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Source rock/dispersed organic matter characterization-TSOP research subcommitee results

Teerman, S. C.; Cardott, B. J.; Harding, R. W.; Lemos de Sousa, M. J.; Logan, D. R.; Pinheiro, H. J.; Reinhardt, M.; Thompson-Rizer, C. L.; Woods, R. A.
Fonte: Pergamon Publicador: Pergamon
Tipo: Artigo de Revista Científica
Publicado em //1995 ENG
Relevância na Pesquisa
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Because sedimentary organic matter consists of a diverse mixture of organic components with different properties, a combination of chemical and petrographic results offers the most complete assessment of source rock properties. The primary purpose of this Society for Organic Petrology (TSOP) subcommittee is to contribute to the standardization of kerogen characterization methods. Specific objectives include: (1) evaluation of the applications of different organic matter (petrographic) classifications and terminology, and (2) integration of petrographic and geochemical results. These objectives were met by completing questionnaires, and petrographic, geochemical and photomicrograph round-robin exercises. Samples that were selected for this study represent different petrographic and geochemical properties, and geologic settings to help identify issues related to the utilization of different classifications and techniques. Petrographic analysis of the organic matter was completed using both a prescribed classification and the individual classification normally used by each participant. Total organic carbon (TOC), Rock-Eval pyrolysis and elemental analysis were also completed for each sample. Significant differences exist in the petrographic results from both the prescribed and individual classifications. Although there is general agreement about the oil- vs gas-prone nature of the samples...

Carbon Stocks and Isotopic Composition of the Organic Matter in Soils Covered by Native Vegetation and Pasture in Sorocaba, SP, Brazil

SILVA, A. M.; NOGUEIRA, D. P.; IKEMATSU, P.; SILVEIRA, F. M.; BOMBACK, M.; ALVES, S. H.; PAULA, F. P.; CAMARGO, P. B.
Fonte: UNIV TEHRAN Publicador: UNIV TEHRAN
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
669.032%
Land cover change constitutes one of main way of alteration of soil organic matter in both quantitative and qualitative terms. The goal of this study was to compare the carbon stock and the isotopic signature of the organic matter in the soil of areas with different land use,covered with forest and grass (pasture). The study area is located at Sorocaba, SP, Brazil. Using un-deformed soil samples, we measured the carbon content and bulk density. The isotopic signature of soil carbon was determined through the analysis of isotopic ratio (12)C/(13)C. The pasture soil stocks 48% less carbon than the soil covered by natural forest. The isotopic signature indicated that 42.2% of organic matter of the soil covered by pasture is originated from grasses. This characterizes a highly degradation of organic matter in the environment, both quantitatively and qualitatively. Hence, some guidelines of recuperation are described in order to restore the soil organic matter, structure and porosity.; FAPESP[05/15796-6]

Benthic responses to organic matter variation in a subtropical coastal area off SE Brazil

QUINTANA, Cintia O.; YOSHINAGA, Marcos Y.; SUMIDA, Paulo Y. G.
Fonte: WILEY-BLACKWELL PUBLISHING, INC Publicador: WILEY-BLACKWELL PUBLISHING, INC
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
670.9325%
Organic matter quality, expressed as the proportion of chlorophyll a (Chl a) to degraded organic material (i.e. phaeopigments), is known to influence the structure of benthic associations and plays an important role in the functioning of the ecosystem. This study investigates the vertical distribution of microbial biomass, meiofauna and macrofauna with respect to organic matter variation in Ubatuba, Brazil, a southeastern, subtropical coastal area. On three occasions, samples were collected in exposed and sheltered stations, at high and low hydrodynamic conditions. We hypothesize that benthic assemblages will have high meio- and macrofaunal densities and high microbial biomass at the sediment surface at the sheltered site, and lower and vertically homogeneous microbial biomass and densities of meio- and macrofauna are expected at the exposed site. The accumulation of fresh organic matter at the sediment surface was observed at both stations over the three sampling dates, which contributed to the higher densities of meiofauna in the first layers of the sediment column. Macrofauna followed the same trend only at the exposed station, but changes in the number of species, biodiversity and feeding groups were registered for both stations. Microbial biomass increased at the sheltered station over the three sampling dates...

