enriched in humus. It contains tunnels of burrowing animals related to the stage of anthropogenic meadows. It also contains pyrogenic calcite. The recent centuries have been characterized by extremely high floods triggered by the human activity; they have been accompanied by the fast accumulation of coarse-textured alluvial sediments and the formation of weakly developed alluvial soils.     

Vertical distribution of radiocesium in soils of the area affected by the Fukushima Dai-ichi nuclear power plant accident

Presented are results of the study of radiocesium vertical distribution in the soils of the irrigation pond catchments in the near field 0.25 to 8 km from the Fukushima Dai-ichi NPP, on sections of the Niida River floodplain, and in a forest ecosystem typical of the territory contaminated after the accident. It is shown that the vertical migration of radiocesium in undisturbed forest and grassland soils in the zone affected by the Fukushima accident is faster than it was in the soils of the 30-km zone of the Chernobyl NPP for a similar time interval after the accident. The effective dispersion coefficients in the Fukushima soils are several times higher than those for the Chernobyl soils. This may be associated with higher annual precipitation (by about 2.5 times) in Fukushima as compared to the Chernobyl zone. In the forest soils the radiocesium dispersion is faster as compared to grassland soils, both in the Fukushima and Chernobyl zones. The study and analysis of the vertical distribution of the Fukushima origin radiocesium in the Niida gawa floodplain soils has made it possible to identify areas of contaminated sediment accumulation on the floodplain. The average accumulation rate for sediments at the study locations on the Niida gawa floodplain varied from 0.3 to 3.3 cm/year. Taking into account the sediments accumulation leading to an increase in the radiocesium inventory in alluvial soils is key for predicting redistribution of radioactive contamination after the Fukushima accident on the river catchments, as well as for decision-making on contaminated territories remediation and clean-up. Clean-up of alluvial soils does not seem to be worthwhile because of the following accumulation of contaminated sediments originating from more contaminated areas, including the exclusion zone.     

Morphological diagnostics of pedogenesis on the anthropogenically transformed floodplains in Moscow

At present, many parts of river valleys, including floodplains, are being actively used for urban construction. This leads to the disturbance of normal functioning of the valleys; alluvial deposits and soils become buried under the thickness of various anthropogenic materials. Four profiles of typical urban soils (urbanozems) developed on the floodplain of the Moskva River and its small tributaries have been studied. The macro- and micromorphological characteristics (including data of submicroscopic studies) and the chemical and physicochemical properties of these soils are analyzed. It is shown that the influence of ground-water on the anthropogenically transformed soils of floodplains and low terraces is preserved even upon the cessation of regular flooding. The substitution of urban pedosedimentogenesis for alluvial pedosedimentogenesis has a gradual character with a transitional stage of simultaneous occurrence of both processes. Clayey and clayey-calcareous infillings in the middle-profile horizons and newly formed phosphates of iron and calcium in the lower horizons affected by the groundwater can be considered typical diagnostic features of the urban-alluvial pedogenesis.     

Clay minerals in the stream floodplain soils in undisturbed landscapes of the Southern Taiga (with the soil of the state central forest nature and biosphere reserve as an example)

An X-ray diffraction technique was used to study the composition of clay material from floodplain soddy- and mucky gley soils formed in the valleys of small streams in the reserve. The content of nonexpandable minerals was higher and the labile mineral content was lower in the fine fractions of the floodplain soils than in similar fractions of upland soils found in adjacent positions. Two types of disordered mixed-layered not found in upland soils-namely, illite-chlorites and chlorite-vermiculites with a variable proportion of individual layeres-were detected in the clay material. Both types of mixed-layer minerals are supposed to originate from stony fragments containing phyllosilicates of supergenic or post-magmatic origin.     

Spatial variability of microbial communities in modern and buried soils of the Sakarka River Basin,the Privolzhskaya Upland

A comparative study of the microbial communities of the buried soils under the Anna Ioannovna mound (1718–1720) and the modern soils developed on different geomorphic positions (watershed, slope, and high floodplain) in the Sakarka River basin (the Privolzhskaya Upland) in the dry steppe zone was performed. The varying soil and ecological conditions of the different relief features were established to dictate the differences in the characteristics of the microbial community of the buried and modern soils, in particular, concerning the number of microorganisms belonging to different trophic groups (those restricted to sparse nutrients, humus-consuming ones, and those utilizing easily available organic matter), the ecologo-trophic structure, and the mycelia biomass and structure (the ratio between the light- and dark-colored hyphae). On the basis of the dispersion analysis, a qualitative estimation of the relief features’ impact on the spatial variations of the microbiological parameters of the soils under study is presented.     

不同海拔对干热河谷地区土壤理化性质及可蚀性的影响

以四川省宁南县金沙江下游的河谷地带为研究区域,选择不同海拔下的土壤为研究对象,通过室内测试分析,并运用统计和相关分析等方法,研究不同海拔下的土壤可蚀性变异特征。结果表明,在干热河谷区,海拔对土壤理化性质、机械组成、可蚀性影响显著。在低海拔干热风影响较大的区域,随着海拔的升高,土壤理化性质逐步改善;海拔1 005 m以上地区,干热风影响减弱,土壤理化性质和可蚀性出现转折点,其中理化性质有所降低并趋于稳定,可蚀性显著降低,抗蚀性能显著增强;海拔1 235~1 400 m之间可以作为干热风影响的过渡区,海拔1 500 m以上干热风影响基本消失,植被类型发生变化,土壤可蚀性明显降低,抗蚀性能显著提高。研究结果表明,在金沙江干热河谷区,干热风是影响土壤可蚀性的主要因子之一,因此从水土保持角度出发,在该地区应该尽可能地减少干热风的影响,以提高土地抵抗侵蚀的能力。