Data/hora: 22/06/2024 07:18:06

Biblioteca(s): | Embrapa Instrumentação.
Data corrente: | 12/08/2004
Data da última atualização: | 11/09/2007
Autoria: | LEITE, F. de L.; CUNHA, T. J. F. da; MARTIN-NETO, L.; MADARI, B.; SANTOS, G. A.; MATTOSO, L. H. C.; HERRMANN, P. S. de P.
Título: | Study of amazon antropogenic humic acid by Atomic Force Microscopy (AFM).
Ano de publicação: | 2004
Fonte/Imprenta: | In: MARTIN-NETO, L.; MILORI, D.M.B.P.; SILVA, W.T.L. (Ed.). Humic substances and soil and water environment: International Meeting of IHSS, 12. São Carlos : Embrapa Instrumentação Agropecuária, 2004. p. 318-320.
Idioma: | Inglês
Notas: | CLASSIFICAÇÃO CDD: 630

Conteúdo:

I. INTRODUCTION 
Soil Organic Matter (SOM) play important rule on many aspects of the nature of soil and environmental processes. Humic Substances (HS) are the major organic constituents of soils and aquatic environments and are generated by the microbiological and chemical degradation and transformation of organic matter resulting in chemical structures which are more stable than the starting material (Steverson, 1982). Various studies in the Brazilian Amazon mention the existence of soils having an anthropogenic A horizon (Cunha et al., 2001). These soils, ofien referred to as Amazonian dark earth (or "Terra Preta"), present particular physical and chemical properties. The organic matter present in these soil show high stability and reactivity characteristics (Glaser et al., 2000). The origin of this organic matter is thought to be mostly pyrogenic and is in relation to the domestic/agricultural activity of pre-Columbian populations that colonized the Amazon basin since 3000 B.C. (Denevan, 2001). Because of its high fertility compared to the adjacent soils, it is has been frequently used by
recent populations of lhe Amazon for subsistence agriculture (beans, corn etc.) and/or for production for market sale of a high diversity of products (papaya, coconut, cupuaçu etc.). Since, a better understanding of HS structures would help to determine their origin and genesis reactivity, and role in environmental processes, lhe objective this work was to study lhe Humic Acid (HA) with selected methods in the compared to an adjacent soil that did not have anthropogeni  A horizon, using an Atomic Force Microscope (AFM). The purpose of our investigation was to obtain a better understanding of morphology, adsorption and orientation of HA molecules on mica from anthropogenic HA. This microscope can image surfaces with atomic resolution by scanning a sharp tip across the surface at forces smaller than the forces between atoms (Leite et al., 2003). AFM is a scanning probe technique, which has been employed to study the morphologies of humic and fulvic (Plaschke et al., 2002, 1999; Mertig et al., 1999) and it is a powerful tool to characterize small colloids, as well as colloid agglomeration, adsorption onto surfaces, or modification in the morphologies affected by changes in the physical-chemistry properties.

Palavras-Chave: | Amazon; anthropogenic soils; Humic acid.
Thesaurus Nal: | atomic force microscopy.
Categoria do assunto: | --
Registro original: | Embrapa Instrumentação (CNPDIA)
Exemplares: | CNPDIA - (8326-1) - UMT - SP - -- - PROCI-04.00004 -  - 2004.00004 - DIS