The combined use of reflectance, emissivity and elevation Aster/Terra data for tropical soil studies

Reflectance, emissivity and elevation data of the sensor ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer)/Terra were used to characterize soil composition variations according to the toposequence position. Normalized data of SWIR (shortwave infrared) reflectance and TIR (thermal infrared) emissivity, coupled to a soil-fraction image from a spectral mixture model, were evaluated to separate bare soils from nonphotosynthetic vegetation. Regression relationships of some soil properties with reflectance and emissivity data were then applied on the exposed soil pixels. The resulting estimated values were plotted on the ASTER-derived digital elevation model. Results showed that the SWIR bands 5 and 6 and the TIR bands 10 and 14 measured the clay mineral absorption band and the quartz emissivity feature, respectively. These bands improved also the discrimination between nonphotosynthetic vegetation and soils. Despite the differences in pixel size and field sampling size, some soil properties were correlated with reflectance (R² of 0.65 for Al2O3 in band 6; 0.61 for Fe2O3 in band 3) and emissivity (R² of 0.65 for total sand fraction in the 10/14 band ratio). The combined use of reflectance, emissivity and elevation data revealed variations in soil composition with topography in specific parts of the landscape. From higher to lower slope positions, a general decrease in Al2O3 and increase in total sand fraction was observed, due to the prevalence of Rhodic Acrustox at the top and its gradual transition to Typic Acrustox at the bottom.

OSL age determinations of Pleistocene fluvial deposits in Central Amazonia

Absolute dating methods have been used in chronological studies of geological processes and sedimentary units of Quaternary age in Central Amazonia, Brazil. Although radiocarbon dating has been very useful in archaeological research and soil studies, the temporal interval of this method is inefficient in evaluating the sedimentation aspects and geological events from the beginning of the Quaternary in the Amazon basin. The use of crystal luminescence dating has been one of the most promising tool for determining the absolute dating of Quaternary deposits in the Amazonian region. Optically stimulated luminescence (OSL) dating, following the MAR and SAR protocols, in a tectonic-sedimentary study of Quaternary fluvial deposits in the confluence area of the Negro and Solimões rivers, indicated ages from 1.3 (Holocene) to about 67.4 kyears (Late Pleistocene) for these sediments. Low radioactive isotope concentrations were found about 2ppm for 235U and 238U; 5ppm for 232Th; and the 40K concentrations were almost zero. A comparison was made between MAR and SAR protocols taking into account the fluvial depositional process.

Dispersion of natural arsenic in the Malcantone watershed, Southern Switzerland: field evidence for repeated sorption-desorption and oxidation-reduction processes

In recent years, elevated arsenic concentrations have been found in waters and soils of many, countries, often resulting in a health threat for the local population. Switzerland is not an exception and this paper deals with the release and subsequent fate of arsenic in a 200-km(2) mountainous watershed, characterized by crystalline silicate rocks (gneisses, schists, amphibolites) that contain abundant As-bearing sulfide ore deposits, some of which have been mined for iron and gold in the past. Using analytical methods common for mineralogical, ground water and soil studies (XRD, XRF, XAS-XANES and -EXAFS, electron microprobe, extraction, ICP, AAS with hydride generator, ion chromatography), seven different field situations and related dispersion processes of natural arsenic have been studied: (1) release by rock weathering, (2) transport and deposition by water and ice; (3) release of As to the ground and surface water due to increasing pH; (4) accumulation in humic soil horizons; (5) remobilization by reduction in water-saturated soils and stagnant ground waters; (6) remobilization by using P-rich fertilizers or dung and (7) oxidation, precipitation and dilution in surface waters. Comparison of the results with experimental adsorption studies and speciation diagrams from the literature allows us to reconstruct and identify the typical behavior of arsenic in a natural environment under temperate climatic conditions. The main parameters identified are: (a) once liberated from the primary minerals, sorption processes on Fe-oxy-hydroxides dominate over Al-phases, such as Al-hydroxides or clay minerals and limit the As concentrations in the spring and well waters between 20 and 300 mug/l. (b) Precipitation as secondary minerals is limited to the weathering domain, where the As concentrations are still high and not yet too diluted by rain and soils waters. (c) Although neutral and alkaline pH conditions clearly increase the mobility of As, the main factor to mobilize As is a low redox potential (Eh close or below 0 mV), which favors the dissolution of the Fe-oxy-hydroxides on which the As is sorbed. (d) X-ray absorption spectroscopy (XAS) of As in water-logged humic forest soils indicates that the reduction to As III only occurs at the solid-water interface and that the solid contains As as As V (e) A and Bh horizons of humic cambisols can effectively capture As when As-rich waters flow through them. Complex spatial and temporal variation of the various parameters in a watershed results in repeated mobilization and immobilization of As, which continuously transports As from the upper to the lower part of a watershed and ultimately to the ocean. (C) 2004 Elsevier B.V. All rights reserved.

