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| Registros recuperados: 41 | |
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| Fink, Jessé Rodrigo; Universidade Federal do Rio Grande do Sul; Inda, Alberto Vasconcellos; Universidade Federal do Rio Grande do Sul; Bayer, Cimélio; Universidade Federal do Rio Grande do Sul; Torrent, José; Universidade de Córdoba; Barrón, Vidal; Universidade de Córdoba. |
| The low phosphorus availability in tropical and subtropical soils, normally related to adsorption of phosphate to the minerals surfaces, can be attenuated when organic matter (OM) accumulates in the soils. Herein, we report the results of long-term experiments (18–32 years) aimed at quantifying the maximum phosphorus adsorption capacity (MPAC) and its determinant mineralogical variables in Brazilian soils and at assessing the effect of no-tillage (NT) in mitigating the phosphorus adsorption of soils. The MPAC of soils ranged from 297 to 4,561 mg kg-1 in the 0.00–0.10 m layer and from 285 to 4,961 mg kg-1 in the 0.10–0.20 m layer. The MPAC was correlated with the concentrations of iron oxides, goethite and ferrihydrite, gibbsite/(gibbsite+kaolinite) ratio... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: 5.01.01.00-5; 5.01.01.05-6; 5.01.01.01-3 iron oxides; Gibbsite; Organic carbon; Phosphate Fertilidade do solo; Gênese do solo; Manejo do solo. |
| Ano: 2014 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/17937 |
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| Loureiro,Diego Campana; De-Polli,Helvécio; Ceddia,Marcos Bacis; Aquino,Adriana Maria de. |
| The objective of this work was to study the spatial variability of soil microbial biomass (SMB) and labile soil organic matter pools (labile SOM), under different management systems and plant cover. The experiment was conducted in a Haplic Planosol soil on an Integrated Agroecological Production System (SIPA), in Seropédica, Rio de Janeiro. The evaluated management systems were: alley cropping, pasture, and bush garden, the late one was used as reference area. Three grids of regular spacing of 2.5 x 2.5 meters were used for sampling, consisting of 25 georeferenced points each, where soil samples were taken at 0-10 cm depth. The following labile constituents of soil organic matter were determined: free light fraction (FLF), water soluble C and N, C and N of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Organic carbon; Geoestatistic; Glomalin; Precision agriculture. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052010000500010 |
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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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| 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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| Lara,Nelson; Figueroa,Leonardo; Carvajal,Fabiola; Zapata,Yubinza; Urbina,Camilo; Escobar,Hugo. |
| N. Lara, L. Figueroa, F. Carvajal, Y. Zapata, C. Urbina, and H. Escobar. 2013. Quantitative differentiation between soil organic carbon and biochar carbon in Aridisol. Cien. Inv. Agr. 40(2): 387-395. To understand the effect of biochar, identify its presence and quantify its stability in soil, it is necessary to differentiate between the two main sources of carbon. These sources are resident soil organic matter and biochar, which is produced by burning organic matter under low oxygen concentration in a process known as pyrolysis. The present study employs solid-liquid extraction with an alkaline solution, the efficiency of which was improved by a reflux system and quantification using the modified Walkley-Black method, to distinguish the two carbon sources... |
| Tipo: Journal article |
Palavras-chave: Alkaline extraction; Differentiate; Humic acid; Organic carbon. |
| Ano: 2013 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-16202013000200013 |
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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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| 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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| 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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| 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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| 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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| Registros recuperados: 41 | |
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