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| Registros recuperados: 42 | |
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| Barros,Alexandre Hugo Cezar; Lier,Quirijn de Jong van; Maia,Aline de Holanda Nunes; Scarpare,Fábio Vale. |
| Pedotransfer functions (PTF) were developed to estimate the parameters (α, n, θr and θs) of the van Genuchten model (1980) to describe soil water retention curves. The data came from various sources, mainly from studies conducted by universities in Northeast Brazil, by the Brazilian Agricultural Research Corporation (Embrapa) and by a corporation for the development of the São Francisco and Parnaíba river basins (Codevasf), totaling 786 retention curves, which were divided into two data sets: 85 % for the development of PTFs, and 15 % for testing and validation, considered independent data. Aside from the development of general PTFs for all soils together, specific PTFs were developed for the soil classes Ultisols, Oxisols, Entisols, and Alfisols by... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Soil water retention curve; Tropical soils. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832013000200009 |
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| Armindo,Robson André; van Lier,Quirijn de Jong; Turek,Maria Eliza; Reis,Aline Mari Huf dos; Melo,Marina Luciana Abreu de; Ramos,Maria Elisa Palma; Ono,Gabriela Massame. |
| ABSTRACT The soil water retention curve (SWRC) is essential for vadose zone hydrological modeling and related applications. In 2004, Groenevelt and Grant (GRT) presented a mathematical model for describing the SWRC and reported its mathematical versatility and good fit to soils from a Dutch database. In order to evaluate the application of GRT to SWRCs of Brazilian soils, we aimed to analyze the performance of GRT for 72 soils from Brazil. Besides that, the obtained results with GRT for these soils were compared to the fitting performance of the most frequently used models: Brooks and Corey (BC) and van Genuchten-Mualem (VGM). The three models were fitted to available soil water retention data by minimizing the sum of square errors. The Pearson correlation... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Tropical soils; Hydraulic properties; Mathematical models. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832019000100407 |
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| Santos,Hemmannuella C.; Oliveira,Fábio H. T. de; Souza,Adailson P. de; Salcedo,Ignácio H.; Silva,Valério D. M.. |
| ABSTRACT Phosphorus (P) availability is related to soil sorption capacity and is relevant to planning P fertilization and evaluating its residual effect. The aim of this work was to evaluate the P availability to maize plants after different incubation times of six soils from Paraíba state. For this, four doses of P (0, 100, 200 and 300 mg dm-3) were applied in samples of six soils for 0, 30, 60, 90, 180, 240 and 360 days. After the incubation time, the soil samples received fertilization with macro and micronutrients and were cultivated with maize for 35 days, when they were harvested and analyzed to verify dry matter and P content in soil. The increase in the time of contact of P with the soil decreased P availability to plants; however, the formation of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Residual effect; Phosphate; Tropical soils. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662016001100996 |
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| Sakuno,Natanael Rodolfo Ribeiro; Guiçardi,Augusto Cesar Ferreira; Spalevic,Velibor; Avanzi,Junior Cesar; Silva,Marx Leandro Naves; Mincato,Ronaldo Luiz. |
| ABSTRACT The water erosion process has a considerable negative effect on tropical soils, causes soil losses from arable land and reduces the capacity to support surrounding ecosystems. Estimating soil losses caused by water erosion is fundamental for evaluating the impacts of various production systems. Therefore, improving soil loss estimates via the adaptation of models for different edaphoclimatic environments is necessary for estimating local geographic and climatic differences. This study aimed to adapt, apply and evaluate the potentialities of the Potential Erosion Method for Latosols of the Hydrographic Subbasin of Caçús Stream, southern Minas Gerais State. Geological, topographic, pedological, climatic and land use and occupation data were... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Modeling of water erosion; RUSLE; Tropical soils. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902020000100409 |
