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Relationship between soil oxidizable carbon and physical, chemical and mineralogical properties of umbric ferralsols; Relações entre o carbono oxidável do solo e atributos físicos, químicos e mineralógicos de latossolos com horizonte a húmico

MARQUES, Flávio Adriano; CALEGARI, Márcia Regina; VIDAL-TORRADO, Pablo; BUURMAN, Peter
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
38.09%
The occurrence of Umbric Ferralsols with thick umbric epipedons (> 100 cm thickness) in humid Tropical and Subtropical areas is a paradox since the processes of organic matter decomposition in these environments are very efficient. Nevertheless, this soil type has been reported in areas in the Southeast and South of Brazil, and at some places in the Northeast. Aspects of the genesis and paleoenvironmental significance of these Ferralsols still need a better understanding. The processes that made the umbric horizons so thick and dark and contributed to the preservation of organic carbon (OC) at considerable depths in these soils are of special interest. In this study, eight Ferralsols with a thick umbric horizon (UF) under different vegetation types were sampled (tropical rain forest, tropical seasonal forest and savanna woodland) and their macromorphological, physical, chemical and mineralogical properties studied to detect soil characteristics that could explain the preservation of high carbon amounts at considerable depths. The studied UF are clayey to very clayey, strongly acidic, dystrophic, and Al-saturated and charcoal fragments are often scattered in the soil matrix. Kaolinites are the main clay minerals in the A and B horizons...

Soil structure transformations from ferralic to nitic horizons on a toposequence in southeastern Brazil; Transformações da estrutura entre horizontes blatossólico e B nítico em uma topossequência no sudeste do Brasil

COOPER, Miguel; VIDAL-TORRADO, Pablo; GRIMALDI, Michel
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
16.74%
The soil structure transformation from ferralic to nitic horizons was studied in a toposequence on quaternary red clayey sediments and diabase in Piracicaba (SP), Brazil. Morphological and micromorphological studies, image analysis, soil water characteristic curves and monitoring of (total) soil water potential head were used. The presence of polyconcave vughs, clayskins and planar voids shows that the vertical and lateral transition and structural transformation from ferralic to nitic horizons is given by the coalescence of the microaggregates, probably due to tensions created in a drier period in the past. Changes to a more humid climate with a defined dry season and alternate drying and wetting cycles resulted in the fissuration of the previously coalesced material, forming polyhedral aggregates and microaggregates. Simultaneously, clay illuviation filled the voids and together with the compacting action of the biological activity of these soils contributed to the coalescence of microaggregates.; A transformação estrutural entre horizontes B latossólico e B nítico foi estudada numa topossequência sobre sedimentos vermelhos quaternários e diabásio em Piracicaba (SP). Estudos morfológicos e micromorfológicos, análises de imagem...

Contribution of soil organic carbon to the ion exchange capacity of tropical soils

SOARES, Marcio Roberto; ALLEONI, Luis Reynaldo Ferracciu
Fonte: HAWORTH PRESS INC Publicador: HAWORTH PRESS INC
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
16.74%
Highly weathered soils represent about 3 billion ha of the tropical region. Oxisols represent about 60% of the Brazilian territory (more than 5 million km 2), in areas of great agricultural importance. Soil organic carbon (SOC) can be responsible for more than 80% of the cation exchange capacity (CEC) of highly weathered soils, such as Oxisols and Ultisols. The objective of this study was to estimate the contribution of the SOC to the CEC of Brazilian soils from different orders. Surface samples (0.0 to 0.2 m) of 30 uncultivated soils (13 Oxisols, 6 Ultisols, 5 Alfisols, 3 Entisols, I Histosol, 1 Inceptisol. and I Molisol), under native forests and from reforestation sites from Sao Paulo State, Brazil, were collected in order to obtain a large variation of (electro)chemical, physical, and mineralogical soil attributes. Total content of SOC was quantified by titulometric and colorimetric methods. Effective cation exchange capacity (ECEC) was obtained by two methods: the indirect method-summation-estimated the ECECi from the sum of basic cations (Ca+ Mg+ K+ Na) and exchangeable Al; and the direct ECECd obtained by the compulsive exchange method, using unbuffered BaCl2 solution. The contribution of SOC to the soil CEC was estimated by the Bennema statistical method. The amount of SOC var ied from 6.6 g kg(-1) to 213.4 g kg(-1). while clay contents varied from 40 g kg(-1) to 716 g kg(-1). Soil organic carbon contents were strongly associated to the clay contents...

