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| Registros recuperados: 44 | |
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| FERNANDES, F. A.; CERRI, C. C.; FERNANDES, A. H. B. M.. |
| Estudou-se uma cronosseqüência de introdução de pastagens cultivadas em áreas com 10 e 20 anos de implantação, tendo uma área de Cerrado intacto como referência. Coletaram-se amostras até 40cm de profundidade ao longo de dois transectos, para cálculo dos estoques de C e N e determinações químicas. Também abriram-se trincheiras e coletaram-se amostras de solo até 1m de profundidade, para estudo das variações nos conteúdos de C e N no perfil. Após 10 anos de cultivo, o solo apresentou aumento no teor de bases trocáveis e na capacidade de troca catiônica, e diminuição da acidez. Entretanto, após 20 anos, os teores de bases trocáveis e a capacidade de troca catiônica diminuíram e a acidez aumentou, indicando tendência do sistema de retornar ao equilíbrio... |
| Tipo: Boletim de Pesquisa e Desenvolvimento (INFOTECA-E) |
Palavras-chave: Característica química; Bases trocáveis; Carbono orgânico; Frações húmicas; Chemical characteristics; Organic carbon; Humic fractions; Cultivated pasture.; Acidez; Fracionamento; Matéria Orgânica; Nitrogênio; Pastagem Cultivada; Solo.; Acidity; Pantanal; Fractionation; Exchangeable cations; Organic matter; Nitrogen; Soil.. |
| Ano: 2002 |
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/810747 |
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| Bertoni, R. |
| The radiochemical methods proposed for evaluating heterotrophic activity in waters have been severely criticized in recent years because they are not considered to be sufficiently realistic. Thus, the possibility of directly measuring the heterotrophic consumption of naturally occurring Organic Carbon (OC) in fresh water samples incubated under controlled conditions has been evaluated. The analytical performances of two OC analyzers utilizable for this purpose are discussed here, and some examples of the results obtained by the direct measurement of OC consumption are presented. The consumption rates thus measured ranged from 11.6 to 50.2 mu gC/ 1.h. Although the technique discussed here is less sensitive than radiochemical methods, the few assumptions... |
| Tipo: Text |
Palavras-chave: Biogeochemistry; Microbiology; Carbon cycle; Organic carbon; Water; Heterotrophic organisms; Analytical techniques. |
| Ano: 1984 |
URL: http://archimer.ifremer.fr/doc/1984/acte-950.pdf |
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| Pisapia, Celine; Gerard, Emmanuelle; Gerard, Martine; Lecourt, Lena; Lang, Susan Q.; Pelletier, Bernard; Payri, Claude E.; Monnin, Christophe; Guentas, Linda; Postec, Anne; Quemeneur, Marianne; Erauso, Gael; Menez, Benedicte. |
| Despite their potential importance as analogs of primitive microbial metabolisms, the knowledge of the structure and functioning of the deep ecosystems associated with serpentinizing environments is hampered by the lack of accessibility to relevant systems. These hyperalkaline environments are depleted in dissolved inorganic carbon (DIC), making the carbon sources and assimilation pathways in the associated ecosystems highly enigmatic. The Prony Bay Hydrothermal Field (PHF) is an active serpentinization site where, similar to Lost City (Mid-Atlantic Ridge), high-pH fluids rich in H-2 and CH4 are discharged from carbonate chimneys at the seafloor, but in a shallower lagoonal environment. This study aimed to characterize the subsurface microbial ecology of... |
| Tipo: Text |
Palavras-chave: Serpentinization; Alkaline hydrothermalism; Deep life; Firmicutes; Acetothermia; Omnitrophica; Organic carbon. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00467/57909/60314.pdf |
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| Jennerjahn, Tc; Ittekkot, V. |
| The nature of sedimentary organic matter from mangroves and the continental margin of eastern Brazil (8 degrees-24 degrees S) has been investigated in order to obtain information on sources and diagenetic processes. The organic matter content of mangrove sediments is three to four times higher than the maximum content of continental margin sediments. Downslope distribution of organic carbon, nitrogen, amino acids and hexosamines shows an enrichment in water depths between 800 m and 1000 m. The distribution of individual amino acids and hexosamines is highly variable in sedimentary organic matter from mangroves and the continental margin, and the observed compositional differences are mainly due to diagenetic alteration. Organic matter is highly reactive in... |
