Data/hora: 06/06/2024 22:21:12

Biblioteca(s): | Embrapa Instrumentação.
Data corrente: | 13/08/2004
Data da última atualização: | 08/03/2010
Autoria: | MILORI, D. M. B. P.; GALETI, H. V. A.; MARTIN-NETO, L.; BAYER, C.; SALTON, J.; GONZÁLES-PÉREZ, M.
Título: | Humification degree of organic matter in whole soil determined by laser-induced fluorescence.
Ano de publicação: | 2004
Fonte/Imprenta: | In: INTERNATIONAL MEETING OF INTERNATIONAL HUMIC SUBSTANCES SOCIETY. -- IHSS, 12, São Pedro, SP, 2004. Humic substances and soil and water environment. Abstracts...[São Carlos], SP: Embrapa Instrumentação Agropecuária, 2004. p. 61.
Idioma: | Inglês

Conteúdo:

I. INTRODUCTION 
The soil organic matter (SOM) is an impórtanl carbon reservoir. Its plays the main role in the soil productivity because it serves as nutrients source for the plants (i.e. N, P, K), influences the soil pH, the anion and cation exchange capacity, and its physical structure. The increase of humificalion degree of SOM can occur due to the changes in soil regimes, decrease of annual C inputs by crops, and exposition of physically protected SOM into soil agreggates under conventional tillage. 
Despite the great importance of the humification degree of SOM in agricultural systems, many techniques have been used to evaluate this parameter. C13 Nuclear Magnetic Resonance spectroscopy (NMR) is used to evaluate aromaticity degree of humic acid (HA) extracted from SOM and it supplies information of some chemical transformations which occurred during the decomposition and humification processes of SOM. Anolher technique, that also can be used in the humificalion study of the SOM is Electronic Paramagnetic Resonance spectroscopy (EPR). It gives credit to lhe fact that complex aromatic structures stabilize semiquinone-type free radicais (Senesi, 1990), and thus, its concentration, that can be determined by the EPR, correIates with the humification degree of SOM (Martin-Neto el al., 1998). EPR as well as NMR, are important techniques used 10 study structure and humification degree of SOM, however they have limitations when applied whole soils or HA extracled from soil wilh high paramagnetic metal concentration. 
Recently, fluorescence spectroscopy has been recognized as a useful technique to study chemical structure of environmenlal samples such as soil HA. Its potential to evaluale humification degree and molecular size of humic substances in solulion was algo demonstrated by some researchers (Zsolnay et al., 1999; Kalbitz et al., 1999; Milori el al., 2002). 
This paper intends to show some results of organic matter analysis obtained for whole soil using laser-induced fluorescence (LlF) spectroscopy. The application of this technique in whole soil samples is an innovation and lhe obtained results indicate the high polential of this methodology. This technique is interesting because it allows the soil analysis in conditions near to its natural slale avoiding physical and chemical fraclionation processes of humic substances; second, it allows, algo, the insoluble fraction analysis of the organic matter (humine); moreover it is suitable even in conditions where the attainmenl of signals for EPR and NMR is very difficult, as for example, in soil wilh high paramagnetic metal concentration, as is lhe case of lhe Oxisols, so common in the Brazilian territory.

Palavras-Chave: | Ácido húmico; fluorescence spectroscopy; Humidificação; humification degree; laser; RMN.
Thesagro: | Radiação; Solo Orgânico.
Thesaurus Nal: | soil organic matter.
Categoria do assunto: | --
Registro original: | Embrapa Instrumentação (CNPDIA)

Exemplares:

CNPDIA - (8333-1) - UMT - SP - -- - PROCI-04.00011 -  - 2004.00011 - DIS
CNPDIA - (8567-1) - UMT - SP - -- - PROCI-04.00064 -  - 2004.00064 - DIS