Matéria orgânica de Latossolos com horizonte A húmico; Organic matter of the Ferralsols wiht umbric epipedon

Marques, Flávio Adriano
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 02/02/2010 PT
Relevância na Pesquisa
37.94%
Latossolos com horizonte A húmico (LH) são solos com importantes reservas de carbono orgânico (CO) em profundidade. Esses solos são comuns nas regiões Sudeste e Sul do Brasil, com menor ocorrência no Nordeste. Aspectos da gênese e preservação da matéria orgânica (MO) desses solos não foram completamente entendidos ainda. Particularmente interessantes são os processos responsáveis pelo espessamento (hiperdesenvolvimento) e estabilidade do CO do horizonte húmico. A hipótese de que a MO do horizonte húmico tenha importante contribuição de carbono (C) de origem pirogênica é testada. O objetivo deste trabalho foi, portanto, caracterizar quimicamente a MO do horizonte húmico e relacionar os resultados com a gênese e preservação do CO. Oito pedons de diferentes localidades do país (São Paulo, Rio de Janeiro, Minas Gerais, Paraná, Santa Catarina e Pernambuco) sob vegetação nativa foram empregados no estudo. Descrições morfológicas e análises de caracterização de rotina dos solos foram realizadas. Além disso, ácidos húmicos (AH) foram extraídos do horizonte húmico e analisados por ressonância magnética nuclear de 13C, enquanto que as frações leves (livre e oclusa), huminas e extratos alcalinos da MO dos mesmos pedons foram analisados através da pirólise. Os pedons possuem feições morfológicas conspícuas...

Desenvolvimento de funções de pedotransferência e sua utilização em modelo agro-hidrológico; Development of pedotransfer functions and their application in agrohydrological models

Barros, Alexandre Hugo Cezar
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 25/08/2010 PT
Relevância na Pesquisa
16.74%
Foram desenvolvidas funções de pedotransferência (PTF) para estimar os parâmetros ('alfa', n 'teta'r e 'teta's) do modelo de Van Genuchten (1980) utilizado para descrever curvas de retenção de água no solo. Os dados utilizados foram provenientes de diversas fontes, principalmente de estudos realizados na região Nordeste pelas Universidades, Embrapa e Codevasf, totalizando 786 curvas de retenção, as quais foram divididas em dois conjuntos de dados: 85% para desenvolvimento das PTF; e 15% para teste e validação, considerados como dados independentes. Além do desenvolvimento das PTF de caráter generalizado para todos os solos, foram desenvolvidas PTF específicas para as classes Argissolos, Latossolos, Neossolos e Planossolos. As PTF foram desenvolvidas utilizando técnicas de regressão múltipla, utilizando o procedimento stepwise (forward e backward) para selecionar os melhores preditores. Duas PTF foram desenvolvidas: a) incluindo todos os preditores, densidade do solo, teores de areia, silte e argila e de matéria orgânica e b) apenas com os teores de areia, silte e argila. A avaliação estatística das PTF foi feita de acordo o coeficiente de determinação (R2), o índice de Willmott (d) e o índice confiança (IC). Para avaliação da estimativa do teor de água em potenciais matriciais específicos foi utilizado a raiz do erro médio quadrado (RMSE). A avaliação funcional das PTF paramétricas foi realizada examinando o seu desempenho no contexto do modelo SWAP (Soil-Water-Atmosphere-Plant). Os parâmetros s...

