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Espectroscopias de infravermelho próximo e médio na quantificação de atributos do solo, com ênfase na matéria orgânica e na biomassa microbiana; Near and mid-infrared spectroscopy for quantification of soil atributes, focusing organic matter and microbial biomassl

Ferraresi, Tatiana Maris
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 21/05/2010 PT
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A matéria orgânica e a biomassa microbiana do solo consistem em sensíveis indicadores de qualidade do solo e de seus estoques de carbono e nitrogênio que, juntamente com a textura, têm auxiliado na escolha de formas de manejo agronômico mais sustentáveis. Os métodos disponíveis para a determinação da matéria orgânica (Walkley-Black modificado da EMBRAPA SOLOS, 1997) e da biomassa microbiana (Vance et al., 1987a) têm sido largamente utilizados, porém possuem alguns inconvenientes como a geração de resíduos altamente tóxicos e a grande demanda de tempo para analisar um pequeno número de amostras. A espectroscopia, por sua vez, tem se mostrado uma alternativa mais rápida e limpa para a identificação e quantificação de compostos orgânicos. Por esse motivo, este trabalho teve como objetivo testar métodos espectroscópicos, tanto no infravermelho próximo (NIRS) quanto no médio com refletância difusa (DRIFTS), com o uso de calibração multivariada, para a quantificação destes indicadores. Os teores de argila, silte, areia, carbono orgânico total e carbono microbiano, assim como o quociente microbiano (CMIC/COT), foram espectrometricamente preditos de modo satisfatório. Em geral, obtiveram-se melhores resultados utilizando DRIFTS.; Organic matter and microbial biomass are sensible ways to indicate soil quality as well as carbon and nitrogen stocks. These properties...

Biomassa microbiana do solo em sistema de integração lavoura-pecuária em plantio direto, submetido a intensidades de pastejo; Soil microbial biomass in a no-tillage integrated crop-livestock system under different grazing intensities

Souza, Edicarlos Damacena de; Costa, Sérgio Ely Valadão Gigante de Andrade; Anghinoni, Ibanor; Lima, Christina Venzke Simões de; Carvalho, Paulo Cesar de Faccio; Martins, Amanda Posselt
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
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Em sistemas de integração lavoura-pecuária, boa parte do suprimento de nutrientes para as pastagens provém das excreções dos animais, na forma de esterco e de urina, o que resulta em estímulo à atividade e ao acúmulo de nutrientes nas suas células. Este estudo foi desenvolvido num experimento de integração lavourapecuária em plantio direto, iniciado em 2001, e objetivou avaliar o impacto de diferentes intensidades de pastejo da pastagem de inverno (aveia-preta + azevém; 10, 20 e 40 cm, e um tratamento sem pastejo) sobre a atividade microbiana e sobre os teores e estoques de C, N e P na biomassa microbiana na camada de 0–10 cm de um Latossolo Vermelho, no Sul do Brasil, durante o ciclo da pastagem. Os teores e estoques dos nutrientes na biomassa e a atividade microbiana foram alterados pela intensidade de pastejo e pela época no ciclo da pastagem. Os teores de C e de P microbiano aumentaram do início da pastagem, em maio, até o período de grande produção de fitomassa, em setembro, após o qual decresceram, acompanhando o início de senescência da pastagem. Por sua vez, o N microbiano decresceu de maio para novembro, possivelmente devido à absorção desse nutriente pelas plantas. Sistemas de integração lavoura-pecuária em plantio direto mantêm a qualidade biológica do solo...

