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The contents of 90 Sr and 137 Cs and the pattern of their redistribution in the soil and plant cover of floodplain ecosystems have been assessed. It is shown that the radionuclide distribution across the floodplain and along the river flow is determined by the formation of a barrier to their migration near the river channel, at which less mobile 137 Cs accumulates. The soil and plant cover of the central floodplain are enriched with 90 Sr. Differences in radionuclide migration in floodplain soils and their input into plants are determined by the rela- tionship between the processes of their immobilization and migration with soil water.

Pseudomaryna australiensis and Colpoda brasiliensis were discovered in floodplain soils from Australia and Brazil and studied in vivo and in silver preparations. They have a common feature, viz., a sheath of clay (mineral) particles embedded in a slimy matrix. Such sheaths, which evolved convergently in various ciliates, are termed “mineral envelopes” and make cells appear like inorganic soil particles, possibly protecting them from predators. The new genus Pseudomaryna belongs to the family Colpodidae and is characterized by the preoral suture which extends for the whole body length right of the oral opening due to the widely projecting left side ciliary rows. Maryna antarctica Foissner, 1993 has the same ciliary pattern and is thus transferred to the new genus: Pseudomaryna antarctica (Foissner, 1993) nov. comb. Both, P. australiensis and P. antarctica are small (length 25–60 μm), reniform soil ciliates differing in the macronuclear structure (with vs. without central nucleolus), the mineral envelope (present vs. absent), and details of the somatic and oral ciliary pattern. Colpoda brasiliensis is also a small ciliate (about 33 × 18 μm), differing from the congeners by the mineral envelope and a combination of ordinary features, viz., the location and structure of the macronucleus and the preoral ciliary pattern. Probably, it is related to the Colpoda steinii group.

Soil sediment samples of 10 layers with a spacing of 10 cm each were collected in different floodplain zones adjacent to Huolin River in the Xianghai Nature Reserve, and contents of total N, total P and organic matters were analyzed. The results showed that contents of total N, total P and organic matters were generally decreasing with the increase of distance from sample locations to the river channel, and contents of the three items were generally higher in the upper soil layer than that in the lower soil layer. The content variations displayed how flooding functions influenced nutrient matter content variations in floodplain soils since the flood inundation frequencies of the sample locations varied. The correlation analysis displayed that there were remarkable relativities between total N, total P and organic matters within definite spatial distance from the Huolin River channel.

Measuring soil organic carbon (SOC) in riparian forest soils affected by floods is crucial for evaluating their concentration and distribution along hydrological gradients (longitudinal and transversal). Hydromorphological factors (e.g., sedimentation vs. erosion, size of floodplain, flood recurrence) may be the cause of major variations in the concentration of organic matter and SOC in soils and could have a direct impact on C levels in soil profiles. For this study, SOC concentrations were assessed in riparian soils collected along transects perpendicular to the riverbanks which cross through inundated and non-inundated zones. Other soil properties (e.g., acidity, nitrogen, texture, bulk density) that may affect the concentration of SOC were also considered. The main purpose of this study was to assess SOC concentrations in soils subjected to flooding with those outside the flood zones, and also measure various soil properties (in surface soils and at various depths ranging from 0 to 100 cm) for each selected area. Across the various areas, SOC shows marked differences in concentration and spatial distribution, with the lowest values found in mineral soils affected by successive floods (recurrence of 0–20 years). SOC at 0–20 cm in depth was significantly lower in active floodplains (Tukey HSD test), with average values of 2.29 ± 1.64% compared to non-inundated soils (3.83 ± 2.22%). The proportion of C stocks calculated in soils (inundated vs. non-inundated zones) was significantly different, with average values of 38.22 ± 10.40 and 79.75 ± 29.47 t·ha−1, respectively. Flood frequency appears to be a key factor in understanding the low SOC concentrations in floodplain soils subjected to high flood recurrence (0–20 years).