Dinâmica da atrazina e da mesotriona em solos : degradação acelerada, sorção e implicações ambientais; Dynamic of atrazine and mesotrione in soils: accelerated degradation, sorption, and environmental fate implications

Martinazzo, Rosane
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Tese de Doutorado Formato: application/pdf
POR
Relevância na Pesquisa
17.73%
O solo é um dos principais destinos finais dos pesticidas e, portanto, a dinâmica desses compostos no solo pode determinar a extensão de seus efeitos aos organismos alvo e ao ambiente como um todo. Sendo assim, dois estudos foram realizados para avaliar a dinâmica da atrazina e a sorção da mesotriona em solos, e estimar o risco potencial de contaminação desses herbicidas ao ambiente. No primeiro, investigou-se a mineralização e a formação de metabólitos e de resíduos não-extraíveis de 14C-atrazina em latossolos com diferentes históricos de aplicação do herbicida, sob condições insaturadas e sob alagamento. No segundo, avaliou-se a sorção de atrazina e de mesotriona em seis latossolos e estimou-se o potencial contaminante dos herbicidas por meio de modelos de avaliação de risco. No estudo I observou-se que latossolos com histórico de aplicação de atrazina apresentaram elevado potencial de mineralização desse herbicida. Após 85 dias de incubação, 82% da 14C-atrazina aplicada foi mineralizada no Latossolo Vermelho (LV-T) e 74% no Latossolo Vermelho Amarelo (LVA-T), sendo a meia-vida do herbicida 2,8 e 21,2 dias respectivamente. Nos solos sem histórico de aplicação de atrazina a mineralização foi baixa (≤ 5...

Tempo de uso agrícola e propriedades químicas de dois latossolos do Planalto Médio do Rio Grande do Sul; Time of agricultural use and chemical properties of two ferralsols in the Planalto Médio region of the State of Rio Grande do Sul, Brazil

Perin, Edevar; Ceretta, Carlos Alberto; Klamt, Egon
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
POR
Relevância na Pesquisa
27.73%
Os Latossolos, que predominam na região do Planalto Médio do Rio Grande do Sul sob vegetação de mata, foram incorporados ao uso agrícola a partir de 1920, enquanto os solos sob vegetação de campo foram explorados a partir da década de 1960. Estes solos sofreram alterações em suas propriedades químicas com o intenso uso agrícola, principalmente com culturas anuais como soja e milho. Este estudo teve como objetivo avaliar a influência do tempo de uso agrícola sobre propriedades químicas de dois Latossolos, no município de Fortaleza dos Valos (RS). Coletaram-se amostras de perfis de um Latossolo Vermelho distrófico típico (LVd) textura argilosa e de Latossolo Vermelho distrófico típico (LVd) textura média, sob cobertura vegetal natural de floresta e campo, respectivamente, em situação de topo de coxilha e de perfis destes solos sob uso agrícola por períodos que variaram de oito até mais de 33 anos. Foram determinados os teores de argila, matéria orgânica, P e K disponíveis e totais, Ca, Mg e Al trocáveis e pH. Calculou-se a saturação por bases (V) e por alumínio (m). Os resultados mostraram que a diminuição no teor de matéria orgânica do solo com o tempo de uso agrícola foi perceptível, quando originalmente os solos eram de florestas...

Different responses in bulk density and saturated hydraulic conductivity to soil deformation by logging machinery on a Ferralsol under native forest

Schack-Kirchner, H.; Fenner, P. T.; Hildebrand, E. E.
Fonte: Blackwell Publishing Publicador: Blackwell Publishing
Tipo: Artigo de Revista Científica Formato: 286-293
ENG
Relevância na Pesquisa
17.39%
Ferralsols have high structural stability, although structural degradation has been observed to result from forest to tillage or pasture conversion. An experimental series of forest skidder passes in an east Amazonian natural forest was performed for testing the effects of mechanical stress during selective logging operations on a clay-rich Ferralsol under both dry and wet soil conditions. Distinct ruts formed up to 25 cm depth only under wet conditions. After nine passes the initially very low surface bulk density of between 0.69 and 0.80 g cm(-3) increased to 1.05 g cm(-3) in the wet soil and 0.92 g cm(-3) in the dry soil. Saturated hydraulic conductivities, initially > 250 mm h(-1), declined to a minimum of around 10 mm h(-1) in the wet soil after the first pass, and in the dry soil more gradually after nine passes. The contrasting response of bulk density and saturated hydraulic conductivity is explained by exposure of subsoil material at the base of the ruts where macrostructure rapidly deteriorated under wet conditions. We attribute the resultant moderately high hydraulic conductivities to the formation of stable microaggregates with fine sand to coarse silt textures. We conclude that the topsoil macrostructure of Ferralsols is subject to similar deterioration to that of Luvisols in temperate zones. The stable microstructure prevents marked compaction and decrease in hydraulic conductivity under wetter and more plastic soil conditions. However...