Alterações na matéria orgânica e na biomassa microbiana em solo de mata natural submetido a diferentes manejos

MARCHIORI JÚNIOR, MILTON; MELO, WANDERLEY JOSÉ DE
Fonte: Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) Publicador: Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA)
Tipo: Artigo de Revista Científica Formato: 1177-1182
POR
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Avaliou-se, em um Latossolo Roxo, o efeito de diferentes formas de manejo do solo sobre a matéria orgânica do solo e na biomassa microbiana. Os tratamentos usados foram: mata natural; mata natural até 1976 e café até 1994 (amostragem na projeção da copa e na entrelinha); mata natural até 1976, café até 1991 e milho até 1994; mata natural até 1940, café até 1960, citros até 1978, e cana-de-açúcar até 1994 (amostragem na linha e na entrelinha). A mata natural apresentou os maiores valores de C orgânico no solo e na fração humina e os menores valores foram obtidos nas áreas com cana-de-açúcar, que apresentaram os maiores valores de C microbiano em relação à mata natural. O uso agrícola do solo aumentou a porcentagem de C orgânico na forma de ácidos húmicos e fúlvicos, em relação à mata natural. em geral, o solo apresentou mais de 74% do C orgânico na forma de húmus residual.; The effect of soil management on forms of carbon and microbial biomass was studied in a Typic Euthortox soil. The treatments tested were: natural forest; natural forest till 1976 and coffee till 1994 (sampling on the shoot projection and between lines ); natural forest till 1976...

Industrial and urban organic wastes increase soil microbial activity and biomass

Boechat,Cácio Luiz; Santos,Jorge Antonio Gonzaga; Accioly,Adriana Maria de Aguiar; Bomfim,Marcela Rebouças; Santos,Adailton Conceição dos
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/2012 EN
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Microbial processes have been used as indicators of soil quality, due to the high sensitivity to small changes in management to evaluate, e.g., the impact of applying organic residues to the soil. In an experiment in a completely randomized factorial design 6 x 13 + 4, (pot without soil and residue or absolute control) the effect of following organic wastes was evaluated: pulp mill sludge, petrochemical complex sludge, municipal sewage sludge, dairy factory sewage sludge, waste from pulp industry and control (soil without organic waste) after 2, 4, 6, 12, 14, 20, 28, 36, 44, 60, 74, 86, and 98 days of incubation on some soil microbial properties, with four replications. The soil microbial activity was highly sensitive to the carbon/nitrogen ratio of the organic wastes. The amount of mineralized carbon was proportional to the quantity of soil-applied carbon. The average carbon dioxide emanating from the soil with pulp mill sludge, corresponding to soil basal respiration, was 0.141 mg C-CO2 100 g-1 soil h-1. This value is 6.4 times higher than in the control, resulting in a significant increase in the metabolic quotient from 0.005 in the control to 0.025 mg C-CO2 g-1 Cmic h-1 in the soil with pulp mill sludge. The metabolic quotient in the other treatments did not differ from the control (p < 0.01)...

MICROBIAL CHARACTERISTICS OF SOILS UNDER AN INTEGRATED CROP-LIVESTOCK SYSTEM

Silva,Andréa Scaramal da; Colozzi Filho,Arnaldo; Nakatani,André Shigueyoshi; Alves,Sérgio José; Andrade,Diva de Souza; Guimarães,Maria de Fátima
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2015 EN
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Integrated crop-livestock systems (ICLs) are a viable strategy for the recovery and maintenance of soil characteristics. In the present study, an ICL experiment was conducted by the Instituto Agronômico do Paraná in the municipality of Xambre, Parana (PR), Brazil, to evaluate the effects of various grazing intensities. The objective of the present study was to quantify the levels of microbial biomass carbon (MBC) and soil enzymatic activity in an ICL of soybean (summer) and Brachiaria ruziziensis (winter), with B. ruziziensis subjected to various grazing intensities. Treatments consisted of varying pasture heights and grazing intensities (GI): 10, 20, 30, and 40 cm (GI-10, GI-20, GI-30, and GI-40, respectively) and a no grazing (NG) control. The microbial characteristics analysed were MBC, microbial respiration (MR), metabolic quotient (qCO2), the activities of acid phosphatase, β-glucosidase, arylsuphatase, and cellulase, and fluorescein diacetate (FDA) hydrolysis. Following the second grazing cycle, the GI-20 treatment (20-cm - moderate) grazing intensity) contained the highest MBC concentrations and lowest qCO2 concentrations. Following the second soybean cycle, the treatment with the highest grazing intensity (GI-10) contained the lowest MBC concentration. Soil MBC concentrations in the pasture were favoured by the introduction of animals to the system. High grazing intensity (10-cm pasture height) during the pasture cycle may cause a decrease in soil MBC and have a negative effect on the microbial biomass during the succeeding crop. Of all the enzymes analyzed...