In floodplain soils, As may be released during flooding-induced soil anoxia, with the degree of mobilization being affected by microbial redox processes such as the reduction of As(V), Fe(III), and SO4(2-). Microbial SO4(2-) reduction may affect both Fe and As cycling, but the processes involved and their ultimate consequences on As mobility are not well understood. Here, we examine the effect of microbial SO4(2) reduction on solution dynamics and solid-phase speciation of As during flooding of an As-contaminated soil. In the absence of significant levels of microbial SO4(2-) reduction, flooding caused increased Fe(II) and As(III) concentrations over a 10 week period, which is consistent with microbial Fe(III)- and As(V)-reduction. Microbial SO4(2-) reduction leads to lower concentrations of porewater Fe(II) as a result of FeS formation. Scanning electron microscopy with energy dispersive X-ray fluorescence spectroscopy revealed that the newly formed FeS sequestered substantial amounts of As. Bulk and microfocused As K-edge X-ray absorption near-edge structure spectroscopy confirmed that As(V) was reduced to As(III) and showed that in the presence of FeS, solid-phase As was retained partly via the formation of an As2S3-like species. High resolution transmission electron microscopy suggested that this was due to As retention as an As2S3-like complex associated with mackinawite (tetragonal FeS) rather than as a discrete As2S3 phase. This study shows that mackinawite formation in contaminated floodplain soil can help mitigate the extent of arsenic mobilization during prolonged flooding.

This document is the final technical report for a project designed to address fundamental processes controlling the release of mercury from flood plain soils associated with East Fork Poplar Creek, Tennessee near the U.S. Department of Energy Oak Ridge facility. The report summarizes the activities, findings, presentations, and publications resulting from an award to the U.S. Geological that were part of a larger overall effort including Kathy Nagy (University of Illinois, Chicago, Ill) and Joseph Ryan (University of Colorado, Boulder, CO). The specific charge for the U.S.G.S. portion of the study was to provide analytical support for the larger group effort (Nagy and Ryan), especially with regard to analyses of Hg and dissolved organic matter, and to provide information about the release of mercury from the floodplain soils.

It is demonstrated in model experiments that in the presence of Ca ions (typomorphous cations of water of the Yenisei River) fulvic acids of floodplain soils and associated radionuclides (Am, Eu) form poorly soluble mixed Ca, Fe, Al(Am, Eu) fulvates. As a result, under the flooding conditions the migration of Am and Eu in the form of solubilized organomineral complexes is practically totally suppressed. With decreasing pH in the model system from 8 to 6 the mobility of the radionuclides noticeably increases.

study area was assessed with respect to its heavy-metal load on the basis of the current guideline values. The heavy-metal loads of the soils in the study area have ranges of

A novel mercury-specific sequential extraction procedure (SEP) for the assessment of mercury (Hg) speciation in soils and sediments, with emphasis on studying the interaction between Hg and organic matter (OM), was developed and tested. It was applied to determine Hg speciation in floodplain topsoils and surface sediments along the Hg-contaminated part of the river Elbe, and to simultaneously derive some information on the (re)mobilization potentials for Hg from these matrices. The majority of the total Hg in the ecosystem today is bound in the floodplains, which also still geographically reflect the historic emission record. Most of the Hg in both matrices is bound strongly to OM, suggesting low availability. However, distinct differences between Hg speciation in the floodplain soils and sediments were also discovered. Mercury deposited in the floodplains shows speciation patterns that indicate stronger fixation compared with Hg in the sediments. This difference is attributed to the association of Hg with larger quantities of OM, which presumably also has higher molecular weight (MW). By comparison, Hg in the sediments was distributed among weaker binding forms, which are more likely to liberate Hg. Particularly, sediments showed a total lack of sulfidic binding forms for Hg. Pronounced geographical trends were detected in the Hg speciation along the river transect, with a general downstream shift from weaker to stronger binding forms, probably due to increased association with OM. These studies indicate that Hg speciation in riverine ecosystems is dynamic and reflects the chemical mechanisms underlying (bio)geochemical processes like distribution and transport.

