Effects of municipal solid waste compost and sewage sludge on chemical and spectroscopic properties of humic acids from a sandy Haplic Podzol and a clay loam Calcic Vertisol in Portugal

Spectral characterization of selected humic substances

“…The long wavelength and large fluorescence intensity of the major peak of SH may be ascribed to the presence of an extended, linearly-condensed aromatic ring network, and other unsaturated bond systems capable of a great degree of conjugation in large molecular size and extensively humified "macromolecules". On the contrary, the prevalence of fluorescence bands and peaks with high relative intensity at short wavelengths, such as those measured for the peak of LH, is associated with the presence of simple structural components of wide molecular heterogeneity and small molecular weight, small degree of aromatic condensation, small level of conjugated fluorophores, and small humification degree (Mobed et al 1996;Chen et al 2003;Pedra et al 2008;Fernández et al 2009). The main molecular components that contribute to fluorescence in this range of excitation/emission wavelength may be chromone derivates (excitation/ emission wavelength pair 320-346/409-490 nm) and flavones and isoflavones (excitation/emission wavelength pair 313-365/415-475 nm) (Senesi et al 1991;Pedra et al 2008).…”

“…The long wavelength for the fluorescence peaks of SH indicate the presence of condensed aromatic ring and other unsaturated bond systems, a high degree of conjugation, and electron-withdrawing groups such carbonyl and carboxyl groups. The short wavelength of the main fluorescence peak of the sample LH suggest the presence of simple structural components of wide molecular heterogeneity and small molecular size, low degree of aromatic polycondensation, low level of conjugated fluorophores, and low humification degree (Senesi 1990;Pedra et al 2008). The fluorescence excitation spectra of SH and LH are shown in Figure 2.…”

“…Excitation spectra were recorded over the range of 300-480 nm at a fixed emission wavelength of 520 nm. Synchronousscan excitation spectra were measured by simultaneously scanning both the excitation and the emission wavelength (from 200 to 600 nm), while maintaining a constant, optimized wavelength difference ∆λ = λ em -λ ex = 20 nm, and for LH ∆λ = 60 (Senesi et al 1996;Plaza et al 2006;Pedra et al 2008). The Total Luminescence (TL) spectra were obtained in the form of excitation/emission matrix (EEM) by scanning the wavelength emission over the range of 300-600 nm, also the excitation wavelength was in 5 nm steps from 300 to 600 nm (Alberts & Takács 2004;Palazzo et al 2008;Fernández et al 2009).…”

Effect of Vermicompost Extract and Vermicompost-Derived Humic Acids on Seed Germination and Seedling Growth of Hemp

“…It seems that it is important to discriminate between effects of preparations containing humic substances made from "dead" organic sources (coal, leonardite, peat) vs. humic substances isolated from organic materials containing living microorganisms (biological waste, compost, vermicompost), as both chemical properties and biological activity are variable (Campitelli and Ceppi, 2008;Pedra et al, 2008). Humic substance-containing preparations from biological waste potentially could have higher biological activity (Xu et al, 2012).…”

Quantity and Quality of Organic Matter in Soil after Application of Various Organic Materials/Ilość I Jakość Materii Organicznej W Glebie Po Aplikacji Różnych Materiałów Organicznych

“…Increasing value of absorbance ratio 4/6 may evidence a marked decrease in the degree of humic acids particles or greater aliphatisation and higher number of functional groups [4]. Also Pedra et al [21], using compost produced from municipal wastes and anaerobically stabilized sludge for fertilization, demonstrated an increase in the value of absorbance coefficient A4/6, associating the changes of the discussed parameter with diminishing the condensation degree of humic acid particles and greater aliphatisation. Results of research published by Aranda et al [22] indicate greater changes of organic matter quality concerning aromatization of humic acids.…”