Influência da quantidade e qualidade da matéria orgânica sedimentar na estrutura e distribuição vertical e horizontal das comunidades bentônicas na plataforma de São Sebastião, São Paulo, Brasil; Influence of sedimentary organic matter quantity and quality on the structure, vertical and horizontal distribution of benthic communities in the São Sebastião shelf, São Paulo, Brazil

Caballero, Natalia Venturini
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 14/03/2008 PT
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Os ambientes costeiros marinhos são sítios de uma intensa produção, movimentação e enterramento de carbono orgânico, já que uma fração substancial do material orgânico produzido na zona eufótica deposita-se nos sedimentos e constitui a principal fonte de alimento para o bentos. O objetivo geral deste trabalho é estudar a influência da quantidade, origem e qualidade (composição bioquímica) da matéria orgânica sedimentar sobre a estrutura e distribuição vertical e horizontal da meiofauna e macrofauna bentônicas, em três ambientes com aportes diferenciados de matéria orgânica e submetidos a duas condições oceanográficas diferentes. Foram realizadas 2 campanhas de coleta em 6 estações localizadas no Canal de São Sebastião (CSS), Enseada de Caraguatatuba e Baía de Castelhanos. Em cada estação, foram analisadas as variáveis físico-químicas da água do mar, topografia do fundo, taxa de sedimentação atual. Coletaram-se amostras de sedimentos para análise das características granulométricas, concentração de pigmentos fotossintéticos, teores de matéria orgânica, carbono orgânico, nitrogênio e enxofre total, biopolímeros orgânicos (carboidratos, lipídios e proteínas), concentração e composição dos ácidos graxos...

Variações na acumulação de matéria orgânica, ao longo do holoceno, em sedimentos da região costeira de Ubatuba-São Paulo; Changes in the organic matter accumulation, during holocene, in coastal sediments from Ubatuba region-São Paulo

Sonvesso, Simone Sandra
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 02/04/2007 PT
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Mudanças na taxa de acumulação e na natureza da matéria orgânica sedimentar, e suas relações com as variações climáticas e flutuações do nível relativo do mar durante os últimos 8.500 anos cal. A.P. foram investigadas em dois testemunhos provenientes do Saco de Ribeira, Enseada do Flamengo, e junto à praia do Lázaro, Enseada da Fortaleza, na região de Ubatuba, litoral norte do Estado de São Paulo. Para o estudo as amostras coletadas foram submetidas a diversas análises - granulometria, teor de CaCO3, teores de Carbono orgânico, Nitrogênio e Enxofre totais, e razões isotópicas de carbono. Datações 14C, calibradas para a idade calendário, permitiram estabelecer um modelo de idades para as variações sedimentares detectadas. Intervalos de clima mais quente, 8.000-6.000 anos cal. A.P., foram acompanhados de um aumento na taxa de acumulação de carbono T.A.C. (10-13 g m-2 ano-1), seguida de diminuição após 5.000 anos cal. A.P., para valores inferiores a 2 g m-2 ano-1. Variações climáticas regionais, possivelmente relacionadas a chuvas torrenciais, próximos ao máximo transgressivo, de 5.100 anos 14C A.P., foram detectadas pelo aumento nos valores de T.A.C. (10-12 g. m- 2 ano-1), aumento nas taxas de acumulação de massa (T.A.M.) e deposição de sedimentos mais grossos...

Eficiência agronômica de fertilizantes fosfatados em solos com diferentes capacidades de adsorção de fósforo e teores de matéria orgânica; Agronomic efficiency of phosphate fertilizers in soils with different capacity of phosphate adsorption and organic matter levels