Variabilidade entre materiais genéticos de eucalyptus spp quanto à distribuição de raízes finas em latossolos profundos

Pinheiro, Rafael Costa
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Dissertação de Mestrado Formato: xii, 81 f. : il. color. , grafs., tabs
POR
Relevância na Pesquisa
16.74%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Pós-graduação em Ciência Florestal - FCA; Root behavior in deep soil layers is a subject poorly known for tree species. This topic can be important for breeding programs because a fast displacement of the root front is likely to explain different survival rates among clones in deep Ferralsols during exceptional drought periods. Although an inter-clonal variability in root development might account for different strategies to take up large amounts of water stored in deep soil layers after clearcutting, fine root distributions below a depth of 1 m have been poorly investigated for eucalypt clones. The objectives of our study were: a) to assess the inter-clonal variability among different Eucalyptus genetic materials in fine root densities down to the root front in 2 and 4-years-old clonal tests and in soils with different textures; b) to assess if the ratio between leaf area index (LAI) and root area index (RAI) was similar for different Eucalyptus genetic materials; and c) to assess if the relationship between mean stand height and maximum fine roots depth, as already found for a single E. grandis progeny, is similar for all genetic materials. Soils were sampled using a cylindrical auger at several distances from trees...

Sampling and TDR probe insertion in the determination of the volumetric soil water content

Teixeira,W. G.; Schroth,G.; Marques,J. D.; Huwe,Bernd
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2003 EN
Relevância na Pesquisa
16.74%
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 obtained epsilon values, theta was estimated using empirical equations (thetaTDR), and compared with thetaGrav derived from disturbed and undisturbed samples. The main objective of this study was the comparison of thetaTDR estimates of horizontally as well as vertically inserted probes with the thetaGrav values determined by disturbed and undisturbed samples. Results showed that thetaTDR estimates of vertically inserted probes and the average of horizontally measured layers were only slightly and insignificantly different. However...

Soil organic matter and fertility of anthropogenic dark earths (Terra Preta de Índio) in the Brazilian Amazon basin

Cunha,Tony Jarbas Ferreira; Madari,Beata Emoke; Canellas,Luciano Pasqualoto; Ribeiro,Lucedino Paixão; Benites,Vinicius de Melo; Santos,Gabriel de Araújo
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2009 EN
Relevância na Pesquisa
17.94%
Fertility properties, total C (Ctot), and chemical soil organic matter fractions (fulvic acid fraction - FA, humic acid fraction - HA, humin fraction - H) of anthropogenic dark earths (Terra Preta de Índio) of the Amazon basin were compared with those of Ferralsols with no anthropogenic A horizon. Terra Preta soils had a higher fertility (pH: 5.1-5.4; Sum of bases, SB: 8.93-10.33 cmol c kg-1 , CEC: 17.2-17.5 cmol c kg-1 , V: 51-59 %, P: 116-291 mg kg-1) and Ctot (44.6-44.7 g kg-1) than adjacent Ferralsols (pH: 4.4; SB: 2.04 cmol c kg-1, CEC: 9.5 cmol c kg-1, V: 21 %, P 5 mg kg-1, C: 37.9 g kg-1). The C distribution among humic substance fractions (FA, HA, H) in Terra Preta soils was also different, as shown by the ratios HA:FA and EA/H (EA=HA+FA) (2.1-3.0 and 1.06-1.08 for Terra Preta and 1.2 and 0.72 for Ferralsols, respectively). While the cation exchange capacity (CEC), of Ferralsols correlated with FA (r = 0.97), the CEC of Terra Preta correlated with H (r = 0.82). The correlation of the fertility of Terra Preta with the highly stable soil organic matter fraction (H) is highly significant for the development of sustainable soil fertility management models in tropical ecosystems.