Microbial enzymatic activity and thermal effect in a tropical soil treated with organic materials

Cenciani,Karina; Freitas,Sueli dos Santos; Critter,Silvana Auxiliadora Missola; Airoldi,Cláudio
Fonte: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz" Publicador: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2008 EN
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Bacteria and fungi are the most active decomposers of organic materials in soil. They directly affect plant nutrient availability, and chemical and physical properties of soils. This investigation aimed at quantifying the effect of several organic materials on microbial activity of a Rhodic Eutrudox. Soil samples were incubated over a period of 91 days with the following organic materials: cattle manure (CM), earthworm humus (HM), and city sewage sludge from Barueri (BA) and Franca (FR). The activities of cellulase, protease and urease enzymes, the soil microbial carbon content (by fumigation-extraction method) and the exothermal effect were evaluated. Experimental design was randomized and arranged as factorial scheme five treatments x seven samplings with five replications. Organic materials promoted oscillations in microbial carbon (mg C g-1 soil), and enzyme activities - cellulase (µg glucose g-1 soil 24 h-1), protease (mg Tyr g-1 soil 2 h-1), urease (mg NH4+-N g-1 soil 2 h-1) - and the total thermal effect (J g-1 soil), in the following decreasing order: (1) CM - 21.47; 655.90; 49.68; 24.55; 477.90; (2) BA - 12.98; 367.70; 32.76; 10.66; 426.29; (3) FR - 11.60; 273.40; 18.77; 19.35; 368.00; (4) HM - 11.77; 261.00; 17.05; 9.02; 202.79; (5) control. Correlations were obtained between microbial carbon and cellulase and protease activities (r = 0.54; p < 0.001)...

Soil microbial biomass under mulch types in an integrated apple orchard from Southern Brazil

Almeida,Denice de Oliveira; Klauberg Filho,Osmar; Almeida,Henrique Cesar; Gebler,Luciano; Felipe,Aline Franciane
Fonte: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz" Publicador: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2011 EN
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The use of mulching is an alternative to control weeds but there are few studies on its effect on soil quality. In this sense, this study aimed to evaluate the effect of types of mulching on the attributes of microbial carbon, nitrogen and phosphorus in a Typic Hapludox with production of integrated apples in southern Brazil. The experiment was conducted in randomized blocks in the Vacaria, state of Rio Grande do Sul, southern Brazil. The soil mulch types studied were: pine needle, sawdust, black plastic and a control. The soil samples were collected in February (summer) and August (winter) of 2006, and the attributes related to total organic and microbial carbon, nitrogen and phosphorus were determined. Organic mulchings (pine needle and sawdust) promoted lower soil temperature, and greater moisture, microbial carbon (Cmic), microbial nitrogen (Nmic), and the ratios Cmic:Corg, Nmic:Norg and microbial C:N than black plastic. Microbial phosphorus was greater in winter. Sawdust mulching promoted the best conditions to microbial biomass in winter. The mulch types increased the microbial compartment in winter as compared to the nonweeded control .

Soil biochemistry and microbial activity in vineyards under conventional and organic management at Northeast Brazil

