EN
The influence of long-term mineral, organic and organic plus mineral fertilization in total, on the properties of humic acids from the black earth, was studied. Mineral fertilization caused the decreased absorption, specific of the phenol and alcohol OH groups, C=C and C=O bounds in aromatic compounds and NH of 1st order amins. Fertilization with the manure affected the increase absorption in the field of the frequency, specific of the groups: -CH3, -OCH3, -CH2 and -COOH. Fertilization with the use of half of the dose of manure and NPK caused the increase absorption by -COOH groups. Mineral and organic fertilization increased the amount of amino acids in KH, and of amino- and total nitrogen. The manure fertilization combined with the mineral fertilization had the opposite effect. The greater share of aromatic compounds was stated in KH from the soil, fertilized with a half of the dose of manure and NPK, the lowest one was found in KH from the soil fertilized only with NPK. On the other hand, the degree of condensation of aromatic compounds was the highest in KH from the soil, fertilized with the manure and the lowest one was stated in KH from the soil fertilized with a half of the dose of manure and NPK.