Soil structure transformations from ferralic to nitic horizons on a toposequence in southeastern Brazil

Cooper,Miguel; Vidal-Torrado,Pablo; Grimaldi,Michel
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2010 EN
Relevância na Pesquisa
16.74%
The soil structure transformation from ferralic to nitic horizons was studied in a toposequence on quaternary red clayey sediments and diabase in Piracicaba (SP), Brazil. Morphological and micromorphological studies, image analysis, soil water characteristic curves and monitoring of (total) soil water potential head were used. The presence of polyconcave vughs, clayskins and planar voids shows that the vertical and lateral transition and structural transformation from ferralic to nitic horizons is given by the coalescence of the microaggregates, probably due to tensions created in a drier period in the past. Changes to a more humid climate with a defined dry season and alternate drying and wetting cycles resulted in the fissuration of the previously coalesced material, forming polyhedral aggregates and microaggregates. Simultaneously, clay illuviation filled the voids and together with the compacting action of the biological activity of these soils contributed to the coalescence of microaggregates.

Relationship between soil oxidizable carbon and physical, chemical and mineralogical properties of umbric ferralsols

Marques,Flávio Adriano; Calegari,Márcia Regina; Vidal-Torrado,Pablo; Buurman,Peter
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2011 EN
Relevância na Pesquisa
38.09%
The occurrence of Umbric Ferralsols with thick umbric epipedons (> 100 cm thickness) in humid Tropical and Subtropical areas is a paradox since the processes of organic matter decomposition in these environments are very efficient. Nevertheless, this soil type has been reported in areas in the Southeast and South of Brazil, and at some places in the Northeast. Aspects of the genesis and paleoenvironmental significance of these Ferralsols still need a better understanding. The processes that made the umbric horizons so thick and dark and contributed to the preservation of organic carbon (OC) at considerable depths in these soils are of special interest. In this study, eight Ferralsols with a thick umbric horizon (UF) under different vegetation types were sampled (tropical rain forest, tropical seasonal forest and savanna woodland) and their macromorphological, physical, chemical and mineralogical properties studied to detect soil characteristics that could explain the preservation of high carbon amounts at considerable depths. The studied UF are clayey to very clayey, strongly acidic, dystrophic, and Al-saturated and charcoal fragments are often scattered in the soil matrix. Kaolinites are the main clay minerals in the A and B horizons...

Study of flow in vadose zone from electrical resistivity surveys

Morais,Fernando de; Bacellar,Luis de Almeida Prado; Aranha,Paulo Roberto Antunes
Fonte: Sociedade Brasileira de Geofísica Publicador: Sociedade Brasileira de Geofísica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2008 EN
Relevância na Pesquisa
16.74%
Among the indirect methods applied to environmental monitoring, electrical resistivity has played an important role in accessing water flow in the non-saturated zone of the soil and, consequently, aquifer recharge. This work evaluates the influence of some pedo-geomorphologic properties in the infiltration and percolation of water through the superficial soil horizons by means of multitemporal electrical resistivity sections. The experiments were carried out in two areas of distinct pedo-geomorphological characteristics developed on the crystalline basement of southeastern Brazil. The first is situated in a hollow -shaped slope where lixisols predominate; the second, in a nose -shaped slope where well-developed soils (ferralsols ) predominate. The results proved the efficiency of the electrical resistivity method to delimit percolation of tropical soils, even when subtle differences are found in the hydraulic properties of the soil. It was also possible to establish that in the nose slope percolation is faster than in the hollow.