Freitas,Nicácio de Oliveira; Yano-Melo,Adriana Mayumi; Silva,Fábio Sérgio Barbosa da; Melo,Natoniel Franklin de; Maia,Leonor Costa
Fonte: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz" Publicador: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2011 EN
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The São Francisco Submedium Valley is located at the Brazilian semiarid region and is an important center for irrigated fruit growing. This region is responsible for 97% of the national exportation of table grapes, including seedless grapes. Based on the fact that organic fertilization can improve soil quality, we compared the effects of conventional and organic soil management on microbial activity and mycorrhization of seedless grape crops. We measured glomerospores number, most probable number (MPN) of propagules, richness of arbuscular mycorrhizal fungi (AMF) species, AMF root colonization, EE-BRSP production, carbon microbial biomass (C-MB), microbial respiration, fluorescein diacetate hydrolytic activity (FDA) and metabolic coefficient (qCO2). The organic management led to an increase in all variables with the exception of EE-BRSP and qCO2. Mycorrhizal colonization increased from 4.7% in conventional crops to 15.9% in organic crops. Spore number ranged from 4.1 to 12.4 per 50 g-1 soil in both management systems. The most probable number of AMF propagules increased from 79 cm-3 soil in the conventional system to 110 cm-3 soil in the organic system. Microbial carbon, CO2 emission, and FDA activity were increased by 100 to 200% in the organic crop. Thirteen species of AMF were identified...

Microbial soil quality indicators under different crop rotations and tillage management

Ferreira,Enderson Petrônio de Brito; Santos,Henrique Pereira dos; Costa,Janaina Ribeiro; De-Polli,Helvécio; Rumjanek,Norma Gouvêa
Fonte: Universidade Federal do Ceará Publicador: Universidade Federal do Ceará
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2010 EN
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An experiment was carried out under field conditions to assess the effects of soil management (no-tillage- NT and conventional tillage- CT) and crop rotation systems on microbial biomass-C (Cmic), basal soil respiration (BSR), metabolic quotient (qCO2), soil organic carbon content (Corg) and microbial carbon to organic carbon ratio (Cmic/Corg). Soil samples were collected on an area cultivated with wheat as winter crop and soybean as summer crop, both in rotation with vetch, maize and oats. Samples were also collected in a secondary forest used as reference. Data of each management system (NT and CT) were compared to forest area by "t" test (p<0.05) and crop rotations were compared by Tukey test (p<0.05). All data were submitted to multivariate analysis (Principal Component Analysis - PCA). There were observed significant differences ("t" test; p<0.05) for Cmic, BSR, qCO2 and Cmic/Corg between NT and CT, by which NT values resemble those for forest area. For crop rotations significant differences (Tukey test; p<0.05) were found only for BSR and qCO2. The sum of the two first principal components on the PCA explained about 75% of the data variation. PCA showed NT closest to forest area than CT, especially treatments with soybean and vetch as consecutive crops. The forest area-NT clustering was mostly due to Cmic and Cmic/Corg relationship. Results indicate that the NT system is more sustainable than the CT system and can contribute for the accumulation a greater quantity of carbon in soil.

Benthic Bacterial and Fungal Productivity and Carbon Turnover in a Freshwater Marsh

Buesing, Nanna; Gessner, Mark O.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /01/2006 EN
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Heterotrophic bacteria and fungi are widely recognized as crucial mediators of carbon, nutrient, and energy flow in ecosystems, yet information on their total annual production in benthic habitats is lacking. To assess the significance of annual microbial production in a structurally complex system, we measured production rates of bacteria and fungi over an annual cycle in four aerobic habitats of a littoral freshwater marsh. Production rates of fungi in plant litter were substantial (0.2 to 2.4 mg C g−1 C) but were clearly outweighed by those of bacteria (2.6 to 18.8 mg C g−1 C) throughout the year. This indicates that bacteria represent the most actively growing microorganisms on marsh plant litter in submerged conditions, a finding that contrasts strikingly with results from both standing dead shoots of marsh plants and submerged plant litter decaying in streams. Concomitant measurements of microbial respiration (1.5 to 15.3 mg C-CO2 g−1 of plant litter C day−1) point to high microbial growth efficiencies on the plant litter, averaging 45.5%. The submerged plant litter layer together with the thin aerobic sediment layer underneath (average depth of 5 mm) contributed the bulk of microbial production per square meter of marsh surface (99%)...