Matias, Gean Carlos Silva
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 12/05/2010 PT
Relevância na Pesquisa
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Os solos tropicais altamente intemperizados apresentam elevada capacidade de adsorção de fósforo. Vários fatores podem influenciar a adsorção de P nestes solos, dentre eles destaca-se o teor de matéria orgânica. Os mecanismos envolvidos neste processo estão relacionados à liberação de ácidos orgânicos oriundos da decomposição da matéria orgânica, podendo ser de baixa massa molecular tais como, malato, oxalato ou citrato, ou de elevada massa molecular como ácidos húmicos e fúlvicos, que atuam na complexação do Fe ou Al em solução ou na superfície dos colóides, que por meio de troca de ligantes reduz assim a adsorção de P. O presente trabalho constou de quatro estudos, ambos realizados em casa-de-vegetação do Departamento de Ciência do Solo da ESALQ/USP, tendo como objetivos: (i) verificar o efeito da adição de ácidos orgânicos e fontes de substâncias húmicas, na disponibilidade de P em solos com diferentes capacidades de adsorção. Os tratamentos compreenderam 2 tipos de solo (Latossolo vermelho amarelo - LVA e LV), 2 fontes de P (Fosfato monocálcico - FMC p.a. e Fosfato natural reativo de Arad - FNR), 2 fontes de ácidos orgânicos de baixa massa molecular - AOBM (ácido cítrico - AC e ácido oxálico - AO)...

Caracterização da matéria orgânica de solo irrigado com efluente de estação de tratamento de esgoto; Characterization of organic matter from treated sewage effluent irrigated soils

Noirtin, Eric Louis Roger
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 16/11/2010 PT
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Diante dos recentes estudos sobre as mudanças climáticas, a preocupação sobre a repartição e a disponibilidades dos recursos hídricos é cada vez maior, estimulando pesquisas sobre métodos de reuso de água. Dentre estes métodos, o uso de efluente de estação de tratamento de esgoto (EETE) para irrigação de culturas agrícolas apresenta várias vantagens, como por exemplo, suprir a necessidade hídrica das plantas e fornecer nutrientes essenciais ao seu desenvolvimento, evitar o despejo dos efluentes nos corpos dágua e ainda poderia ser considerado como um tratamento complementar dos esgotos tratados. Entretanto, os impactos nos solos tropicais que o uso de efluentes para irrigação agrícola podem causar precisam ser melhores conhecidos. Desta forma, pesquisas vêm sendo realizadas desde 2002 no campo experimental de reuso de água em Lins (SP) cujos objetivos visam a sustentabilidade do uso de efluente de tratamento de esgoto para irrigação de culturas agrícolas. Entre as culturas ali estudadas selecionou-se para o desenvolvimento deste trabalho de doutorado, a área cultivada com capim-Bermuda Tifton 85 e o foco da pesquisa foi avaliar os efeitos da irrigação com efluente sobre a matéria orgânica do solo (MOS). O delineamento experimental foi de blocos completos casualisados com três tratamentos e quatro repetições e o período do experimento em campo foi de junho de 2007 a junho de 2009. Os tratamentos avaliados foram SI: sem irrigação e sem fertilização...

Estudo do melhoramento do solo utilizando resíduos gerados na cadeia produtiva da cana-de-açúcar: uma avaliação da matéria orgânica do solo empregando técnicas espectroscópicas; Study of soil amendment under sugar mill waste: an organic matter assessment with spectroscopic techniques

Carvalho, Camila Miranda
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 12/05/2015 PT
Relevância na Pesquisa
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Em face ao bom desempenho da agricultura brasileira, cresce também a responsabilidade por uma produção sustentável. Particularmente, o sistema produtivo da cana-de-açúcar vem se adaptando a uma produção sem queima, e busca formas alternativas de manejo dos resíduos da produção que sejam sustentáveis tanto economicamente, quanto ambientalmente. Neste trabalho apresentamos resultados dos tratamentos de solo agriculturável com resíduos de i) cinzas de bagaço de cana aplicado em cobertura e ii) torta de filtro na entrelinha da cultura, em diferentes doses. Avaliamos o impacto desses tratamentos no conteúdo de carbono e na matéria orgânica do solo. Para determinar se os tratamentos podem ser considerados sequestradores de carbono e ambientalmente sustentáveis nos detemos na preservação seletiva como mecanismo de retenção da matéria orgânica do solo, a qual leva a acumulação de componentes orgânicos químicos mais recalcitrantes. Utilizamos as técnicas espectroscópicas de fluorescência de luz UV-Visível, espectroscopia de fluorescência matriz excitação-emissão para avaliar a fração de ácido húmico do solo e o aumento da recalcitrância química...

