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Registros recuperados: 11
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Amazonian former gold mined soils as a source of methylmercury: Evidence from a small scale watershed in French Guiana ArchiMer
Guedron, Stephane; Grimaldi, Michel; Grimaldi, Catherine; Cossa, Daniel; Tisserand, Delphine; Charlet, Laurent.
Total mercury (HgT) and monomethylmercury (MMHg) were investigated in a tropical head watershed (1 km(2)) of French Guiana. The watershed includes a pristine area on the hill slopes and a former gold mined flat in the bottomland. Concentrations of dissolved and particulate HgT and MMHg were measured in rain, throughfall, soil water and at three points along the stream. Samples were taken in-between and during 14 storm events at the beginning and middle of the 2005 and 2006 rainy seasons. Dissolved and particulate HgT concentrations in the stream slightly increased downstream, while dissolved and particulate MMHg concentrations were low at the pristine sub-watershed outlet (median = 0.006 ng L-1 and 1.84 ng g(-1), respectively) and sharply increased at the...
Tipo: Text Palavras-chave: Mercury; Methylmercury; Tropical watershed; Gold placers; Stream water; Oxisols; Hydromorphic soils.
Ano: 2011 URL: http://archimer.ifremer.fr/doc/00035/14628/12134.pdf
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High genetic diversity among and within bitter manioc varieties cultivated in different soil types in Central Amazonia Genet. Mol. Biol.
Alves-Pereira,Alessandro; Peroni,Nivaldo; Cavallari,Marcelo Mattos; Lemes,Maristerra R.; Zucchi,Maria Imaculada; Clement,Charles R..
Abstract Although manioc is well adapted to nutrient-poor Oxisols of Amazonia, ethnobotanical observations show that bitter manioc is also frequently cultivated in the highly fertile soils of the floodplains and Amazonian dark earths (ADE) along the middle Madeira River. Because different sets of varieties are grown in each soil type, and there are agronomic similarities between ADE and floodplain varieties, it was hypothesized that varieties grown in ADE and floodplain were more closely related to each other than either is to varieties grown in Oxisols. We tested this hypothesis evaluating the intra-varietal genetic diversity and the genetic relationships among manioc varieties commonly cultivated in Oxisols, ADE and floodplain soils. Genetic results did...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Manihot esculenta; Microsatellites; Amazonian dark earths; Floodplain; Oxisols.
Ano: 2017 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572017000300468
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Magnetic and spectral signatures of Cerrado soils in the state of Goiás, Brazil PAB
Fernandes,Kathleen Lourenço; Ribon,Adriana Aparecida; Marques Junior,José; Bahia,Angélica Santos Rabelo de Souza; Tavares Filho,João.
Abstract: The objective of this work was to estimate the iron oxide contents (hematite and goethite) and to characterize the color and the spectral and magnetic signatures of Cerrado soils in the state of Goiás, Brazil. Six Oxisols and one Inceptisol were studied. Spectral and magnetic signatures were determined by diffuse reflectance spectroscopy (DRS) and magnetic susceptibility, respectively. Then, the spectral curves and the second derivative calculations were used to determine hematite and goethite contents, as well as soil color after conversion into tristimulus values. Hematite and goethite contents were also obtained by x-ray diffractometry, and soil color was also defined in the field (Munsell color chart). The values for the isomorphic...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Diffuse reflectance spectroscopy; Goethite; Hematite; Magnetic susceptibility; Oxisols.
Ano: 2017 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2017001000923
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Organic Carbon and Physical Properties in Sandy Soil after Conversion from Degraded Pasture to Eucalyptus in the Brazilian Cerrado Rev. Bras. Ciênc. Solo
Sena,Karla Nascimento; Maltoni,Kátia Luciene; Faria,Glaucia Amorim; Cassiolato,Ana Maria Rodrigues.
