Comparison of the composition of forest soil litter derived from three different sites at various decompositional stages using FTIR spectroscopy

摘要

Transmission Fourier transformed infrared spectroscopy was used to compare organic soil layers originating from three different sites in two climatic regions. A variety of bands characteristic of molecular structures and functional groups have beenidentified for these samples from a humic Podzol, a dystric Cambisol and a spodo-dystric Cambisol. Similar results were obtained for all three soils. From L to H soil horizons, an increase of the band at 1630 cm-1 and decrease of bands in the region from1510 to 1230 cm-1 were observed. The band at 1630 cm-1 can be assigned to carboxylic and aromatic groups. The decline of the peak intensity at 1510 cm-1 is significantly correlated to the total carbon content and C:N ratio. The mineral material of the Ah horizons leads to an increase of the band at 1050 cm-1 due to IR-absorbance of the Si-O bond and to an appearance of bands in the region from 900 to 400 cm-1, which are characteristic for clay and quartz minerals. Analysis of the FTIR absorbance showedthat intensities of distinct peaks (e.g. at 1510 cm-1) can be a measure of decomposition of forest litter. Therefore, the proposed simple FTIR method has potential for identification and differentiation of organic soil horizons originating from known tree litter. The similarity of the characteristics of the spectra of the three soil profiles investigated suggests a broad applicability of this method to distinguish organic forest soil horizons. On the basis of the data presented in this study, it is concluded that FTIR spectroscopy offers a simple, powerful, non-destructive tool for the investigation of decomposition of L to H horizons in forest soils.