Use of Fe3+ ion probe to study intensively weathered soils utilizing electron paramagnetic resonance and optical spectroscopy

Balena,S. P; Messerschmidt,I; Tomazoni,J. C; Guimarães,E; Pereira,B. F; Ponzoni,F. J; Blum,W. E. H; Mangrich,A. S
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2011 EN
Relevância na Pesquisa
16.74%
Electron paramagnetic resonance (EPR) spectroscopy and optical analyses of intensively weathered soils containing high levels of oxide-hydroxide of iron from a pilot project on precision agriculture, including 13 farms in the southwest of Paraná state, Brazil, were carried out, aiming at defining parameters of soil fertility. The results of the optical studies in the laboratory were compared with those obtained by the use of a portable spectroradiometer in field conditions. The studied soils were mainly composed of 1:1 clay minerals, oxides and oxide hydroxides of iron (mainly goethite and hematite) and aluminum (mainly gibbsite), characteristics of highly weathered soils, as for example Ferralsols. The EPR spectra, typical of mutual magnetic interaction of aggregated Fe3+ ions, showed a signal linewidth increase at g ca. 2 upon cooling. This phenomenon can be caused by changing the crystal field environment of Fe3+ ions or by the spin-spin relaxation mechanism, which causes an increase of linewith when the temperature decreases. The optical spectral curves obtained from the portable spectroradiometer presented less detailed but more specific features for each soil sample analyzed. The results indicate that use of the portable spectroradiometer along with mathematical tools such as the second derivative mode of the Kubelka-Munk function is a good alternative to analyze clay soils rich in metallic oxide and oxide hydroxides. A full attribution of the spectra features was made...

Software Image J to study soil pore distribution

Passoni,Sabrina; Borges,Fernando da Silva; Pires,Luiz Fernando; Saab,Sérgio da Costa; Cooper,Miguel
Fonte: Editora da Universidade Federal de Lavras Publicador: Editora da Universidade Federal de Lavras
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2014 EN
Relevância na Pesquisa
16.74%
In the soil science, a direct method that allows the study of soil pore distribution is the bi-dimensional (2D) digital image analysis. Such technique provides quantitative results of soil pore shape, number and size. The use of specific softwares for the treatment and processing of images allows a fast and efficient method to quantify the soil porous system. However, due to the high cost of commercial softwares, public ones can be an interesting alternative for soil structure analysis. The objective of this work was to evaluate the quality of data provided by the Image J software (public domain) used to characterize the voids of two soils, characterized as Geric Ferralsol and Rhodic Ferralsol, from the southeast region of Brazil. The pore distribution analysis technique from impregnated soil blocks was utilized for this purpose. The 2D image acquisition was carried out by using a CCD camera coupled to a conventional optical microscope. After acquisition and treatment of images, they were processed and analyzed by the software Noesis Visilog 5.4® (chosen as the reference program) and ImageJ. The parameters chosen to characterize the soil voids were: shape, number and pore size distribution. For both soils, the results obtained for the image total porosity (%)...

Methanotrophic Communities in Brazilian Ferralsols from Naturally Forested, Afforested, and Agricultural Sites▿ †

Dörr, Nicole; Glaser, Bruno; Kolb, Steffen
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.39%
Conversion of forests to farmland permanently lowers atmospheric methane consumption due to unresolved reasons. Alphaproteobacterial methanotrophs were predominant in forested soils and gammaproteobacterial species were predominant in farmland soils of subtropical ferralsols in Brazil. The capability of atmospheric methane consumption was obliterated in farmland soils, suggesting a shift from oligotrophic to copiotrophic species.

Retenção e mobilidade de cádmio em solos: revisão e estudo de caso em ambiente tropical; Not available.