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| Razafimbelo,Tantely; Chevallier,Tiphaine; Albrecht,Alain; Chapuis-Lardy,Lydie; Rakotondrasolo,Fela Nirina; Michellon,Roger; Rabeharisoa,Lilia; Bernoux,Martial. |
| Soil organic carbon (SOC) is usually said to be well correlated with soil texture and soil aggregation. These relations generally suggest a physical and physicochemical protection of SOC within soil aggregates and on soil fine particles, respectively. Because there are few experimental evidences of these relations on tropical soils, we tested the relations of soil variables (SOC and soil aggregate contents, and soil texture) with the amount of SOC physically protected in aggregates on a set of 15 Malagasy soils. The soil texture, the SOC and water stable macroaggregate (MA) contents and the amount of SOC physically protected inside aggregates, calculated as the difference of C mineralized by crushed and intact aggregates, were characterized. The relation... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Macroaggregate; Tropical soils; Soil structure; Carbon stabilization. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162013000300009 |
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| Gmach,Maria Regina; Cherubin,Maurício Roberto; Kaiser,Klaus; Cerri,Carlos Eduardo Pellegrino. |
| ABSTRACT: In tropical regions, climate conditions favor fast decomposition of soil organic matter (SOM), releasing into the soil organic composts in solid, liquid, and gaseous forms with variable compositions. Dissolved organic matter (DOM), a complex mixture of thousands of organic compounds, is only a small fraction of the decomposition products; however, it is highly mobile and reactive to the soil. Therefore, DOM play a key role in soil aggregation (formation of organometallic complexes), energy source for microorganisms, as well as C storage, cycling, and provision of plant-available nutrients. DOM multifunctionality to sustain soil functions and important ecosystem services have raised global scientific interest in studies on DOM fractions. However,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Brazil; Dissolved organic carbon; Agricultural soils; Tropical soils. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162020000301800 |
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| Mellis,Estêvão Vicari; Cruz,Mara Cristina Pessôa da; Casagrande,José Carlos. |
| There is little information on nickel adsorption by Brazilian soils. The objective of this experiment was to determine the effect of pH, organic matter, and iron oxides on nickel adsorption by three soils: a clayey Anionic "Rhodic" Acrudox, a sandy clay loam Anionic "Xanthic" Acrudox, and a clayey Rhodic Hapludalf. Soil samples were collected from the 0-0.2 m layer and treated to eliminate organic matter and iron oxides. The nickel adsorption was evaluated in the original samples and in those treated to remove organic matter and to remove both, organic matter and iron oxides, using 2 g soil + 20 mL of 0.01 mol L-1 CaCl2 solution containing 5 mg L-1 Ni, pH varying from 3.5 to 7.5. The nickel adsorption decreased with the elimination of organic matter. For... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Ni adsorption; Tropical soils. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162004000200011 |
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| Alleoni,Luís Reynaldo Ferracciú; Camargo,Otávio Antonio de; Valadares,José Maria Aires Silva. |
| Relationship between soluble boron extracted with a hot CaCl2 0.01 mol L-1 solution and pH; organic carbon; exchangeable cations; cation exchange capacity (CEC); base saturation; total, free and amorphous iron and aluminum oxide contents; clay content; and specific surface area were performed for surface and subsurface samples of five soils. The soils were a Rhodic Hapludox, an Arenic Paleudalf and three Typic Hapludox, all representative soils of the State of São Paulo, Brazil. To quantify the relations between soluble boron and the different soil characteristics, simple linear correlations and multiple regressions, using a stepwise regression program, were performed. Hot-CaCl2 extractable boron (HCB) was significantly correlated with clay content (r =... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Soluble boron; Tropical soils; Simple correlation; Multiple regression analysis. |
| Ano: 1999 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90161999000200006 |
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| Maione,Camila; Araujo,Eloá Moura; Santos-Araujo,Sabrina Novaes dos; Boim,Alexys Giorgia Friol; Barbosa,Rommel Melgaço; Alleoni,Luís Reynaldo Ferracciú. |