Co-accumulation of microbial residues and particulate organic matter in the surface layer of a no-till Oxisol under different crops

Martins, Marcio R.; Angers, Denis A.; Cora, Jose E.
Fonte: Pergamon-Elsevier B.V. Ltd Publicador: Pergamon-Elsevier B.V. Ltd
Tipo: Artigo de Revista Científica Formato: 208-213
ENG
Relevância na Pesquisa
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); In the absence of significant mechanical disturbance such as under permanent no-till (NT), crop type should be a prominent factor controlling soil organic C (SOC) pools. Microbial cell residues have been shown to be influenced by plant species and are believed to contribute significantly to soil organic matter formation. We performed a study to investigate the co-accumulation of microbial cell wall residues (glucosamine, GlcN and muramic acid, MurN) and organic C (total and particle-size fractions) in the surface layer (0- to 5-cm depth) of an Oxisol after 7 yr under NT, as affected by different crop types. SOC content associated with pigeon pea [Cajanus cajan (L) Millsp.] was 20% and 18% higher than that with corn (Zea mays L) or sunflower (Helianthus annuus L.), respectively. The highest particulate organic C (POC) content in soil was also found under pigeon pea, which showed values 54, 46, and 48% higher than under corn, sunflower, and oilseed radish (Raphanus sativus L var. oleiformis Pers.), respectively. Changes in POC explained most of the variation in SOC. The positive impact of pigeon pea on POC and SOC was attributed to rapid decomposition of its residues...

Carbon Stocks and Isotopic Composition of the Organic Matter in Soils Covered by Native Vegetation and Pasture in Sorocaba, SP, Brazil

Silva, A. M.; Nogueira, D. P.; Ikematsu, P.; Silveira, F. M.; Bomback, M.; Alves, S. H.; Paula, F. P.; Camargo, P. B.
Fonte: Univ Tehran Publicador: Univ Tehran
Tipo: Artigo de Revista Científica Formato: 435-440
ENG
Relevância na Pesquisa
669.032%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Processo FAPESP: 05/15796-6; Land cover change constitutes one of main way of alteration of soil organic matter in both quantitative and qualitative terms. The goal of this study was to compare the carbon stock and the isotopic signature of the organic matter in the soil of areas with different land use,covered with forest and grass (pasture). The study area is located at Sorocaba, SP, Brazil. Using un-deformed soil samples, we measured the carbon content and bulk density. The isotopic signature of soil carbon was determined through the analysis of isotopic ratio (12)C/(13)C. The pasture soil stocks 48% less carbon than the soil covered by natural forest. The isotopic signature indicated that 42.2% of organic matter of the soil covered by pasture is originated from grasses. This characterizes a highly degradation of organic matter in the environment, both quantitatively and qualitatively. Hence, some guidelines of recuperation are described in order to restore the soil organic matter, structure and porosity.

Cover crops and no-till effects on physical fractions of soil organic matter

Nascente, Adriano Stephan; Li, Yuncong C.; Crusciol, Carlos Alexandre Costa
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 52-57
ENG
Relevância na Pesquisa
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Physical fractions (free light fraction, intra-aggregate light fraction and heavy fraction) of soil organic matter (SOM) are good indicators of soil quality for sustainable land use. The objective of this study was to evaluate the effect of cover crops on total organic carbon (TOC) and physical fractions of soil organic matter in soil under a no-tillage system (NTS) and a conventional tillage system (CTS, one plowing and two disking). A three-year field experiment was carried out as a cover crop-rice (Oryza sativa)-cover crop-rice rotation. Treatments included cover crops (Panicum maximum, Brachiaria ruziziensis, Brachiaria brizantha, and pearl millet (Pennisetum glaucum), fallow, till or no till. The SOM was physically fractionated in free light fraction (FLF), intra-aggregates light fraction (IALF) and heavy fraction (HF). The levels of C in whole soil were also evaluated, as well as C in the light fractions (FLF+IALF) and in the HF. Results indicated that concentrations of C in the FLF and IALF in surface soils (0-0.05m) were much higher (10.8 and 1.95gkg-1, respectively) than that in the 0.05-0.1m soil depth (7.68 and 1.54gkg-1, respectively) and in the 0.1-0.2m soil depth (4.98 and 1.24gkg-1, respectively). The NTS resulted in higher levels of FLF (12.2gkg-1) and IALF (2.19gkg-1) than with CTS (1.37-7.30gkg-1). Millet had the highest C (19.5gkg-1) and N (1.1gkg-1) concentrations in soil. There was an accumulation of TOC and total N in the surface soil with cover crops...