International audience; Flood pulses are major drivers of river-floodplain processes. We investigated their effects on soil nitrogen (N) transformations along a lateral gradient from the river to a mature alluvial forest in the Thur River floodplain (NE Switzerland). Selected N pools (ammonium and nitrate) and N transformations (mineralization, nitrification and denitrification) in the topsoils were repeatedly quantified over a period of six months. During this period, the floodplain was affected by two flood events of different magnitude. Our results showed a distinct difference in size and temporal changes of N pools and transformation rates among functional process zones (FPZs) differing in flooding disturbance. A strong temporary increase in N mineralization in a FPZ with young soil on the frequently flooded gravel bars was the most prominent flood-related effect. This was most likely related to the fast-flowing water during inundation that deposited fresh dispersed sediments with a coarse sandy texture containing highly bioavailable organic N, and/or stimulated the turnover of existing N by destroying sediment aggregates already present before the flood. Increased N mineralization appeared to stimulate coupled nitrification-denitrification in this FPZ during the drying phase. In the more stable FPZs, N mineralization was not strongly enhanced by flooding, whereas nitrification and denitrification were also increased during the drying phase, however to a lesser degree than in the gravel bar soils. Based on our results we propose that floodplain zones characterized by short intensive floods with fast over-flowing water are "hot spots" and the drying phases after the floods are "hot moments" of N transformations.

The study deals with the combined contribution of polycyclic aromatic hydrocarbons (PAHs) and metals to health risk in Delhi soils. Surface soils (0–5 cm) collected from three different land-use regions (industrial, flood-plain and a reference site) in Delhi, India over a period of 1 year were characterized with respect to 16 US Environmental Protection Agency priority PAHs and five trace metals (Zn, Fe, Ni, Cr and Cd). Mean annual ∑16PAH concentrations at the industrial and flood-plain sites (10,893.2 ± 2826.4 and 3075.4 ± 948.7 μg/kg, respectively) were ~15 and ~4 times, respectively, higher than reference levels. Significant spatial and seasonal variations were observed for PAHs. Toxicity potentials of industrial and flood-plain soils were ~88 and ~8 times higher than reference levels. Trace metal concentrations in soils also showed marked dependencies on nearness to sources and seasonal effects. Correlation analysis, PAH diagnostic ratios and principal component analysis (PCA) led to the identification of sources such as coal and wood combustion, vehicular and industrial emissions, and atmospheric transport. Metal enrichment in soil and the degree of soil contamination were investigated using enrichment factors and index of geoaccumulation, respectively. Health risk assessment (incremental lifetime cancer risk and hazard index) showed that floodplain soils have potential high risk due to PAHs while industrial soils have potential risks due to both PAHs and Cr.

Environmental pollution by mercury is a world-wide problem. Particularly floodplain ecosystems are frequently affected. One example is the Elbe River in Germany and its catchment areas; large amounts of Hg from a range of anthropogenic and geogenic sources have been accumulated in the soils of these floodplains. They serve as sink for Hg originating from the surface water of adjacent river. Today, the vastly elevated Hg contents of the floodplain soils at the Elbe River often exceed even the action values of the German Soil Conservation Law. This is especially important as Hg polluted areas at the Elbe River achieve several hundred square kilometres. Thus, authorities are coerced by law to conduct an appropriate risk assessment and to implement practical actions to eliminate or reduce environmental problems. A reliable risk assessment particularly with view to organisms (vegetation as green fodder and hay production, grazing and wild animals) to avoid the transfer of Hg into the human food chain, requires an authentic determination of Hg fluxes and their dynamics since gaseous emissions from soil to atmosphere are an important pathway of Hg. However, reliable estimates of Hg fluxes from the highly polluted floodplain soils at the Elbe River and its tributaries, and its influencing factors are scarce. For this purpose, we have developed a new method to determine mercury emissions from soils at various sites. Our objectives were i) to quantify seasonal variations of total gaseous mercury (TGM) fluxes for floodplain soils at the Elbe River, ii) to provide insights into physico-chemical processes regulating these TGM fluxes, and iii) to quantify the impacts of the controlling factors soil temperature and soil water content on Hg volatilization from a typical contaminated floodplain soil within soil microcosm experiments under various controlled temperature and moisture conditions. Our study provides insight into TGM emissions from highly Hg-polluted floodplain soils in Germany and that those emissions are an underestimated problem. Current needs for reliable risk assessments, the induced implications for authorities, and future challenges will be discussed. The presented data will contribute to a better understanding of seasonal dynamics of Hg fluxes and its controlling factors. This presentation should be of large interest for a wide international audience, such as environmental scientists and managers, applied ecologists, and authorities.

