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| Silveira,Maria Lucia Azevedo; Alleoni,Luís Reynaldo Ferracciú. |
| Cu adsorption, at concentrations between 0 to 800 mg L-1, was evaluated in surface and subsurface samples of three Brazilian soils: a heavy clayey-textured Rhodic Hapludalf (RH), a heavy clayey-textured Anionic ''Rhodic'' Acrudox (RA) and a medium-textured Anionic ''Xanthic'' Acrudox (XA). After adsorption, two consecutive extractions were performed to the samples which received 100 mg L-1 copper. Surface samples adsorbed higher amounts of Cu than the subsurface, and exhibited lower Cu removed after the extractions, reinforcing the influence of the organic matter in the reactions. Cu adsorption was significant in the subsurface horizons of the Oxisols, despite the positive balance of charge, demonstrating the existence of mechanisms for specific... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Adsorption; Isotherms; Desorption; Tropical soil. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132003000400006 |
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| Silveira,Maria Lucia Azevedo. |
| Soil quality has become an important issue in soil science. Considerable attempts have been made to define soil quality, but a general concept has not yet been accepted by the scientific community. The selection of quantitative indices for soil quality is extremely difficult, and a considerable number of chemical, physical, and biochemical properties have been suggested as potential indicators of soil quality. Because soil organic matter (SOM) can be associated with different soil chemical, physical and biological processes, it has been widely considered as one of the best soil quality indicator. Land use can significantly influence dynamics of organic carbon and N, P, and S cycle. However, changes in total soil organic carbon (SOC) contents in response to... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Ecosystem management; Sustainability; Indicators of soil quality. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162005000500017 |
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| Silveira,Maria Lucia Azevedo; Alleoni,Luís Reynaldo Ferracciú; Casagrande,José Carlos; Camargo,Otávio Antônio. |
| Estudou-se a energia livre da reação de adsorção de cobre em amostras superficiais (0-0,2 m) e subsuperficiais (na maior expressão do horizonte B) de três solos paulistas : Latossolo Roxo ácrico (LR), Latossolo variação Una ácrico (LU) e Terra Roxa Estruturada (TE), após a adição de 5, 20, 50, 100, 200, 300, 400 e 600 mg L-1 de cobre. A adsorção de cobre pelos solos foi considerada espontânea, pois a energia livre apresentou valores negativos em todas as concentrações estudadas. Os valores de energia livre diminuíram com o aumento da dose de cobre adicionada. A TE apresentou maior energia livre de adsorção em relação aos Latossolos, sobretudo em superfície. Considerando-se o mesmo solo, os horizontes superficiais apresentaram maior energia livre para as... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Latossolo ácrico; Cobre; Adsorção; Energia livre. |
| Ano: 1999 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90161999000500013 |
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