Effects of organic and inorganic amendments on soil organic matter properties

LIMA, Diana L D; SANTOS, Sérgio M; SCHERER, HW; Rudolf Schneider; Armando Duarte; EDuarda Santos; Valdemar Esteves
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
672.7911%
The aim of this work was to investigate the effects of long-term application of different organic fertilizers (sewage sludge, farmyard manure, compost) as compared to mineral fertilizer on the structure of the soil organic matter. Capillary electrophoresis was employed for the quantification of monosaccharides and phenolic compounds, whereas NMR and FT-IR were used for the overall characterization of the soils organic matter. Application of farmyard manure results in a higher content of organic matter derived from angiosperms, suggested by the higher levels of syringic and vanillic phenols. Spectroscopic studies show an increase of lignin and lignin-like products in the organic matter of the soil, which may be derived from the cereal straw supplied with farmyard manure. According to spectroscopic analysis, 13C CPMAS-NMR and FT-IR spectra, higher contents of methylene groups (– CH2) from proteins and protein-like compounds, as well as higher levels of carbohydrates, were found in the soil supplied with compost. The monosaccharide (rhamnose, xylose, glucose, mannose, arabinose, fucose and galactose) content was not significantly influenced by the different organic fertilizers, suggesting that the type of amendment used does not affect any of these six studied monomers. Comparing the three organic amendments the most significant differences were observed after long-term application of farmyard manure...

Spatial distribution of organic matter in the surface sediments of Ubatuba Bay (Southeastern - Brazil)

BURONE,LETICIA; MUNIZ,PABLO; PIRES-VANIN,ANA MARIA S.; RODRIGUES,MARCELO
Fonte: Academia Brasileira de Ciências Publicador: Academia Brasileira de Ciências
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2003 EN
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Analyses of organic matter content, organic carbon, nitrogen, sulfur and granulometric variables were performed on 101 surface sediment samples from Ubatuba Bay in order to investigate the spatial distribution of organic matter, its origin and the relationships among its components. The samples were obtained with a manual corer, from water depths between 1 and 15m during 5 cruises of the R/V "Veliger II', two months apart. Pearson correlation, regression and Principal Component Analysis (PCA) statistical methods were used to analyze the data. Strong correlations between organic matter and fine sediment fractions were obtained. The PCA revealed at least two main sample groups that reflect the different environmental conditions prevalent in the bay. There is a simple linear relationship between organic carbon content and the organic matter content determined by the calcination technique. Taking into account that the analysis of organic matter content is less expensive and less time consuming than the analysis of organic carbon, the present method of estimation can be useful when fast evaluation of the organic carbon content is needed for samples from similar environments.

Transformations in occluded light fraction organic matter in a clayey oxisol: evidence from 13C-CPMAS-NMR and delta13C Signature

Roscoe,R.; Buurman,P.; van Lagen,B.; Velthorst,E.
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2004 EN
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We hypothesised that, during occlusion inside granular aggregates of oxide-rich soils, the light fraction organic matter would undergo a strong process of decomposition, either due to the slow process of aggregate formation and stabilisation or due to digestion in the macro- and meso-fauna guts. This process would favour the accumulation of recalcitrant materials inside aggregates. The aim of this study was to compare the dynamics and the chemical composition of free and occluded light fraction organic matter in a natural cerrado vegetation (woodland savannah) and a nearby pasture (Brachiaria spp.) to elucidate the transformations during occlusion of light fraction in aggregates of a clayey Oxisol. Nuclear Magnetic Resonance of the 13C, with Cross Polarisation and Magic Angle Spinning (13C-CPMAS-NMR), and 13C/12C isotopic ratio were combined to study organic matter composition and changes in carbon dynamics, respectively. The occluded light fraction had a slower turnover than the free light fraction and the heavy fraction. Organic matter in the occluded fraction also showed a higher degree of decomposition. The results confirm that processes of soil organic matter occlusion in the typical "very fine strong granular" structure of the studied oxide-rich soil led to an intense transformation...

