Iron and aluminum forms and their relationship with texture, mineralogy and organic carbon in the Cerrado Oxisol

• Autor(a) principal: Vendrame, Pedro Rodolfo Siqueira
• Data de Publicação: 2011
• Outros Autores: Eberhardt, Diogo Néia, Brito, Osmar Rodrigues, Marchão, Robélio Lenadro, Quantin, Cécile, Becquer, Thierry
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Semina. Ciências Agrárias (Online)
• Texto Completo: https://ojs.uel.br/revistas/uel/index.php/semagrarias/article/view/3477
• topic: Sequential extractions Iron and aluminium oxides; Crystallinity; Oxisols.; Extrações seqüenciais; Óxidos de ferro e alumínio; Cristalinidade; Latossolos.

The Oxisols of the Cerrado region have a simple mineralogy, and are composed mainly of kaolinite and iron and aluminium oxides. The aim of this work was to perform a sequential extraction of iron and aluminium and to relate them to texture, mineralogy and organic carbon in Oxisols of the Cerrado region. The soil samples, 35 in total, were taken from the 0–20 cm layer in Oxisols under pasture located in the Brazilian Cerrado Region. The levels of iron and aluminum extracted by full attack, dithionite-citrate-bicarbonate, ammonium oxalate and sodium pyrophosphate were analyzed according to the textural classes using the Kruskal-Wallis nonparametric test. Then these data were related to the mineralogy and organic carbon through a principal component analysis. Whatever the textures, iron oxides of high degree of crystallinity were the main form of iron and are positively correlated with the iron total content. The aluminum oxides have a high affinity to organic carbon than iron oxides. The levels of iron and aluminum extracted by sodium pyrophosphate were closely related to soil pH.