Deucher, Marta Teresa
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 19/12/2001 PT
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17.73%
Esta dissertação consiste da avaliação do comportamento geoquímico do Cádmio em ambiente tropical. Parte dos dados obtidos provem de investigação bibliográfica na qual comprova-se que em solos, os principais fatores que determinam a retenção e a mobilidade do cádmio são: pH, Eh, granulometria, conteúdos em óxidos e hidróxidos de ferro e alumínio e argilominerais, conteúdos em matéria orgânica, presença de cátions que disputam os mesmos sítios cristaloquímicos e concentração inicial de metal. Com base na literatura consultada, verifica-se serem os elementos determinantes na delimitação da adsorção ou disponibilidade do cádmio em ambiente tropical os seguintes em ordem de importância: 1. A existência de quantidades de hidróxidos de Fe e Al nos solos favorecem a retenção de Cd 2. A presença de matéria orgânica propicia retenção de Cd principalmente face a existência de espessos horizontes A (húmico) em ambientes tropicais 3. Solos com pH ácido induzem a disponibilidade de Cd e pH básico, sua retenção sob formas adsorvidas ou precipitadas 4. A presença de minerais de cálcio propiciam retenção de Cd 5. A fração granulométrica argila conduz a uma maior adsorção de Cd 6. E finalmente...

Effects of Fe oxide on N transformations in subtropical acid soils

Jiang, Xianjun; Xin, Xiaoping; Li, Shiwei; Zhou, Junchao; Zhu, Tongbin; Müller, Christopher; Cai, Zucong; Wright, Alan L.
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em 27/02/2015 EN
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Subtropical ecosystems are often characterized by high N cycling rates, but net nitrification rates are often low in subtropical acid soils. NO3−-N immobilization into organic N may be a contributing factor to understand the observed low net nitrification rates in these acid soils. The effects of Fe oxide and organic matter on soil N transformations were evaluated using a 15N tracing study. Soil net nitrification was low for highly acidic yellow soil (Ferralsols), but gross ammonia oxidation was 7 times higher than net nitrification. In weakly acidic purple soil (Cambisols), net nitrification was 8 times higher than in Ferralsols. The addition of 5% Fe oxide to Cambisols, reduced the net nitrification rate to a negative rate, while NO3−-N immobilization rate increased 8 fold. NO3−-N immobilization was also observed in Ferralsols which contained high Fe oxides levels. A possible mechanism for these reactions could be stimulation of NO3−-N immobilization by Fe oxide which promoted the abiotic formation of nitrogenous polymers, suggesting that the absence of net nitrification in some highly acid soils may be due to high rates of NO3−-N immobilization caused by high Fe oxide content rather than a low pH.

LANDSCAPE ATRIBUTES DERIVED FROM DIGITAL ELEVATION MODEL AND RELATIONSHIPS WITH SOILS; ATRIBUTOS DO RELEVO DERIVADOS DE MODELO DIGITAL DE ELEVAÇÃO E SUAS RELAÇÕES COM SOLOS

SIRTOLI, Angelo Evaristo; UFPR; SILVEIRA, Claudinei Taborda da; UFPR; MANTOVANI, Luiz Eduardo; UFPR; SIRTOLI, Ana Rosa dos Anjos; UERGS; OKA-FIORI, Chisato; UFPR
Fonte: UFPR Publicador: UFPR
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf
Publicado em 24/06/2008 ENG
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The present study approaches the relationships between soils and attributes of the landscape derived from a digital elevation model (DEM) in a area over the Guabirotuba Formation formed by alluvial and secondary deposits colluvial fans deposits. Starting from the digital elevation model we did derived six primary landscape attributes: elevation, slope, global solar radiation, plan and profile curvature. A secondary attribute, the topographical index of humidity (TIW) was also created. The eventual interactions between the geology and the derived attributes of DEM with the soil mapped in the area were evaluated. The results showed that combination of the geology and TWI data can explain occurrence of Gleyssols and Histosols. The major soils formations were located in the following conditions: Ferralsols - plan landscape with curvature plan and profile, divergent and convex; Cambisols - convergent/divergent and concave; and the association Gleysols and Histosols convergent/planar and flat. The high degree slopes facing south presented matiz betwen 7,5 YR - 10 YR, yellowish soil color. The Ferralsols class and soils with hydromorphic character were located in flat landscape while Cambisols were situated in the largest steepness. The highest positions which represented well preserved soil again loss...