Formation of Polyhydroxyalkanoate in Aerobic Anoxygenic Phototrophic Bacteria and Its Relationship to Carbon Source and Light Availability▿

Xiao, Na; Jiao, Nianzhi
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /11/2011 EN
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Aerobic anoxygenic phototrophic bacteria (AAPB) are unique players in carbon cycling in the ocean. Cellular carbon storage is an important mechanism regulating the nutrition status of AAPB but is not yet well understood. In this paper, six AAPB species (Dinoroseobacter sp. JL1447, Roseobacter denitrificans OCh 114, Roseobacter litoralis OCh 149, Dinoroseobacter shibae DFL 12T, Labrenzia alexandrii DFL 11T, and Erythrobacter longus DSMZ 6997) were examined, and all of them demonstrated the ability to form the carbon polymer polyhydroxyalkanoate (PHA) in the cell. The PHA in Dinoroseobacter sp. JL1447 was identified as poly-beta-hydroxybutyrate (PHB) according to evidence from Fourier transform infrared spectroscopy, differential scanning calorimetry, and 1H nuclear magnetic resonance spectroscopy examinations. Carbon sources turned out to be critical for PHA production in AAPB. Among the eight media tested with Dinoroseobacter sp. JL1447, sodium acetate, giving a PHA production rate of 72%, was the most productive carbon source, followed by glucose, with a 68% PHA production rate. Such PHA production rates are among the highest recorded for all bacteria. The C/N ratio of substrates was verified by the experiments as another key factor in PHA production. In the case of R. denitrificans OCh 114...

Abundance and Distribution of Synechococcus spp. and Cyanophages in the Chesapeake Bay▿†

Wang, Kui; Wommack, K. Eric; Chen, Feng
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /11/2011 EN
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Despite the increasing knowledge of Synechococcus spp. and their co-occurring cyanophages in oceanic and coastal water, little is known about their abundance, distribution, and interactions in the Chesapeake Bay estuarine ecosystem. A 5-year interannual survey shows that Synechococcus spp. and their phages are persistent and abundant members of Chesapeake Bay microbial communities. Synechococcus blooms (106 cells ml−1) were often observed in summer throughout the Bay, contributing 20 to 40% of total phytoplankton chlorophyll a. The distribution of phycoerythrin-containing (PE-rich) Synechococcus cells appeared to mostly correlate with the salinity gradient, with higher abundances at higher salinities. Cyanophages infectious to Synechococcus were also abundant (up to 6 × 105 viruses ml−1 by the most probable number assay) during summer months in the Bay. The covariation in abundance of Synechococcus spp. and cyanophages was evident, although the latitude of observed positive correlation varied in different years, mirroring the changing environmental conditions and therefore the host-virus interactions. The impacts of cyanophages on host Synechococcus populations also varied spatially and temporally. Higher phage-related Synechococcus mortality was observed in drought years. Virus-mediated host mortality and subsequent liberation of dissolved organic matter (DOM) may substantially influence oceanic biogeochemical processing through the microbial loop as well as the microbial carbon pump. These observations emphasize the influence of environmental gradients on natural Synechococcus spp. and their phage population dynamics in the estuarine ecosystem.

The Microbial Carbon Pump: from Genes to Ecosystems▿

Jiao, Nianzhi; Zheng, Qiang
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /11/2011 EN
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The majority of marine dissolved organic carbon (DOC) is resistant to biological degradation and thus can remain in the water column for thousands of years, constituting carbon sequestration in the ocean. To date the origin of such recalcitrant DOC (RDOC) is unclear. A recently proposed conceptual framework, the microbial carbon pump (MCP), emphasizes the microbial transformation of organic carbon from labile to recalcitrant states. The MCP is concerned with both microbial uptakes and outputs of DOC compounds, covering a wide range from gene to ecosystem levels. In this minireview, the ATP binding cassette (ABC) transporter is used as an example for the microbial processing of DOC at the genetic level. The compositions of the ABC transporter genes of the two major marine bacterial clades Roseobacter and SAR11 demonstrate that they have distinct patterns in DOC utilization: Roseobacter strains have the advantage of taking up carbohydrate DOC, while SAR11 bacteria prefer nitrogen-containing DOC. At the ecosystem level, bacterially derived RDOC based on d-amino acid biomarkers is reported to be responsible for about a quarter of the total marine RDOC pool. Under future global warming scenarios, partitioning of primary production into DOC could be enhanced...

