Com. enzymic prepn. was added to slurry and used in winter rape and spring wheat cultivation. The activity of urease, dehydrogenase and phosphatase was studied in a 2-year field exp. (2011-2013). The increase in the activity of urease, dehydrogenase and phosphatase depended on applied fertilization, cultivated plant species and soil sampling time. The activities increased from 4.33 to 15.3%, from 6.11 to 24.3% and from 9.78 to 10.7%, resp., when compared to the object with mineral fertilization.