Assessment of the effects of environmental factors on humification processes by derivative infrared spectroscopy and discriminant analysis

Mid-infrared spectroscopy for topsoil layer identification according to litter type and decompositional stage demonstrated on a large sample set of Austrian forest soils

“…factors for discriminant analyses, leading to convincing separations of the involved groups by second derivatives of infrared bands. For humic acids, the diagnostic infrared bands chosen were at 1720, 1260 and 1330 cm − 1 ; aliphatic and aromatic bands were not significantly responsive to environmental variability (Fernández-Getino et al, 2010). These interesting results complement the outcome of the present study, suggesting that both humic acids and bulk soils reflect site characteristics, but by different signals of mid-infrared spectra.…”

“…Our results identifying aliphatic characteristics as important for discriminating different soil layers according to decompositional stage and litter type are in line with the literature discussed above. Fernández-Getino et al (2010) recently published a study in which humic acids were isolated from 21 soil samples differing in vegetation, geological substrate, soil type, soil horizon, humus type, physiographic unit, altitudinal step, epipedon and moisture regime. These site properties were used as environmental classification Table 4 Coefficients of the calculated discriminant functions for the identification of forest soil layers (Fig.…”

“…While these effects presented obstacles for the determination of inorganic and organic carbon contents in the previous work of Tatzber et al (2010), they are expected to offer opportunities for the discrimination between soil samples from sites with defined site characteristics. Fernández-Getino et al (2010) used mid-infrared signals from humic acids together with discriminant analysis to investigate influences of environmental factors (vegetation, geological substrate, etc.) on humification processes in Mediterranean forest soils from Central Spain.…”

“…With this methodology it was possible to differ between soil suborders and humus types and also between several physiographic and bioclimatic features. Further it was possible to identify diagnostic infrared bands which were chosen automatically by the variable backward selection when calculating the discriminant function (Fernández-Getino et al, 2010). Consequently, mid-infrared spectroscopy together with calculated discriminant functions may offer a possibility to differentiate soil layers according to defined site characteristics and forest type also in bulk soil samples.…”

Soil Chemical Insights Provided through Vibrational Spectroscopy

“…With manure vs straw treatment, and crop diversification and land cover (rotation vs. monoculture vs. fallow), general aromatic and carbonyl content decreased, with specific decreases in benzene and methyl absorbances, whereas amide bands and sulfone and/or ester absorbance increased (Ohno et al, 2009;Tatzber et al, 2009) (C-H) at 873-728 cm −1 , and sp 3 -CH 2 and mono-/di-substituted benzene rings at 766 cm −1 . FTIR of HS is also sensitive to climate, vegetation cover, and geologic features, allowing discrimination of HA by soil suborder level and humus type (Fernández-Getino et al, 2010).…”