The main subject of our work was to evaluate the effects of applied organic fertilizers: farmyard manure, sewage sludges of various origin and the sludge-peat mixture on changes in the available magnesium and zinc content of two soils with different texture tested in an incubation experiment. Results of our experiment revealed that the contents of magnesium depended on the source and rate of fertilization whereas intensity of changes related with this element transformations was depending on the soil deposit. Zinc content was more dependent on soil properties than on the amounts of fertilization applied.