Concentrations of polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo-p-dioxins (PCDDs) in Tittabawassee River floodplain soils and biota downstream of Midland, Michigan, USA, are greater than regional background concentrations. From 2005 to 2008, a multiple lines of evidence approach was utilized to evaluate the potential for effects of PCDD/DFs on American robins (Turdus migratorius) breeding in the floodplains. A dietary-based assessment indicated there was potential for adverse effects for American robins predicted to have the greatest exposures. Conversely, a tissue-based risk assessment based on site-specific PCDD/DF concentrations in American robin eggs indicated minimal potential for adverse effects. An assessment based on reproductive endpoints indicated that measures of hatch success in study areas were significantly less than those of reference areas. However, there was no dose-response relationship between that endpoint and concentrations of PCDD/DF. Although dietary-based exposure and reproductive endpoint assessments predicted potential for adverse effects to resident American robins, the tissue-based assessment indicates minimal to no potential for adverse effects, which is reinforced by the fact the response was not dose related. It is likely that the dietary assessment is overly conservative given the inherent uncertainties of estimating dietary exposure relative to direct tissue-based assessment measures. Based on the available data, it can be concluded that exposure to PCDD/DFs in the Tittabawassee River floodplain would not likely result in adverse population-level effects to American robins. Environ Toxicol Chem 2013;32:1304–1316. © 2013 SETAC

Vanadium (V) is a naturally occurring trace element, but total concentrations in soils and sediments are also dependent on the parent material and might be influenced by anthropogenic activities (e.g., steel industry). Despite the fact that threshold values for V in soils and/or sediments exist in various European countries, in Belgium, V is not taken into account when the environmental quality of soils and sediments has to be evaluated, despite the existence of several (diffuse) sources for V. In the first part of the study, the occurrence of V alluvial soils in Belgium was compared with V concentrations in alluvial soils (floodplain soils) across Europe. By analysis of both the Belgian and European data, the relationship between physicochemical soil characteristics and total V concentrations was quantified and some areas polluted with V were detected. A regression equation, in which V concentrations in alluvial soils were expressed as a function of major element composition, was proposed for the Belgian and European data. Additionally, single extractions with CaCl2(0.01 mol L-1) and ammonium-EDTA (0.05 mol L-1) were used to estimate short- and long-term mobility of V in the alluvial soils.

Several fractions of technogenic radionuclides were separated from floodplain soil by sequential extraction, among them radiocolloids of 60Co and Eu nuclides associated with components of polymeric organomineral films [Fe(III) and Al(III) oxides and hydroxides] and organomineral complexes of 60Co, 137Cs, and Eu nuclides with humic compounds. Changing the oxidizing agent, H2O2, for chromic acid in the sequential extraction procedure allowed a considerable increase in the yield of the radionuclides to the solution: from 6.5 to 46% for 60Co, from 1.4 to 36% for 137Cs, and from 5.2-8.5 to 23-32% for the Eu isotopes.

