We researched the ordinary chernozems under cultivation, in the wooded park and in the downtown under the asphalt (so-called ekranozem). Optical density and Humic Acid’s extinction coefficients of investigated soils are within the normal parameters for the chernozem zone. The most significant changes were noted in Humic Acids (HA) molecules of wooded park’s chernozem. It has the lowest values of the HA’s optical density and the highest value of the E4:E6 ratio that indicates an increased amount of lateral radicals in HA molecules. The infra-red spectrums of the investigated HA are characterized by the high intensity of carboxyl groups’ absorption bands and distinct display of benzenoid structures’ bands. The wooded park’s chernozem contains HA with increased share of OH-groups (alcohols, possible phenols), CH-groups (paraffin chains), and nitrogen-containing groups. That features identify this particular HA as enriched with peripheral aliphatic chains. The IR spectrum of HA extracted from ekranozem is very similar to the spectral analysis of arable chernozem’s HA, but the results suggest fewer amount of COOH-groups in ekranozem’s Humic Acid.
