ANNUAL DYNAMICS OF ORGANIC-MATTER AND BASIC NUTRIENTS IN SEDIMENTS OF2 HYDROMELIORATION CHANNELS IN THE EASTERN SLOVAKIA LOWLANDS

Sediments from the 4 sites of 2 hydromelioration channels in the Easte rn Slovakia lowlands were monitored. Results showed the difference in both the amount and qualitative structure of their organic matter cont ents. High organic matter concentrations with increased share of resis tant matter due to imperfect degradation contributed to an increased h umus production. During mineralization of the most unstable fraction o f organic matter the concentration of ammonium nitrogen predominated o ver that of nitrate-nitrogen, thus indicating a higher rate of denitri fication compared to nitrification. Changes in the amount of phosphori c compounds were more dependent on the release rate of organic and ino rganic fraction from organic matter than on their content. The Ca2+, M g2+, Na+ and K+ cations dynamics is related to the organic matter mine ralization, or to the presence of macro-vegetation during its growth.