Submitted by (lucia.rodrigues@ufrpe.br) on 2016-08-16T14:23:12Z No. of bitstreams: 1 Suzana Kelley Gomes de Mendonca.pdf: 1457356 bytes, checksum: 55d06ce86944cd3f69644577e424587d (MD5) Made available in DSpace on 2016-08-16T14:23:13Z (GMT). No. of bitstreams: 1 Suzana Kelley Gomes de Mendonca.pdf: 1457356 bytes, checksum: 55d06ce86944cd3f69644577e424587d (MD5) Previous issue date: 2011-02-25 Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq Low lands in Brazil have a great potential for agriculture, however, they have some limitations due to the presence of high water table and severe risk of flooding. When located near by the sea cost, these floodplains can have influence of the sea water, resulting in the presence of sulfide soils, which, if drained, can develop sulfuric horizons. The sulfuric horizons are mainly characterized by high levels of acidity and exchangeable aluminum, which can result in serious environmental impact to the ecosystem. The agriculture use of these soils requires a deep knowledge of soil physical, chemical and mineralogical properties, in order to support the development of sustainable management practices. The objective of this work was to study chemical and mineralogical properties of acid sulfate soils formed in the floodplain of Camocim river, Caaporã municipality, state of Paraíba. The main aim was to support decisions on the viability of sugarcane cropping in these areas. Soils were characterized morphologically and samples were collected along a transect from the high land towards the river channel. Besides the routine physical, chemical and mineralogical analysis, other determinations were carried out involving total sulfur, incubation pH, soluble anions, electrical conductivity of the saturation extract and sequential iron extraction. The soils were classified as: Argisolic,Dystric Tb Haplic Gleysol (P1) Typic Sapric Sulfide Organosol (P2), Organosolic Orthic Sulfide Gleysol (P3 and P4). Soil distribution in the landscape of the Camocim river floodplain is mainly related to the relief, which determines drainage, water table and, consequently, the soil forming processes related to water excess. The presence of sulfuric horizons occur at the surface, in the very poorly drained soil profiles, and at 43 cm depth in the poorly drained soils close to the river channel. The studied acid sulfate soils do not have salinity at present time, and the high electrical conductivity is determined by the formation sulfuric acid (H+ + SO4 2-) from pyrite oxidation. Sugarcane crop decay in the floodplain of Camocim River, after one year of cultivation was a consequente of the sulfuric horizon formation after the implementation of the drainage system in soils with sulfide materials. The main soil minerals, indentified by X-ray diffraction, in the clay fraction were jarosite quartz, feldspars, kaolinite, smectite (essentially montmorillonite), illite and gibbsite. Quartz and feldspars were the minerals identified in sand and silt fractions. The results of the iron sequential extraction showed predominance of non crystalline iron oxides and very low amounts or absence of iron associated with pyrite, reflecting the advanced oxidation stage determined by the drainage system. As áreas de várzeas no Brasil apresentam um grande potencial para a agricultura, no entanto, estas áreas apresentam algumas limitações ao uso agrícola devido à presença de lençol freático elevado e risco freqüente de inundação. Quando localizadas em áreas litorâneas, estas áreas podem sofrer influência marinha podendo apresentar solos tiomórficos que, quando drenados, formam horizonte sulfúrico, caracterizados principalmente pela elevada acidez, elevados teores de alumínio trocável, podendo causar sérios impactos ambientais no ecossistema onde ocorrem. A incorporação destas áreas no processo produtivo depende de um profundo conhecimento das propriedades físicas, mineralógicas e principalmente químicas, de forma a subsidiar o desenvolvimento de técnicas sustentáveis de manejo. Neste contexto, foi realizada a caracterização física, química, mineralógica, além da extração sequencial de ferro de solos tiomórficos desenvolvidos na várzea do rio Camocim, no município de Caaporã, PB. O objetivo do estudo foi identificar a ocorrência de solos tiomórficos e caracterizá-los, com o fim de obter subsídios para a tomada de decisão de incorporar estas áreas ao cultivo de cana-de-açúcar ou mantê-las nas condições naturais. Para tanto foi feito um transecto perpendicular ao canal principal do rio, a partir das terras altas, onde foram descritos e coletados quatro perfis de solo. Em campo foi realizada a caracterização morfológica dos perfis e coletadas amostras para as análises físicas, químicas e mineralógicas de rotina, além de análises específicas para determinação do enxofre total, pH de incubação, ânions solúveis, CE do extrato da pasta saturada e extração sequencial de ferro. Os solos foram classificados como Gleissolo Háplico Tb Distrófico argissólico (P1), Organossolo Tiomórfico Sáprico típico (P2) e Gleissolo Tiomórfico Órtico organossólico (P3 e P4). A distribuição dos solos na várzea do rio Camocim guarda estreita relação com o relevo, que condiciona a drenagem e, consequentemente, os processos de formação relacionados com o excesso de água. A presença de horizonte sulfúrico foi constatada a partir do horizonte superficial nos perfis muito mal drenados da planície de inundação, e a partir de 43 cm, nos solos mal drenados da ombreira. Os solos tiomórficos estudados não apresentam salinidade, sendo a alta condutividade elétrica resultante da formação de ácido sulfúrico proveniente da oxidação da pirita (H+ e SO4 2-). A degradação do canavial em grandes áreas da várzea do rio Camocim, após um ano de cultivo, foi consequência da formação do horizonte sulfúrico com a drenagem da área, tendo em vista que os materiais sulfídricos ocorrem desde a superfície. Os minerais identificados por DRX foram: jarosita, quartzo, feldspatos, caulinita, esmectita (essencialmente montmorilonita), ilita e gibbsita, na fração argila. Quartzo e feldspatos foram os minerais identificados nas frações areia e silte. Os valores da extração sequencial de ferro mostraram predomínio de formas não cristalinas de óxidos de ferro e baixíssimos teores ou ausência de ferro associado à pirita, indicando que os solos tiomórficos estudados apresentam avançado estágio de oxidação, promovido pela drenagem realizada na área de estudo na tentativa de viabilizar o cultivo da cana-de-açúcar.

