ИСТИНА

The authors give a quantitative characterization of lignin phenols in soils and in particle-size fractions of grey forest soils (Russian Plane) and soils of the North Caucasus. Most of lignin phenols oxidation products (50 %) are associated with the coarse sand (>250 µm) fraction. However, in silty fractions (< 2 µm, 2-20 µm) there is a maximum of oxidation level and degree of transformation of the side chains of the lignin. The possible influence of soil mineralogical composition on the specific surface area of soil aggregates and on possible adsorption of lignin phenols is shown. Fe-Mn-concretions of all sizes contain the lignin of higher plants.