Uranium-enrichment in soils and plants in the vicinity of a pitchblende vein at La Creusaz-Les Marecottes (W of Martigny, Valais, Switzerland)

In the NE part of the Aiguilles Rouges Massif near Martigny, at the eastern contact of the Variscan Vallorcine granite to adjacent gneisses, a series of pitchblende (UO2)-veins occur. This paper determines the level of enrichment and mobility of uranium in soils situated in the vicinity of such a UO2-vein 7 km west of Martigny. Within an area of 50 x 100 m, situated on a relatively steep slope and characterized by a strong gramma-ray anomaly, six soil profiles including their plant cover and a reference soil profile outside the influence of the UO2-vein have been examined. The soil shows pH-values between 4 and 5 and is colluvial. The applied analytical methods for the metal contents include extraction methods, common for soil studies, and bulk analysis performed with X-ray fluorescence and ICP-MS. Uranium contents found in the uppermost 20 cm of the soil profiles vary from 2,500 ppm close to the vein to 15 ppm at the lowermost point of the study area. The reference soil has around 3 ppm uranium. At greater depth (20 to 40 cm) the U-content decreases to about half of the surface values, indicating a vertical transport of uranium within the soil profile. No systematic dependance of uranium-contents to grain size (amount of clay) nor to the amount of organic matter has been found. However, the good correlation between uranium and free iron oxide concentration suggests adsorption of uranium on iron oxy-hydroxides. The ashes of grass and mosses contain up to 90 ppm U, the blueberry and redwood only up to 3 ppm. Our observations suggest that at the surface the uranium is transported by downhill creep (solifluxion) of uranium-rich rock fragments. Liberated by oxidation of the uppermost fragments in a given soil column, the uranium migrates vertically until the conditions are favourable to adsorption onto Fe-oxy-hydroxides. However, as high U-contents of local surface water show, this adsorption does not lead to a significant retention of the uranium.

Immobilization of laccase on hybrid layered double hydroxide

Crystals of Mg/Al layered double hydroxide were synthesized by alkaline precipitation and treated in an aqueous solution of glutamic acid. The glutamate ions were not intercalated into the interlayer space, but were detected in the material by Fourier transform infrared spectroscopy, suggesting that only the external surfaces of crystals were modified with glutamate ions. The resulting hybrid material was tested as a support for immobilization of the enzyme laccase (Myceliophthora thermophila). The immobilized enzyme preparation was characterized by electronic paramagnetic resonance spectroscopy and by assays of catalytic activity. The activity of the immobilized laccase was 97% of the activity in the free enzyme. Layered double hydroxide is a suitable support for use in remediation of soil studies.