| Tipo: Text |
Palavras-chave: Organic carbon; Amino acids; Carbon cycle; Mangroves; Continental margin. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00093/20403/18070.pdf |
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| Aracena, Claudia; Lange, Carina B.; Iriarte, Jose Luis; Rebolledo, Lorena; Pantoja, Silvio. |
| The Chilean Patagonian fjords region (41-56 degrees S) is characterized by highly complex geomorphology and hydrographic conditions, and strong seasonal and latitudinal patterns in precipitation, freshwater discharge, glacier coverage, and light regime; all of these directly affect biological production in the water column. In this study, we compiled published and new information on water column properties (primary production, nutrients) and surface sediment characteristics (biogenic opal, organic carbon, molar C/N, bulk sedimentary delta(13)C(org)) from the Chilean Patagonian fjords between 41 degrees S and 55 degrees S, describing herein the latitudinal pattern of water column productivity and its imprint in the underlying sediments. Based on information... |
| Tipo: Text |
Palavras-chave: Biogenic opal; Organic carbon; Stable carbon isotopes; Primary production; Fjords; Patagonia. |
| Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00214/32519/30998.pdf |
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| Baudin, François; Rabouille, Christophe; Dennielou, Bernard. |
| We address the role of the Congo River sediment dispersal in exporting and trapping organic carbon into deep offshore sediments. Of particular interest is the Congo submarine canyon, which constitutes a permanent link between the terrestrial sediment sources and the marine sink. The Congo River delivers an annual sediment load of ~40 Tg (including 2 Tg of C) that feed a mud-rich turbidite system. Previous estimates of carbon storage capacity in the Congo turbidite system suggest that the terminal lobe complex accounts for ~12% of the surface area of the active turbidite system and accumulates ~18% of the annual input of terrestrial particulate organic carbon exiting the Congo River. In this paper, we extend the approach to the whole active turbidite... |
| Tipo: Text |
Palavras-chave: Recent sediments; Congo turbidite system; Organic carbon; Burial efficiency; Source-to-sink. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00622/73394/72611.pdf |
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| Montalvo, J. F.. |
| Los sedimentos superficiales de las bahías de Cárdenas y Santa Clara fueron muestreados en mayo de 2002 y julio de 2005, evaluándose los parámetros orgánicos e inorgánicos que tienen mayor peso en los ciclos biogeoquímicos (carbón, nitrógeno, fósforo, carbonatos, sulfuro de hidrógeno y consumo de oxidante químico). Los sedimentos de las bahías de Cárdenas y Santa Clara, poseen notables contenidos de carbón orgánico y concentraciones de nitrógeno inferiores a 0,2 %, evidenciando que la fuente principal de materia orgánica en estos cuerpos de agua es la vegetación periférica y acuática, rica en carbono y pobre en nitrógeno. En estas bahías las concentraciones promedio de carbonatos son superiores al 35 %, aunque la mayor riqueza corresponde a la bahía de... |
| Tipo: Journal Contribution |
Palavras-chave: Sediments; Organic carbon; Nitrogen; Hydrogen sulphide; Bays; Nitrogen; Hydrogen sulphide; Http://aims.fao.org/aos/agrovoc/c_5192; Http://aims.fao.org/aos/agrovoc/c_15986. |
| Ano: 2006 |
URL: http://hdl.handle.net/1834/3342 |
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| Montalvo, J. F.; Loza, S.. |
| Se construyeron y modelaron los resupuestos y procesos biogeoquímicos de carbón, nitrógeno y fósforo para tres muestreos (Julio/2004, Abril y Diciembre/2005) en un cuerpo de agua de semi-cerrado e hipersalino como la Bahía de Jigüey. Se colectaron muestras de agua para medir los parámetros hidroquímico s relacionados con el sistema, nutrientes inorgánicos (nitratos + nitrito, amonio y fósforo), la demanda química de oxígeno, nitrógeno total y fósforo total. En la etapa de la investigación la salinidad varió entre 50 y 95 ups y se calcularon los presupuestos de carbón y nutrientes por muestreo. El flujo de fósforo inorgánico (ΔIP) en la bahía está alrededor de -2,06 mmol m-2 d-1, y equivale a una producción promedio de carbón orgánico por vía fotosintética... |
| Tipo: Journal Contribution |
Palavras-chave: Nutrients (mineral); Organic carbon. |
| Ano: 2006 |
URL: http://hdl.handle.net/1834/3336 |
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| Balbinot Junior,Alvadi Antonio; Veiga,Milton da; Moraes,Anibal de; Pelissari,Adelino; Mafra,Álvaro Luiz; Piccolla,Cristiano Dela. |
