EN
The aim of the research was to compare the effects of four to quaternary ammonium salts (QAS) with iodine anion: tetramethylammonium iodine [TMA][I], tetraethylammonium iodine [TEA][I], tetrapropylammonium iodine [TEA][I], tetrabutylammonium iodine [TBA][I]. The experiment was carried out on sandy clay loam samples with organic carbon content of 33.82 g·kg⁻¹, and pH in 1 M KCl 7.13. QAS were added to soil at the dosages of: 0, 10, 100, and 1000 mg·kg⁻¹. Activity of dehydrogenases was assayed on days: 1, 14, 35, and 70. Obtained results have shown that the soil treatment with quaternary ammonium salts with iodine anion caused decrease in activity of dehydrogenases. This inhibition increased with increase of QAS dosages, and increase with alkyl chains in cations. Analysis of variance η² indicated, that type of QAS had the biggest impact on formation of activity of dehydrogenases in soil.