Performance Evaluation of a Portable Laser-Induced Fluorescence Spectroscopy System for the Assessment of the Humification Degree of the Soil Organic Matter

The importance of humin in soil characterisation: A study on Amazonian soils using different fluorescence techniques

“…When we apply the statistical analysis in these whole soil and HU fractions, we did not find a significant difference (p N 0.05). This behaviour for HU corroborates with Santos et al (2015), who reported an increase of humification with depth in some Amazonian soils. An explanation for this behaviour could be that the presence of aromatic polycondensation in the OM is also present in the corresponding horizon (Tivet et al, 2013).…”

“…The measurement range was from 420 nm to 800 nm, and the selected integration time and average were 500 ms and 4, respectively, for all measurements. Four replicates were recorded for each sample and the averaged spectrum was used (Santos et al, 2015). The humification index (H LIFS ) was determined by calculating the ratio between the area of the fluorescence emission spectrum (Ex: 465, Int from 450 to 700 nm) (ACF) and the amount of total organic carbon (in g kg −1 ) (TOC) present in the soil sample (Milori et al, 2006).…”

Soil organic matter in crop rotations under no-till

“…The soil MOC was obtained by the difference between TOC and POC. The degree of humification was determined by laser-induced fluorescence (H LIF ) (Milori et al, 2006;Santos et al, 2015). Samples were dried, homogenized, ground in a porcelain mortar, and sieved through 0.149-mm mesh.…”

Gênesis de espodossolos amazônicos: um estudo sobre a estrutura e a mobilidade da matéria orgânica

“…Página 64 intensidade máxima de 525-550 nm, com ombros de ambos os lados, e são semelhantes aos relatados na literatura para MOS (Senesi et al, 1991;Milori et al, 2002;Tivet et al, 2013;Santos et al, 2015) conforme observado na Figura 5.I.11. Essa região de comprimentos de onda de 525-550 nm sugere a presença relevante de componentes moleculares caracterizados por uma estrutura aromática resistente de policondensado com um elevado grau de conjugação e podem transportar substituintes, como grupos carbonilas e carboxílicos.…”

“…Os espectros LIFS foram registados em pastilhas, contendo 0,5 g de amostra de solo seco ou de humina, mediante a aplicação de um laser de onda contínua em 405 nm, com potência de 20 mW e resolução de 10 nm, utilizando um equipamento portátil (Santos et al 2015 …”