This paper reviews the role of earthworms in the early colonisation of contaminated soils as well as sediment and waste deposits, which are worm-free because of anthropogenic activities such as open-cast mining, soil sterilisation, consistent pollution or remediation of contaminated soil. Earthworms live in close interaction with their soil environment and are able to change it considerably by their burrowing and litter comminuting behaviour. While earthworms have been studied extensively, several questions still remain unanswered such as: What are the characteristics of successful early colonisers? Do they function well in dispersal, individual establishment or population growth? Do the negative environmental conditions in these kinds of anthropogenic soils hamper colonization or are these colonizers relatively resistant to it? To what extent does colonization change the characteristics of the colonized substrate? In short, do earthworms impact the soil? In this paper, the characteristics that make earthworms successful colonisers are briefly described as well as which species are the most successful and under what circumstances, and what do earthworms contribute to the total process of succession. We propose that it is not so much eco-type or r-K strategy that govern success and succession of earthworm colonisation but rather environmental flexibility not only towards pH, desiccation, and temperature but also towards contaminants such as heavy metals. Moreover, the formation of an organic litter layer, in close connection with re-vegetation of the area, is essential for establishing earthworm populations, which, at first, are mainly superficially and shallow active species. The burrowing and organic matter digesting activity of these earthworms changes the upper soil to a well mixed humus layer suitable for deep burrowing earthworm species.

Aerial and space photographs are employed in the mapping of floodplain soils of West Siberia, with reliance placed upon indirect interpretation keys. Particularly important among the latter are terrain features and vegetation. Considerable attention is devoted to a description of the variation of the percentage compositions of various alluvial soil types under different terrain and vegetation conditions and the problems inherent in the selection of scale and of the taxonomic level(s) serving as basic units of mapping. Translated by Elliott Urdang, Providence, RI 02906 from: Aerokosmicheskiye metody v pochvovedenii i ikh ispol'zovaniye v sel'skom khozyaystve [Remote Sensing Methods in Soil Science and Their Utilization in Agriculture: A Collection of Scientific Works]. Moscow: Nauka, 1990, pp. 128–134.