Bioensaios com fósforo e indicadores químicos, microbianos e bioquímicos do solo, em áreas sob cerrado, pinus e plantio direto; Phosphorus bioassays and chemical, microbial and biochemical indicators of soil in areas under savannah, pinus forest and no-tillage

Vinhal-Freitas, Isabel Cristina
Fonte: Universidade Federal de Uberlândia Publicador: Universidade Federal de Uberlândia
Tipo: Dissertação
POR
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A atividade microbiana no solo exerce grande importância na regulação dos processos de transformação de carbono e nutrientes, a exemplo do fósforo. No entanto, a atividade da microbiota é fortemente ligada a práticas agrícolas de uso do solo. No capítulo I, o trabalho teve como objetivo comparar três sistemas de uso do solo, em relação à resposta da atividade microbiana e metabólica, quando da adição de fósforo e glicose em Latossolo fase cerrado. Os sistemas de uso do solo foram: área de cerrado (CE), floresta de pinus com árvores de 32 anos (FP) e plantio direto (PD) com 11 anos. As amostras de solos foram coletadas na profundidade de 0-10 cm, nos meses de janeiro, junho e dezembro de 2008, e foram avaliadas quanto ao carbono liberado (C-CO2) pela atividade microbiana; carbono orgânico total (COT); carbono da biomassa microbiana (CBM); glicose total (GT) e rendimento metabólico. A adição de doses crescentes de P aumentou a atividade respiratória dos solos dos três sistemas de uso. A adição de P aumentou a atividade microbiana (atividade respiratória, com incremento em biomassa microbiana) e rendimento metabólico (eficiência de utilização da glicose), principalmente se adicionado junto com uma fonte de carbono (glicose). O uso de testes de incubação do solo com adição de nutrientes pode ser usado para caracterizar o potencial de resposta metabólica de solos com características de uso diferentes...

Investigating the Use of Microbe-Related d13C and d15N Signatures to Detect Uranium Mineralization at Depth

Cadeau, Tara
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN
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Secondary far-field attributes of ore deposits are becoming critically important in exploration where primary aspects of the deposit may be concealed. These are geochemical, biological, and mineralogical characteristics of ore deposits, such as a reduced column or trace-element dendrochemistry, formed by interactions between a deposit and the hydrosphere or biosphere. The purpose of this study is to investigate the value of microbe-related δ13C & δ15N signatures as a secondary far-field attribute for detecting uranium mineralization at depth. It is modelled after an earlier, similar (unpublished) report on the Cigar Lake unconformity-related uranium deposit in the Athabasca basin. At Cigar Lake, chemical and visual evidence of microbes was found in fractures and background core samples and was correlated with pathfinder elements, demonstrating that microbial C and N isotopic compositions could be traced along pathfinder element migration pathways toward the deposit. This study investigates the nature and distribution of isotopic signatures on fracture surfaces from seven drill-cores obtained from the Outer-Ring and Matheson properties, a prospective site of uranium mineralization in the Eastern Athabasca Basin 45km northwest of the Cigar Lake deposit. The fracture-surface and non-fractured samples (41 of each) were analyzed using an elemental analyzer-isotope ratio mass spectrometer (EA-IRMS) to get total C and N content and δ13C & δ15N values...