| ABSTRACT Lettuce (Lactuca sativa) is the main leafy vegetable produced in Brazil. Since its production is widespread all over the country, lettuce traceability and quality assurance is hampered. In this study, we propose a new method to identify the geographical origin of Brazilian lettuce. The method uses a powerful data mining technique called support vector machines (SVM) applied to elemental composition and soil properties of samples analyzed. We investigated lettuce produced in São Paulo and Pernambuco, two states in the southeastern and northeastern regions in Brazil, respectively. We investigated efficiency of the SVM model by comparing its results with those achieved by traditional linear discriminant analysis (LDA). The SVM models outperformed the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: ICP–OES; Traceability; Tropical soils; Heavy metals; Feature selection. |
| Ano: 2022 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162022000100901 |
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| Sombroek,Wim. |
| Thirteen main landform units are distinguished for the whole of the forested Amazon region, each with its specific soil pattern and vegetation structure. These landform-soil-vegetation units are delineated on a small-scale map and illustrated by a schematic cross-section. Floristic diversity of the gamma type is to be highest on the steepland-and-valley complexes of the Andean fringe, on the crystalline shield uplands, on the inselberg complexes, and on the eutric variant of the western sedimentary plains. Endemism is expected to be highest on the sandy plains, and parts of the table lands and inselberg complexes. Speciation, linked to the concept of forest refuge areas, is likely to be highest on the sandstone table lands, on the stretches of Amazon... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Amazon; Major landforms; Tropical soils; Floristic biodiversity. |
| Ano: 2000 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0044-59672000000100081 |
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| Guerra, Naiara; Universidade Estadual de Maringá-UEM; Oliveira Júnior, Rubem Silvério de; Universidade Estadual de Maringá - UEM; Constantin, Jamil; Universidade Estadual de Maringá - UEM; Oliveira Neto, Antonio Mendes de; Universidade Estadual de Maringá - UEM; Dan, Hugo de Almeida; Universidade Estadual de Maringá - UEM; Braz, Guilherme Braga Pereira; Universidade Estadual de Maringá - UEM. |
| Scarce research has been published concerning the effect of soil pH on the leaching potential of herbicides in tropical soils. Thus, we designed this study to evaluate the influence of soil liming on the leaching of trifloxysulfuron-sodium and pyrithiobac-sodium after simulated rainfall depths in soil columns. In the study, two trials were conducted simultaneously; the first experiment evaluated trifloxysulfuron-sodium (7.5 g ha-1), while the second experiment evaluated pyrithiobac-sodium (70 g ha-1). Both experiments were conducted in a randomized block design with a 2 x 4 x 5 factorial scheme and four replications. The design’s factors corresponded to 2 soil liming conditions (with or without liming), 4 simulated rainfall depths (0, 15, 30, and 45 mm)... |
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Palavras-chave: ALS inhibitors; Mobility; Soil pH; Tropical soils. |
| Ano: 2013 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/16349 |
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| Bourotte,Christine; Forti,Maria Cristina; Lucas,Yves; Melfi,Adolpho J.. |
| Studies about pollution by Polycyclic Aromatic Hydrocarbons (PAHs) in tropical soils and Brazil are scarce. A study was performed to examine the PAHs composition, concentrations and sources in red-yellow Oxisols of remnant Atlantic Forest of the São Paulo State. Sampling areas were located in an urban site (PEFI) and in a natural one (CUNHA).The granulometric composition, pH, organic matter content and mineralogical composition were determined in samples of superficial soils. The sum of PAHs (ΣHPAs) was 4.5 times higher in the urban area than in the natural one. Acenaphthylene, acenaphthene, fluorene, phenanthrene and fluoranthene have been detected in the soils of both areas and presented similar concentrations. Acenaphthene and fluorene were the most... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Atlantic Forest; Polycyclic aromatic hydrocarbons; PAHs; Tropical forest; Tropical soils; Urban soils. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652009000100013 |
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| Registros recuperados: 42 | |
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