The role of soil organic matter in sustainable crop production in the Tropics.

FAGERIA, N. K.; FERREIRA, E. P. B.; KNUPP, A. M.
Fonte: In: INTERNATIONAL SYMPOSIUM ON SOIL ORGANIC MATTER, 3., 2011, Leuven. Organic matter dynamics - from soils to oceans: book of abstracts. Leuven, Belgium: European Science Foundation, 2011. Publicador: In: INTERNATIONAL SYMPOSIUM ON SOIL ORGANIC MATTER, 3., 2011, Leuven. Organic matter dynamics - from soils to oceans: book of abstracts. Leuven, Belgium: European Science Foundation, 2011.
Tipo: Resumo em anais de congresso (ALICE) Formato: p. 195.
EN
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Soil organic matter has long been recognized as important indicator of soil productivity.; 2011

Extraction and Concentration of Freshwater – and Seawater – Derived Dissolved Organic Matter for Use in Aquatic Toxicology Studies

Rodrigues, Sandra Carvalho; Bianchini, Adalto
Fonte: Universidade Federal do Rio Grande Publicador: Universidade Federal do Rio Grande
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
668.3645%
Dissolved organic matter (DOM) is defined as the organic matter that passes through a 0.45 μm-mesh filter. Recent studies have shown the DOM importance in mitigating trace metals and organic pollutants toxicity. In general, studies with DOM are performed using commercial organic matter. However, it has been demonstrated that this organic matter has little structural similarity with the aquatic humic acids. Furthermore, a natural DOM is composed by different fractions, which can exhibit different complexing properties with metals. Thus, it is important to evaluate the effect of different sources of natural DOM on pollutants toxicity. To use natural DOM in aquatic toxicity tests, it is necessary to extract and provide suitable storage for samples in the laboratory. The ideal process for DOM isolation from natural waters should be capable of rapidly and effectively extracting large quantities of DOM from water without fractionation, chemical alteration and/or other losses. Therefore, in the present paper we describe the methodological approaches currently in use in our laboratory for extraction and concentration of both freshwater and seawater-derived DOM using reverse osmosis (freshwater) and solid phase extraction (seawater).; Extração e concentração de matéria orgânica dissolvida de águas doce e marinha para uso em estudos de toxicologia aquática A matéria orgânica dissolvida (MOD) é definida como a matéria orgânica que passa através de uma membrana de 0...

Compartimentos da matéria orgânica do solo sob sistemas de manejo e vegetação natural de cerrado; Soil organic matter pools under management systems and natural Cerrado vegetation

FIGUEIREDO, Cícero Célio de
Fonte: Universidade Federal de Goiás; BR; UFG; Doutorado em Agronomia; Ciências Agrárias Publicador: Universidade Federal de Goiás; BR; UFG; Doutorado em Agronomia; Ciências Agrárias
Tipo: Tese de Doutorado Formato: application/pdf
POR
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Different soil organic matter pools under management systems and natural Cerrado vegetation were studied. These pools were estimated using their carbon and nitrogen contents. Total soil organic carbon and total nitrogen (COT and NT), carbon and nitrogen of particulate organic matter (COP and NP), mineral-associated organic carbon and nitrogen (COM and NM), particulate organic carbon associated with different aggregates size classes (COPA), microbial biomass carbon and nitrogen contents (CBM and NBM) and their relations, and basal respiration as a measure of microbial activity, were determined in this study. Eight treatments were used: seven soil management systems and an undisturbed area of Savanna type vegetation, Cerrado, as a reference. They were: heavy disk harrow and legume species cultivation during twelve years (GP); disk plow and legume species cultivation during twelve years (AD); minimum tillage with chisel plow starting five years after installing the experiment (ESC); no-tillage with biennial crop rotation: grass and legume species as cover crop (PD1); no-tillage with crop rotation and annual cover crops (PD2), no-tillage with annual crop rotation of grass and legume species (PD3), permanent pasture (PAST) and natural savanna vegetation...

Dissolved organic matter dynamics and microbial activity in salt-affected soils.