ABSTRACT Soil is currently seen as the most relevant carbon sink and the most effective carbon stabilizer. In contrast, agriculture is the second largest C emitter, after burning of fossil fuels. This organic carbon (OC) introduced into the soil, mainly via organic matter (OM), is essential for several soil properties and plays an extremely important role in sandy soils. The objective of this study was to describe the changes in the amounts and pools of OC and the influence thereof on some physical soil properties in areas converted from pasture to eucalyptus. The following areas were analyzed: a degraded pasture (PAST), two areas of pasture-eucalyptus conversion after 2 and 15 years (EU02 and EU15, respectively) and a preserved Cerrado area (CER) in the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Aggregate stability; Carbon pool; Oxisols; Anthropogenic soils.
Ano: 2017 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832017000100518
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Quality reference values for rare earth elements in soils from one of the last agricultural frontiers in Brazil Scientia Agricola
Silva,Yuri Jacques Agra Bezerra da; Oliveira,Eliabe Barros de; Silva,Ygor Jacques Agra Bezerra da; Nascimento,Clístenes Williams Araújo do; Silva,Tatiana dos Santos; Boechat,Cácio Luiz; Teixeira,Marcos Paulo Rodrigues; Barbosa,Ronny Sobreira; Singh,Vijay P.; Sena,Antonny Francisco Sampaio de.
ABSTRACT: Environmental impacts caused by the addition of rare earth elements (REEs) to agricultural soils are a growing concern. The sedimentary basin of the Gurguéia River is located in one of the last agricultural frontiers in Brazil; nevertheless, data regarding quality reference values (QRVs) for REEs in soils are still scarce. The objective of this study was therefore to determine the natural concentration and establish the QRVs of REEs in soils of Gurguéia watershed, Brazil. Fifty-five composite soil samples were collected at sites under no or minimal anthropic interference. The average REE natural concentrations in soils from the Gurguéia watershed were lower than those found in other regions of Brazil and worldwide, following the order (mg kg−1):...
Tipo: Info:eu-repo/semantics/article Palavras-chave: REE geochemistry; Gurguéia watershed; Oxisols; Lanthanides.
Ano: 2021 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162021000701401
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Reforested soil under drip irrigation with treated wastewater from poultry slaughterhouse AGRIAMBI
Araujo,Izabela R. C.; Sampaio,Silvio C.; Paz-Gonzalez,Antonio; Vilas-Boas,Márcio A.; Gonçalves Junior,Affonso C.; Szekut,Flávio D..
ABSTRACT The disposal of treated effluents on soil is the main final use of wastewater in Brazil. Although this practice can promote improvements of some soil attributes, there is a need for monitoring in order to ensure that potential environmental impacts are not harmful. Thus, the purpose of this study was to evaluate the effects of treated effluent from a poultry slaughterhouse on the chemical attributes of an Oxisols, in Matelândia-PR, Brazil under drip irrigation. The soil attributes P, K, Fe, Cu, Zn, Mn, pH in CaCl2, H + Al, Al, Ca, Mg, cation exchange capacity (CEC), and percent base saturation (V) were evaluated under four effluent application rates, 0, 100, 200 and 300 m³ ha-1 d-1 with treated effluents on three successive sampling dates. As main...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Forestry production; Eucalyptus; Oxisols.
Ano: 2019 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662019000600439
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Sampling and TDR probe insertion in the determination of the volumetric soil water content Rev. Bras. Ciênc. Solo
Teixeira,W. G.; Schroth,G.; Marques,J. D.; Huwe,Bernd.
Volumetric soil water content (theta) can be evaluated in the field by direct or indirect methods. Among the direct, the gravimetric method is regarded as highly reliable and thus often preferred. Its main disadvantages are that sampling and laboratory procedures are labor intensive, and that the method is destructive, which makes resampling of a same point impossible. Recently, the time domain reflectometry (TDR) technique has become a widely used indirect, non-destructive method to evaluate theta. In this study, evaluations of the apparent dielectric number of soils (epsilon) and samplings for the gravimetrical determination of the volumetric soil water content (thetaGrav) were carried out at four sites of a Xanthic Ferralsol in Manaus - Brazil. With the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Amazon; Oxisols; Time domain reflectometry; Dieletric properties.