The purpose of this study was to investigate radionuclide composition of the hot particles found in the floodplain of the Yenisei River and to discuss their possible sources. Since 1995, researchers of the Institute of Biophysics have found a considerable number of hot particles that contain up to 29,000 kBq/particle of 137Cs in the Yenisei River floodplain. Investigations of the particles in Krasnoyarsk, Moscow, and Novosibirsk have confirmed their reactor origin and made it possible to roughly estimate their age. Based on comparative analysis of 137Cs/134Cs ratios, all the particles can be divided into two or three major groups, suggesting that over the 50-year period of the MCC operation, there have been two or three emergency situations at the MCC reactors, with nuclear fuel microparticles released into the Yenisei. Microparticles containing up to 36 Bq/particle of 241Am were detected in soil and sediment samples collected at the Yenisei River. In some of these particles the 137Cs/241Am ratio is high but in the others — low. It remains unknown how these particles have been formed. However, these microparticles occur in floodplain soils and sediments very frequently and, thus, can be considered to be the main form in which radionuclides are present in the Yenisei River floodplain. The presence of a large number of hot particles of different origin in the floodplain of the Yenisei River from the MCC production area down to the town of Yeniseisk (and, probably, farther downstream) is a source of potential health hazard to people.

Because of past mining activities, the floodplains of the River Geul are polluted with heavy metals. The continuous supply of fresh sediments during floods has caused the floodplain soils to exhibit large quality variations in time. By measurements of (137)Cs deposition rates in part of the floodplain area were determined at 0.4 to 2.7 cm yr(-1). Analysis of soil metal concentrations at various depths at 65 locations, revealed that the upper 40 cm of the soil profile deposited during the past 30-45 yr, exhibit the highest metal levels. The geostatistical interpolation technique kriging was used to map actual and past pollution patterns. It was shown that, as a result of variable deposition rates, the spatial correlation structure of soil metal concentrations becomes less clear with increasing depth/age. Kriged maps of average metal concentrations in the upper 100 cm of the soil profile provided the basis for the calculation of the mass storage of heavy metals.

Initial soil development in river floodplains influences soil properties and processes. In this study, suites of young floodplain soils sampled at three European rivers (Danube/Austria, Ebro/Spain and Elbe/Germany) were used to link soil development to the soils’ retention capacity for cadmium. Geochemichal fractionation of original and metal-spiked soils was conducted. Cadmium remained in weakly bound fractions in both original and spiked soils, representing an entirely different behaviour than observed for copper in an earlier study. The tendency of incorporation into more stable forms over time was only slightly expressed. Correlation analysis revealed the involvement of different sorption surfaces in soil, with no single soil constituent determining cadmium retention behaviour. Nevertheless, in the calcareous soils of the Danube floodplain, we found increased cadmium retention and decreased portions of desorbable cadmium with progressing soil development.

No Abstract.Discovery and INnovation Vol. 18 (4) 2006: pp. 288-294

Five soil profiles were studied along a soil sequence in the Niger river floodplain to determine their soil properties and water-stable aggregates (WSA) between 4.75-2.00 mm, 2.00-1.00 mm, 1.00-0.50 mm, 0.50-02.5 mm and Key words: Soil organic carbon, Water-stable aggregates, Floodplain, C/N ratio, Soil profile. Agro-Science Vol.2(2) 2001: 52-61

