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All publications of “Uidemar Morais Barral”

4 results

Chemical-Mineralogical Characterization of Magnetic Materials from Magnetic Soils of the Southern Espinhaço Mountain Chain and of the Upper Jequitinhonha Valley, State of Minas Gerais, Brazil

Alexandre Christófaro Silva, Solange de Souza, José Domingos Fabris, Maurício Soares Barbosa, Uidemar Morais Barral, Roberto Vial Costa


ABSTRACT In the Southern Espinhaço Mountain Chain and in the Upper Jequitinhonha Valley, magnetic soils, in different pedogenetic stages, are found to be forming over intrusions of basic lithology. The essential chemical and mineralogical properties of samples from magnetic soil profiles from those two physiographic environments in the state of Minas Gerais, Brazil, are reported. Three of the pedons (Rhodic Kandiustox – RKox, Rhodic Haplustox – RHox, and Typic Argiustoll – TAoll) were identified as being indeed developed over basic […]

Surface mapping, organic matter and water stocks in peatlands of the Serra do Espinhaço meridional – Brazil

Márcio Luiz da Silva, Alexandre Christófaro Silva, Bárbara Pereira Christófaro Silva, Uidemar Morais Barral, Pablo Gomes e Souza Soares, Pablo Vidal-Torrado


Peatlands are soil environments that store carbon and large amounts of water, due to their composition (90 % water), low hydraulic conductivity and a sponge-like behavior. It is estimated that peat bogs cover approximately 4.2 % of the Earth’s surface and stock 28.4 % of the soil carbon of the planet. Approximately 612 000 ha of peatlands have been mapped in Brazil, but the peat bogs in the Serra do Espinhaço Meridional (SdEM) were not included. The objective of this […]

Lignocellulosic and isotopic composition of vegetation and soil organic matter of a tropical peat. I floristic composition, biomass and carbon stock

Vinicius Evangelista Silva, Alexandre Christofaro Silva, Rosana Cristina Pereira, Plínio Barbosa de Camargo, Bárbara Pereira Christofaro Silva, Uidemar Morais Barral, [...]


Soil organic matter (SOM) is one of the major reservoirs of carbon on Earth and is one of the key contributors to the carbon cycle. Peatlands are natural accumulators of organic matter commonly derived from decomposing plant residues in water-saturated environments, and represent an initial stage of a much longer pedogenic pathway leading to carbonification. The soil biomass markedly influences the global carbon cycle, accounting for approximately 85 % of all carbon on the Earth’s surface. Plant tissues are mainly […]

Lignocellulosic and isotopic composition of vegetation and soil organic matter of a tropical peat. II humic substances and humification processes

Alexandre Christofaro Silva, Vinicius Evangelista Silva, Bárbara Pereira Christofaro Silva, Plínio Barbosa de Camargo, Rosana Cristina Pereira, Uidemar Morais Barral, [...]


Much of the organic matter of a typical peat consists of humic substances, mainly formed via humification of organic residues, decomposed by soil microorganisms, and by the polymerization of organic compounds to functional macromolecules, which are normally more resistant to degradation. The fundamental pathways governing the humification of soil organic matter (SOM) are not well understood so far, and most available data about the identified chemical precursors of humic substances and the main chemical routes by which they are transformed […]