EN
Twenty different soils were investigated. The soils varied in their acidification degree, granulometric composition and a carbon content. The investigated soils were collected from arable land, meadows and forests. Humic compounds were extracted from the soil according to the Konowowa and Bielczikova's method. Very high quantitative and qualitative differentiation\was observed. It was related to the soil type and utilisation system. Low but differentiated quantities of humic compounds extracted by 0.05 M H2SO4 were found in the samples of the analysed soils. In the extract of pyrophosphate and sodium base as well as in the extract of sodium base, there were more fulvic acids than humic acids which was reflected in the narrow Ckh:Ckf ratio, particularly in the forest soils. In addition very high proportion of non-hydrolysing carbon was observed. Its content ranged from 52 to 84%. The highest proportion of this fraction was found in the soils agriculturally utilised.