| The objective of this work was to evaluate the effect of winter land use on the amount of residual straw, the physical soil properties and grain yields of maize, common bean and soybean summer crops cultivated in succession. The experiment was carried out in the North Plateau of Santa Catarina state, Brazil, from May 2006 to April 2010. Five strategies of land use in winter were evaluated: intercropping with black oat + ryegrass + vetch, without grazing and nitrogen (N) fertilization (intercropping cover); the same intercropping, with grazing and 100 kg ha-1 of N per year topdressing (pasture with N); the same intercropping, with grazing and without nitrogen fertilization (pasture without N); oilseed radish, without grazing and nitrogen fertilization... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Compaction; Cover crops; Crop-livestock integration; No-tillage; Organic carbon. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2011001000032 |
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| Kunde,Roberta Jeske; Lima,Cláudia Liane Rodrigues de; Silva,Sérgio Delmar dos Anjos e; Pillon,Clenio Nailto. |
| Abstract: The objective of this work was to evaluate the tensile strength, friability, aggregation, and the physical fractions of soil organic matter of a Rhodic Hapludox cultivated with sugarcane (Saccharum officinarum). The treatments consisted of one, three, and five years of cultivation of sugarcane, in the state of Rio Grande do Sul, Brazil. As a reference, a native forest adjacent to the cultivation area, with soil and relief characteristics similar to those of the cultivation areas, was used. Deformed samples were collected at 0.00-0.05, 0.05-0.10, and 0.10-0.20-m soil depths, for the determination of the soil physical attributes and for the physical fractionation of particle-size and density of the organic matter. The physical attribute evaluations... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Saccharum officinarum; Organic carbon; Organic matter fractionation; Soil physical quality. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2018000400487 |
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| TAKESHITA,V.; MENDES,K.F.; ALONSO,F.G.; TORNISIELO,V.L.. |
| ABSTRACT: With extensive use of herbicides in agricultural areas, the risk of contamination of groundwater and surface water by these products has become a worldwide concern. Practices of application or maintenance of soil organic residues that have begun to be used in agriculture for soil nutrition have demonstrated other benefits besides nutrient supplementation, such as reduced mobility and increased soil degradation of herbicides. Because it is the final destination of herbicides, soil and its constituents, especially organic matter in tropical soils, play a prominent role in processes that encompass the dynamics of herbicide molecules. In this context, it is necessary to know the influence of the organic matter and its constituents on the behavior of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Sorption; Mobility; Biodegradation; Organic carbon. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582019000100304 |
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| Cardoso,José Alberto Ferreira; Lima,Augusto Miguel Nascimento; Cunha,Tony Jarbas Ferreira; Rodrigues,Marcos Sales; Hernani,Luis Carlos; Amaral,Andre Julio do; Oliveira Neto,Manoel Batista de. |
| Improper land use has lead to deterioration and depletion of natural resources, as well as a significant decline in agricultural production, due to decreased soil quality. Removal of native vegetation to make way for agricultural crops, often managed inadequately, results in soil disruption, decreased nutrient availability, and decomposition of soil organic matter, making sustainable agricultural production unviable. Thus, the aim of the present study was to evaluate the impact of growing irrigated mango (over a 20 year period) on the organic carbon (OC) stocks and on the fractions of soil organic matter (SOM) in relation to the native caatinga (xeric shrubland) vegetation in the Lower São Francisco Valley region, Brazil. The study was carried out on the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Mangifera indica; Organic carbon; Humic substances; Heavy fraction; Semiarid region. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832015000401068 |
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| Registros recuperados: 44 | |
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