Trace elements are potentially toxic to human life and the environment. Element toxicity depends on chemical associations in soils. Therefore, determining the chemical form of an element in soils is important to evaluate its mobility and bioavailability. Initial soil development in river floodplains influences soil properties, processes and therefore behavior of trace elements. In this study, three different floodplain soils sampled at three rivers (Nile/Egypt, Elbe/Germany and Penios/Greece) were used to link soil development and properties to the geochemical fractions and mobility of some trace elements. Sequential extraction was used to fractionate five trace elements (Cd, Cu, Ni, Pb and Zn) into five operationally defined groups: water soluble + exchangeable, carbonate, Fe-Mn oxide, organic, and residual. German soil showed the highest total concentration of the studied elements (except Ni). The Greek soil had the greatest amount of Ni. The residual fraction was the abundant pool for the studied elements examined in the Egyptian and Greek soils while the non-residual fraction was the dominant pool for all elements in the German soil. A significant amount (71- 94%) of all elements was present in German soil in the potentially available fraction: non-residual fraction, while the amount of this fraction ranged between 9 and 39 % in Greek soil and between 9 and 34 % in Egyptian soil. These suggest that the potential availability of the studied trace elements was extremely high in German soil compared to the Egyptian and Greek soil. In the German soil, most of the non-residual Cd, Ni and Zn were bounded with the Fe-Mn oxide fraction, while Cu and Pb distributed in the organic fraction. While in the Egyptian and Greek soils Fe-Mn oxide fraction was the abundant pool for the studied elements except for Cd, in which the exchangeable and the carbonate fractions had the greatest amount of Cd. Assuming that mobility and bioavailability of these elements are related to their solubility and geochemical forms, and that they decrease in the order of extraction sequence, the apparent mobility and potential bioavailability for the studied elements in the soils were: Cu > Cd > Ni ≥ Pb = Zn in Egyptian soil, Cd > Cu > Pb> Ni = Zn in Greek soil and Cd > Zn> Pb> Cu > Ni in German soil.

In large river floodplains, the high nutrient cycling capacity of floodplain soils, compared to that of upland ecosystems, is the consequence of energy and matter fluxes via flood deposits, These fluxes are under the control of local geomorphological features and the water regime. In this paper we illustrate how the geomorphological context of large river floodplains controls, both directly and indirectly, the nitrogen cycling within alluvial soils and, in turn, how it affects upstrcam/downstream fluxes of nitrogen.

Specimens of southwestern cupgrass (Eriochloa acuminata (C. Presl) Kunth var. acuminata) were collected in Ellis County, Kansas, in 1992 and 1993. Hundreds of plants were observed growing in cultivated and disturbed sites covering at least 20 acres of floodplain soils on the Kansas State University Agricultural Research Center-Hays. Occurrence of this species on land associated with agricultural production suggests that initial introduction probably resulted from human transport of agricultural products. The adaptability of southwestern cupgrass to disturbed environments, plus reports of its weediness in other states, indicate that the species has potential as a pest in Kansas.

A number of experiments were conducted at the Farming Systems Research and Development (FSRD) site, Palima, Tangail for three consecutive years to evaluate the efficiency of USG application in comparison with prilled urea on the yield and yield attributes of cabbage (cv. Atlas-70). There were five treatments, T 1 = N 195 (recommended N dose for HYG, used as prilled urea), T 2 = N195 (recommended N dose for HYG, used as USG), T 3 =N 175 (N 10% reduction of recommended N dose as USG), T 4 = N 155 (N 20% reduction of recommended N dose as USG), and T 5 = N 105 (Farmers' N dose used as prilled urea). Treatments T l -T 4 received recommended dose of other nutrients (P 56 K 162 S 13 Mo 0.6 CD 3t ) and T 5 received P 25 K 90 S 0 Mo 0 CD 51 Yield and yield-contributing characters of cabbage significantly responded to the application of USG. The highest head yield (78.1 t/ha) was obtained with the recommended dose of N as USG, and 10% (77.1 t/ha), and 20% (72.0 t/ha) less than the recommended dose of N as USG also produced higher yield than recommended prilled urea-N. Application of USG was found more efficient than prilled urea and the treatment N 195 P 56 K 162 S 13 Mo 0.6 CD 3t (recommended N as USG for HYG) was found profitable for cabbage cultivation in terms of yield and the treatment N 175 P 56 K 162 S 13 Mo 0.6 CD 3t (10% N reduction of recommended N dose as USG) was found profitable in terms of economic returns. Keywords: USG; prilled urea; cabbage. DOI: 10.3329/bjar.v35i2.5889 Bangladesh J. Agril. Res. 35(2) : 267-272, June 2010

The possibility of interpreting waterlogged soils using scanner imagery of Voronezh and Smolensk oblasts and Krasnodar Kray from the Resurs-01 satellite is investigated. Reliable interpretation keys are described for waterlogged floodplain soils and hydromorphic soils of agricultural fields have reliable interpretation criteria.