Ano: 2003 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832003000400001
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Soils and agriculture in central-west and north Brazil Scientia Agricola
Buol,Stanley W..
Modern soil science, spearheaded by research in Brazil has facilitated the utilization of vast areas of previously uncultivated soil long considered unsuitable for human food production into highly productive agricultural land. Naturally acid soils with high contents of aluminum and iron oxides and low CEC values and organic matter contents long considered insurmountable obstacles to crop production in tropical latitudes could be extremely productive. With continued development of the infrastructure needed by commercial agriculture Brazil has the potential to lead the world in its quest to provide food for growing human populations.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Cerrado soils; Brazilian Amazon; Latossolos; Oxisols; Ultisols.
Ano: 2009 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162009000500016
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Soybean yield in response to application of phosphate rock associated with triple superphosphate Scientia Agricola
Oliveira Júnior,Adilson de; Prochnow,Luís Ignácio; Klepker,Dirceu.
Soybean (Glycine max L. Merrill) crop started to be planted in the Brazilian Cerrado in the 1970's, and this region currently contributes with 57% of total soybean production in Brazil. Under natural conditions in this region, the soils present chemical limitations such as low pH, low Cation Exchange Capacity, low nutrient availability, and moreover, clayey soils have a high P fixation capacity mainly due to high contents of Fe/Al oxides. Since P is the most limiting nutrient is this region, a study was performed in the state of Maranhão, Brazil, in a Typic Hapludox, with clayey texture and low available P (extracted by resin). Treatments were defined to evaluate soybean response to broadcast Arad phosphate rock (PR) plus banded triple superphosphate (TSP)...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Brazil; Glycine max L. Merrill; Oxisols; P source solubility; Phosphorus; Cerrado soils.
Ano: 2011 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162011000300016
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Surface Complexation Modeling in Variable Charge Soils: Charge Characterization by Potentiometric Titration Rev. Bras. Ciênc. Solo
Marchi,Giuliano; Vilar,Cesar Crispim; O’Connor,George; Silva,Marx Leandro Naves.
ABSTRACT Intrinsic equilibrium constants of 17 representative Brazilian Oxisols were estimated from potentiometric titration measuring the adsorption of H+ and OH− on amphoteric surfaces in suspensions of varying ionic strength. Equilibrium constants were fitted to two surface complexation models: diffuse layer and constant capacitance. The former was fitted by calculating total site concentration from curve fitting estimates and pH-extrapolation of the intrinsic equilibrium constants to the PZNPC (hand calculation), considering one and two reactive sites, and by the FITEQL software. The latter was fitted only by FITEQL, with one reactive site. Soil chemical and physical properties were correlated to the intrinsic equilibrium constants. Both surface...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Intrinsic equilibrium constants; Oxisols; FITEQL; Visual MINTEQ; Chemical equilibrium software.
Ano: 2015 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832015000501387
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Temporal stability of soil moisture under effect of three spacings in a eucalyptus stand Agronomy
Melo Neto, José de Oliveira; de Mello, Carlos Rogério; Silva, Antônio Marciano da; de Mello, José Márcio; Viola, Marcelo Ribeiro; Yanagi, Sílvia de Nazaré Monteiro.
Soil moisture temporal variability is an important concept in understanding forest management. The objective of this study was to analyse the effect of planting density on soil profile moisture in a clonal Eucalyptus plantation. Soil moisture was observed every 15 days at 25 points distributed throughout the eucalyptus stand between November 2013 and October 2015 to characterize the moisture according to the following three types of spacings: 3 x 2, 3 x 3, and 3 x 5 m. At each point, the 0 - 10, 10 - 20, 20 - 30, 30 – 40, and 60 - 100 cm layers were evaluated using a Profile Probe PR2 model. Soil moisture showed high spatial variability in the 0 - 10 cm layer, whereas from 30 to 100 cm deep, the moisture tended to become more homogeneous throughout the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: 5.02.01.07-7 planting density; Oxisols; Water storage in the soil profile; Minas Gerais; Solos Florestais.
Ano: 2017 URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/32656
Registros recuperados: 11
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