COMPARISON OF THE COMPOSITION OF FOREST SOIL LITTER DERIVED FROM 3 DIFFERENT SITES AT VARIOUS DECOMPOSITIONAL STAGES USING FTIR SPECTROSCOPY

Transmission Fourier transformed infrared spectroscopy was used to com pare organic soil layers originating from three different sites in two climatic regions. A variety of bands characteristic of molecular stru ctures and functional groups have been identified for these samples fr om a humic podsol, a dystric cambisol and a spodo dystric cambisol. Si milar results were obtained for all three soils. From L to H soil hori zons, an increase of the band at 1630 cm(-1) and decrease of bands in the region from 1510 cm(-1) to 1230 cm(-1) were observed. The band at 1630 cm(-1) can be assigned to carboxylic and aromatic groups. The dec line 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 regi on from 900 to 400 cm(-1), which are characteristic for clay and quart z minerals. Analysis of the FTIR absorbance showed that intensities of distinct peaks (e.g., at 1510 cm(-1)) can be a measure of decompositi on of forest Litter. Therefore, the proposed simple FTIR method has po tential for identification and differentiation of organic soil horizon s originating from known tree litter. The similarity of the characteri stics of the spectra of the three soil profiles investigated suggests a broad applicability of this method to distinguish organic forest soi l horizons. On the basis of the data presented in this study, it may b e concluded that FTIR spectroscopy offers a simple, powerful, non-dest ructive tool for the investigation of decomposition of L to H horizons in forest soils. (C) 1998 Elsevier Science B.V.