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| Registros recuperados: 41 | |
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| Silva,Jéssica C. N.; Silva,Arystides R.; Veloso,Carlos A. C.; Dantas,Edilândia F.; Sacramento,José A. A. S. do. |
| ABSTRACT Sustainable agricultural production systems can improve physical attributes of soil as well as increase carbon and nitrogen stocks in soils. The objective of this study was to evaluate changes in the stability of soil aggregates and contents and stocks of carbon and nitrogen after the conversion of native forest to crop-livestock-forest integration systems in the region of Western Pará. Soil samples from five management systems (including a control) were collected at three depths in a randomized block design, with five replications. The stability of the aggregates, soil density, particle density, and total soil porosity, as well as total carbon and nitrogen and their respective stocks were evaluated. The native forest had the highest percentages... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Organic carbon; Soil physics; Sustainability; Brazilian Amazon. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662018001200837 |
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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: Folhetos |
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; Pantanal; Acidity; Fractionation; Exchangeable cations; Organic matter; Nitrogen; Soil. |
| Ano: 2002 |
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/810747 |
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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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| Scheid,Douglas Leandro; Silva,Rodrigo Ferreira da; Silva,Vanderlei Rodrigues da; Ros,Clovis Orlando Da; Pinto,Marlo Adriano Bison; Gabriel,Márcia; Cherubin,Maurício Roberto. |
| ABSTRACT: Chemical and physical properties of soil can be altered with the successive application of liquid swine manure (LSM), also known as slurry. Therefore, monitoring the impact of LSM is essential to an assessment of the potential agronomic and environmental benefits and risks associated with management practices. The aim of this study was to evaluate the effects of LSM on the chemical and physical attributes of soil under pasture (Cynodon spp.), located in southern Brazil. Four areas were sampled: three areas cultivated with Cynodon spp. pasture with successive applications of 200 m3 ha–1 y–1 of LSM for three, eight and 15 years; and untreated native forest as a reference. The soil attributes evaluated were: organic carbon (OC), active (pH water)... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Management of organic residues; Organic carbon; Nutrient availability; Soil compaction; Soil chemistry. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162020000501401 |
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| Ochoa,Guido; Oballos,Jajaira; Velásquez,Juan Carlos; López,Isabel; Manrique,Jorge. |
| The majority (60 %) of the soils in the Venezuelan Andes are Inceptisols, a large percentage of which are classified as Dystrustepts by the US Soil Taxonomy, Second Edition of 1999. Some of these soils were classified as Humitropepts (high organic - C-OC-soils) and Dystropepts by the Soil Taxonomy prior to 1999, but no equivalent large group was created for high-OC soils in the new Ustepts suborder. Dystrusepts developed on different materials, relief and vegetation. Their properties are closely related with the parent material. Soils developed on transported deposits or sediments have darker and thicker A horizons, a slightly acid reaction, greater CEC and OC contents than upland slope soils. Based on the previous classification into large groups... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Classification; Inceptisols; Organic carbon. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832009000600026 |
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| Reis,Diony Alves; Lima,Cláudia Liane Rodrigues de; Bamberg,Adilson Luís; Ribeiro,Pablo Lacerda. |
| ABSTRACT: The southern Brazilian lowlands have been historically used for flooded rice cultivation. Over time, heavy machinery and intensive tillage practices have resulted in soil structure disruption, soil compaction, higher production costs and lower agricultural profitability. This study aimed to evaluate the effect of different deployment times of no-tillage (NT). Soil properties including bulk density (BD), compression index (CI), preconsolidation pressure (σp), bulk density at preconsolidation pressure (BDσp), degree of compactness (DC), soil water retention curve (SWRC), plant available water (PAW) and total organic carbon (TOC) content were evaluated using a 30-yr non-cultivated field (NC), adjacent to the experimental plots as a control. The BD,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Lowlands; Preconsolidation pressure; Degree of compactness; Organic carbon. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162018000500393 |
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| Andrade,Emilene; Miyazawa,Mário; Pavan,Marcos A.; Oliveira,Edson L. de. |
| The objective of this study was to re-evaluate some aspects of the relative importance of organic matter on Mn solubility in acid soil conditions. Field study showed that black oats, oil seed radish, elephant grass, lupin, leucaena, and coffee leaves serving as mulch decreased Mn solubility as compared with bare soil. The decrease in Mn solubility with plant mulch was related to increase in soil moisture content. Laboratory study showed that increasing temperature from 25 to 100ºC increased Mn solubility and total soil organic carbon was little changed; from 150 to 200ºC increased both Mn solubility and organic carbon oxidation, and up to 300ºC decreased Mn solubility and stoped organic carbon oxidation . Aluminum solubility always increased with... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Plant residue; Mulch; Organic carbon; Heavy metal; Micronutrient. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132002000100003 |
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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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| 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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| 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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| Costa,Silvio Teixeira da; Sutili,Fernando Jonas; Gressler,Luciane Tourem; Loebens,Luíza; Colpo,Carine Vargas; Lazzari,Rafael; Baldisserotto,Bernardo. |
| ABSTRACT: Humic substances are organic compounds that possess high molecular weight and are formed by the decomposition of plant materials. Humic substances comprise humic acids, fulvic acids and humin. Humic acids (HA) have shown to be able to provide some protection to biological membranes of fish in water with low pH, replacing the protective action of Ca2+. Thus, this studyaimed to observe growth of silver catfish ( Rhamdia quelen ) juveniles exposed to pHs 5.5 and 6.5 and to different levels of HA: 0, 10, 25 and 50mg L-1. Results showed that, irrespective of pH, HA was highly detrimental to silver catfish growth, since the higher the concentration of HA, the lower the weight gain and feed intake, resulting in lower biomass and lower specific growth... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Humic substance; Water pH; Fish growth; Organic carbon. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782016000601094 |
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| Fink,Jessé Rodrigo; Inda,Alberto Vasconcellos; Tiecher,Tales; Barrón,Vidal. |
| ABSTRACT Continuous crop expansion has led to a growing demand for phosphate fertilizers. A sound knowledge of the dynamics of phosphorus, and its interaction with iron oxides and organic matter, can be useful to develop effective strategies for sustainable management, especially in a scenario of increasing shortage of mineral phosphate resources. In this paper, we review the relationship of phosphate to iron oxides and organic matter, and its effect on phosphorus availability. Crops typically obtain phosphate from weathered minerals and dissolved fertilizers. However, the amount of phosphorus present in the soil solution depends on the extent to which it is adsorbed or desorbed by iron oxides, which may be influenced by interactions with organic matter.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Goethite; Hematite; Phosphorus adsorption; Phosphorus desorption; Organic carbon. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542016000400369 |
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| Registros recuperados: 41 | |
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