Mavi, Manpreet Singh
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2012
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Salt-affected soils (comprising saline and sodic soils) contain excessive amounts of salts and cover over 10 % of the world’s arable land. They are a serious land-degradation problem because a) salinity causes poor plant growth and low microbial activity due to osmotic stress, ion toxicity and imbalanced nutrient uptake and b) plant growth in sodic soils is limited by poor soil structure and aeration. As a consequence of the poor plant growth, salt-affected soils have low organic matter content. Therefore, to minimise soil degradation, it is important to understand the processes in salt-affected soils particularly those involved in nutrient cycling. Dissolved organic matter (DOM) is the most labile portion of soil organic matter pools and affects many biogeochemical processes such as nutrient cycling, translocation and leaching, microbial activity and mineral weathering. Even though it only comprises a small portion of the total organic matter (< 1 %), it can be used to determine changes in soil C dynamics prior to detection in the total SOM pool. Salinity and sodicity influence organic matter turnover by affecting the amount of plant material entering the soil as well as the rate of decomposition. While the effects of salinity and sodicity on soil microorganisms and soil organic matter turnover have been studied separately...

The water-soluble organic fraction and its relationships to the degree of maturity of organic matter during composting

Sánchez-Monedero, Miguel Ángel; Roig, Asunción; Bernal Calderón, M. Pilar
Fonte: ORBIT 2001 Publicador: ORBIT 2001
Tipo: Artículo Formato: 299785 bytes; application/pdf
ENG
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The evolution of different components of the water-soluble organic matter, water soluble carbon (COW), carbohydrates and phenols were studied during the composting of six different mixtures of organic wastes prepared with sweet sorghum bagasse, cotton waste, sewage sludge, municipal solid waste, urea, pine bark and brewery sludge. The COW, carbohydrate and phenol concentrations decreased in the six composting mixtures as a consequence of the organic matter degradation carried out by the microbial activity. The intensity of this organic matter degradation and the evolution of the water-soluble compounds depended on the kind of material used in the starting mixtures. Therefore, these parameters were not considered suitable to be used as the basis for a general organic matter stabilisation index. The changes in the water-soluble organic carbon to water-soluble organic nitrogen ratio (COW/NOW) and the water-soluble organic carbon to total organic nitrogen ratio (COW/NOT) were considered to be suitable as general stabilisation indices since these ratios did not depend on the material used. The evolution of these two ratios showed a similar pattern during the composting of the six mixtures studied. All mature composts reached values for these ratios which were in agreement with the ranges proposed by other authors with other type of materials. These maturity indices were also compared with Lepidium Sativum L. germination assays and no phytotoxic effects were found in materials with COW/NOW and COW/NOT ratios values between the limits established for mature composts (COW/OW between the range 5-6...

An accurate record of volcanic ash fall deposition as characterized by dispersed organic matter in a Lower Permian tonstein bed (Faxinal Coalfield, Paraná Basin, Brazil)

Simas, M.W.; Guerra-Sommer, M.; Mendonça, J.G.; Cazzulo-Klepzig, Filho M.; Formoso, M.L.L.; Degani-Schmidt, I.
Fonte: Universidade Autônoma de Barcelona Publicador: Universidade Autônoma de Barcelona
Tipo: Artigo de Revista Científica Formato: application/pdf
Publicado em //2013 ENG
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For the first time, the dispersed organic matter in the tonstein layer interbedded with a coal seam in the Faxinal Coalfield (Sakmarian, Southern Paraná Basin, Brazil) is characterized. The deposition of clusters of pollen grains was highly influenced by the intense ash fall process that probably occurred during seasonal dehiscence of reproductive structures. The well-preserved phytoclasts with their upper and lower leaf cuticles stuck together indicate that the rapid fall of ash on this material hindered organic biodegradation. The preservation of seemingly autochthonous Botryococcus colonies at the top of the tonstein layer is evidence of the subaqueous deposition of this layer. The darkening in cuticles and xylem phytoclasts can be attributed to different causes: the thermal influence of ash fall during deposition, chemical effects of the ash, prolonged oxidation of organic matter in low water level conditions or the burning of plant organs by wildfires. Analyses of dispersed organic matter along the tonstein layer showed that the organic matter succession reflects the composition of different plant strata (herbaceous pteridophytes and arboreal glossopterids-cordaitaleans) around the deposition site.