EFFECT OF WATER AVAILABILITY ON SOIL MICROBIAL BIOMASS IN SECONDARY FOREST IN EASTERN AMAZONIA

Rangel-Vasconcelos,Lívia Gabrig Turbay; Zarin,Daniel Jacob; Oliveira,Francisco de Assis; Vasconcelos,Steel Silva; Carvalho,Cláudio José Reis de; Santos,Maria Marly de Lourdes Silva
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2015 EN
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Soil microbial biomass (SMB) plays an important role in nutrient cycling in agroecosystems, and is limited by several factors, such as soil water availability. This study assessed the effects of soil water availability on microbial biomass and its variation over time in the Latossolo Amarelo concrecionário of a secondary forest in eastern Amazonia. The fumigation-extraction method was used to estimate the soil microbial biomass carbon and nitrogen content (SMBC and SMBN). An adaptation of the fumigation-incubation method was used to determine basal respiration (CO2-SMB). The metabolic quotient (qCO2) and ratio of microbial carbon:organic carbon (CMIC:CORG) were calculated based on those results. Soil moisture was generally significantly lower during the dry season and in the control plots. Irrigation raised soil moisture to levels close to those observed during the rainy season, but had no significant effect on SMB. The variables did not vary on a seasonal basis, except for the microbial C/N ratio that suggested the occurrence of seasonal shifts in the structure of the microbial community.

Microbial carbon within and above exotic copper deposits in northern Chile : implications for ore genesis and exploration

Nelson, Mark Alan
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado Formato: 2969032 bytes; application/pdf
EN; EN
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“Exotic-type” Cu silicate-oxide deposits hosted by Miocene pediment gravels represent an unusual, but characteristic, by-product of the supergene enrichment of Cenozoic porphyry Cu deposits in northern Chile. Carbon stable isotopic analysis is employed herein to clarify the environment of exotic ore formation and to provide guidelines for the exploration for non-outcropping mineralisation. Two main sample suites were examined: chrysocolla-rich ores from the Huinquintipa and Mina Sur deposits; and soils overlying a paleochannel in the Huinquintipa area known to be mineralised. The samples were processed using four different analytical techniques to determine their 13C values: (1) Elemental Analysis Isotope Ratio Mass Spectrometry (EA/IRMS) of the whole sample; (2) crushing in vacuo followed by IRMS to analyse fluid inclusions; (3) thermal extraction at 100˚C, followed by IRMS to analyse weakly bound carbon dioxide; and (4) ethylenediaminetetraacetic acid (EDTA) extraction followed by IRMS. EDTA-partial extraction favours the dissolution of minerals with divalent cations, releasing as carbon dioxide the carbon trapped within the crystal structure. All four of these analytical techniques have been used before, but this is the first time that they have all been used together on exotic copper silicate and oxide mineralisation. Three major carbon sources are identified: (1) atmosphere-derived carbon dioxide with a 13C value of around 0 ‰; (2) plant-derived carbon dioxide with a 13C of about -25 ‰; and (3) microbe-derived carbon dioxide with a 13C of approximately -50 ‰. The bulk of the carbon liberated by EA/IRMS was plant-derived. The thermally- and crushing-released carbon dioxide has the highest proportion of atmosphere-derived carbon...

Microbial enzymatic activity and thermal effect in a tropical soil treated with organic materials; Atividade enzimática da microbiota e efeito térmico em solo tropical tratado com compostos orgânicos

Cenciani, Karina; Freitas, Sueli dos Santos; Critter, Silvana Auxiliadora Missola; Airoldi, Cláudio
Fonte: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz Publicador: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/12/2008 ENG
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480.8408%
Bactérias e fungos são os organismos mais ativos na decomposição de compostos orgânicos no solo, afetando diretamente a disponibilidade de nutrientes para as plantas e as propriedades químicas e físicas dos solos. Este estudo quantificou o efeito de diversos compostos orgânicos na atividade microbiana de um Latossolo Vermelho Eutroférrico típico. As amostras de solo foram incubadas durante 91 dias sob os tratamentos: esterco bovino (CM), húmus de minhoca (HM), e os lodos de esgoto de Barueri (BA) e Franca (FR). Foram avaliadas as atividades das enzimas celulase, protease e urease, o carbono microbiano do solo (método fumigação-extração) e o efeito exotérmico total. O delineamento experimental foi inteiramente casualizado, em esquema fatorial cinco tratamentos x sete amostragens com 5 repetições. Os compostos orgânicos promoveram oscilações no carbono microbiano (mg C g-1 solo), na atividade das enzimas celulase (µg glicose g-1 solo 24 h-1), protease (mg Tyr g-1 solo 2 h-1) e urease (mg NH4+-N g-1 solo 2 h-1) e no efeito térmico total (J g-1 solo), na seguinte ordem decrescente: (1) CM - 21.47; 655.90; 49.68; 24.55; 477.90; (2) BA - 12.98; 367.70; 32.76; 10.66; 426.29; (3) FR - 11.60; 273.40; 18.77; 19.35; 368.00; (4) HM - 11.77; 261.00; 17.05; 9.02; 202.79; (5) controle. Correlações foram obtidas entre o carbono microbiano e as enzimas celulase e protease (r = 0.54; p < 0.001)...