Assessment of the CMD Mini-Explorer, a new low-frequency multi-coil electromagnetic device, for archaeological investigations

In this article we assess the abilities of a new electromagnetic (EM) system, the CMD Mini-Explorer, for prospecting of archaeological features in Ireland and the UK. The Mini-Explorer is an EM probe which is primarily aimed at the environmental/geological prospecting market for the detection of pipes and geology. It has long been evident from the use of other EM devices that such an instrument might be suitable for shallow soil studies and applicable for archaeological prospecting. Of particular interest for the archaeological surveyor is the fact that the Mini-Explorer simultaneously obtains both quadrature (‘conductivity’) and in-phase (relative to ‘magnetic susceptibility’) data from three depth levels. As the maximum depth range is probably about 1.5 m, a comprehensive analysis of the subsoil within that range is possible. As with all EM devices the measurements require no contact with the ground, thereby negating the problem of high contact resistance that often besets earth resistance data during dry spells. The use of the CMD Mini-Explorer at a number of sites has demonstrated that it has the potential to detect a range of archaeological features and produces high-quality data that are comparable in quality to those obtained from standard earth resistance and magnetometer techniques. In theory the ability to measure two phenomena at three depths suggests that this type of instrument could reduce the number of poor outcomes that are the result of single measurement surveys. The high success rate reported here in the identification of buried archaeology using a multi-depth device that responds to the two most commonly mapped geophysical phenomena has implications for evaluation style surveys. Copyright © 2013 John Wiley & Sons, Ltd.

Variabilidade espacial de propriedades dendrométricas do eucalipto e de atributos físicos de um Latossolo Vermelho

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A abordagem fractal em Geociencias

This is a synthesis of the use of fractal approaches in geosciences. It presents references and a list of publications, taking into account sectors of many fields, including geophysics, petrology, mineralogy, sedimentology, tectonics, meteorology, climatology, geomorphology, hydrogeology, oceanography, geomechanics, geochemistry and soil studies. -English summary

Doses e formas de aplicação de molibdênio na cultura do milho

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação de um escarificador em função dos tipos de haste e profundidades de trabalho

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

X-Ray Diffraction Studies of Soils and Soil Stabilizers, HR-106, 1965

The two goals of this project stated in the Proposal were: (1) study lime diffusion in clayey soils, and (2) find the role of MgO in soil-dolomitic lime stabilization. Because of the practice significance of these goals we temporarily overstaffed this project, giving somewhat a "crash" program. As a result, proposed work was finished up early (as were the funds), and more important, some of the findings were early enough and of sufficient merit to put into field trials in the Fall of 1964. The work now being completed and the funds all being expended, this Final Report is therefore submitted before the anticipated project termination date.

Studies on Soil-Aggregate-Sodium Chloride Stabilized Roads in Franklin County, Iowa, HR-33

This investigation was conducted to study the performance characteristics of low cost roadway surfaces of soil-aggregate-sodium chloride mixtures. Many roads have been successfully stabilized with sodium chloride. However, little information is available on either the properties of the road materials or the effects of sodium chloride on the materials. The performance of some of the sodium chloride stabilized roads in Franklin County, Iowa, and the performance of some near-by nonchemically treated roads has been studied. The study of sodium chloride stabilized roads was restricted to the roads in which the binder soil used in construction came from the same source. The effects of sodium chloride on some of the engineering properties of the soil and soil-aggregate mixtures used were studied in the laboratory.

Missouri River Studies: Alluvial Morphology and Engineering Soil Classification, HR-1, Progress Report, 1960

The primary purposes of this investigation are: 1) To delineate flood plain deposits with different geologic and engineering properties. 2) To provide basic data necessary for any attempt at stabilizing flood plain deposits. The alluvial valley of the Missouri River adjacent to Iowa was chosen as the logical place to begin this study. The river forms the western boundary of the state for an airline distance of approximately 139 miles; and the flood plain varies from a maximum width of approximately 18 miles (Plates 2 and 3, Sheets 75 and 75L) to approximately 4 miles near Crescent, Iowa (Plate 8, Sheet 66). The area studied includes parts of Woodbury, Monona, Harrison, Pottawattamie, Mills, and Fremont counties in Iowa and parts of Dakota, Thurston, Burt, Washington, Douglas, Sarpy, Cass and Otoe counties in Nebraska. Plate l is an index map of the area under consideration.

