Bitumens isolated from the individual soil horizons of the cambisol sa
mples in Boubin-north spruce stand (Sumava Mts.) were analysed using d
iffuse-reflectance IR spectroscopy (DRIFTS). DRIFTS is suitable as a s
emiquantitative method for the detection of composition changes of soi
l bitumens with the increasing soil depth. The aromaticity of soil bit
umens decreases, aliphatic chains elongate, and ratio of polar fractio
n decreases with the increasing depth.