Biomassa microbiana do solo sob coberturas em pomar integrado de maçãs no Sul do Brasil; Soil microbial biomass under mulch types in an integrated apple orchard from Southern Brazil

Almeida, Denice de Oliveira; Klauberg Filho, Osmar; Almeida, Henrique Cesar; Gebler, Luciano; Felipe, Aline Franciane
Fonte: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz Publicador: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/04/2011 ENG
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585.9763%
The use of mulching is an alternative to control weeds but there are few studies on its effect on soil quality. In this sense, this study aimed to evaluate the effect of types of mulching on the attributes of microbial carbon, nitrogen and phosphorus in a Typic Hapludox with production of integrated apples in southern Brazil. The experiment was conducted in randomized blocks in the Vacaria, state of Rio Grande do Sul, southern Brazil. The soil mulch types studied were: pine needle, sawdust, black plastic and a control. The soil samples were collected in February (summer) and August (winter) of 2006, and the attributes related to total organic and microbial carbon, nitrogen and phosphorus were determined. Organic mulchings (pine needle and sawdust) promoted lower soil temperature, and greater moisture, microbial carbon (Cmic), microbial nitrogen (Nmic), and the ratios Cmic:Corg, Nmic:Norg and microbial C:N than black plastic. Microbial phosphorus was greater in winter. Sawdust mulching promoted the best conditions to microbial biomass in winter. The mulch types increased the microbial compartment in winter as compared to the nonweeded control .; O uso da cobertura do solo é alternativa para o controle de plantas daninhas. Entretanto há poucos estudos sobre seu efeito na qualidade do solo. Avaliou-se...

Soil biochemistry and microbial activity in vineyards under conventional and organic management at Northeast Brazil; Atividade bioquímica e microbiológica do solo em videiras sob manejo orgânico e convencional no Nordeste do Brasil

Freitas, Nicácio de Oliveira; Yano-Melo, Adriana Mayumi; Silva, Fábio Sérgio Barbosa da; Melo, Natoniel Franklin de; Maia, Leonor Costa
Fonte: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz Publicador: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/04/2011 ENG
Relevância na Pesquisa
476.388%
The São Francisco Submedium Valley is located at the Brazilian semiarid region and is an important center for irrigated fruit growing. This region is responsible for 97% of the national exportation of table grapes, including seedless grapes. Based on the fact that organic fertilization can improve soil quality, we compared the effects of conventional and organic soil management on microbial activity and mycorrhization of seedless grape crops. We measured glomerospores number, most probable number (MPN) of propagules, richness of arbuscular mycorrhizal fungi (AMF) species, AMF root colonization, EE-BRSP production, carbon microbial biomass (C-MB), microbial respiration, fluorescein diacetate hydrolytic activity (FDA) and metabolic coefficient (qCO2). The organic management led to an increase in all variables with the exception of EE-BRSP and qCO2. Mycorrhizal colonization increased from 4.7% in conventional crops to 15.9% in organic crops. Spore number ranged from 4.1 to 12.4 per 50 g-1 soil in both management systems. The most probable number of AMF propagules increased from 79 cm-3 soil in the conventional system to 110 cm-3 soil in the organic system. Microbial carbon, CO2 emission, and FDA activity were increased by 100 to 200% in the organic crop. Thirteen species of AMF were identified...