Studies On Strength Characteristics Of Soil Mixed With Bio-Waste

Researches are always in quest for finding innovative methods for ground improvement using sustainable and environmental friendly solutions. Theproduction of large quantity of biowastes all over the world faces serious problems of handling and disposal. Coir pith is a biowaste from coir industry and sugarcane baggase is another biowaste obtained after extractingjuice from sugar cane. So the present study is an investigation into the effect of coir pith and sugarcane baggase on some geotechnical properties of red earth. The investigation includes study on variation of properties such as O.M.C, maximum dry density, C.B.R. values,unconfined compressive strength and permeability when these materials are included in soil. Several conclusions are arrived at, on the basis of the experiments conducted and it may be helpful for predicting the behavior of such soil matrix

Studies on Landfill Leachate Transportation and Its Impact on Soil Characteristics

Leachate from an untreated landfill or landfill with damaged liners will cause the pollution of soil and ground water. Here an attempt was made to generate knowledge on concentrations of all relevant pollutants in soil due to municipal solid waste landfill leachate and its migration through soil and also to study the effect of leachate on the engineering properties of soil. To identify the pollutants in soil due to the leachate generated from municipal solid waste landfill site, a case study on an unlined municipal solid waste landfill at Kalamassery has been done. Soil samples as well as water samples were collected from the site and analysed to identify the pollutants and its effect on soil characteristics. The major chemicals in the soil were identified as Ammonia, Chloride, Nitrate, Iron, Nickel, Chromium, Cadmium etc.. Engineering properties of field soil samples show that the chemicals from the leachate of landfill may have effect on the engineering properties of soil. Laboratory experiments were formulated to model the field around an unlined MSW landfill using two different soils subjected to a synthetic leachate. The Maximum change in chemical concentration and engineering property was observed on soil samples at a radial distance of 0.2 m and at a depth of 0.3 m. The pollutant (chemicals) transport pattern through the soil was also studied using synthetic leachate. To establish the effect of pollutants (chemicals) on engineering properties of soil, experiments were conducted on two types soils treated with the synthetic chemicals at four different concentrations. Analyses were conducted after maturing periods of 7, 50, 100 and 150 days. Test soils treated with maximum chemical concentration and matured for 150 days were showing major change in the properties. To visualize the flow of pollutants through soil in a broader sense, the transportation of pollutants through soil was modeled using software ‘Visual MODFLOW’. The actual field data collected for the case study was used to calibrate the modelling and thus simulated the flow pattern of the pollutants through soil around Kalamassery municipal solid waste landfill for an extent of 4 km2. Flow was analysed for a time span of 30 years in which the landfill was closed after 20 years. The concentration of leachate beneath the landfill was observed to be reduced considerably within one year after closure of landfill and within 8 years, it gets lowered to a negligible level. As an environmensstal management measure to control the pollution through leachate, permeable reactive barriers are used as an emerging technology. Here the suitability of locally available materials like coir pith, rice husk and sugar cane bagasse were investigated as reactive media in permeable reactive barrier. The test results illustrates that, among these, coir pith was showing better performance with maximum percentage reduction in concentration of the filtrate. All these three agricultural wastes can be effectively utilized as a reactive material. This research establishes the influence of leachate of municipal solid waste landfill on the engineering properties of soil. The factors such as type of the soil, composition of leachate, infiltration rate, aquifers, ground water table etc., will have a major role on the area of influence zone of the pollutants in a landfill. Software models of the landfill area can be used to predict the extent and the time span of pollution of a landfill, by inputting the accurate field parameters and leachate characteristics. The present study throws light on the role of agro waste materials on the reduction of the pollution in leachate and thus prevents the groundwater and soil from contamination