The dehydrogenase activity is considered to be an indicator
of the oxidative metabolism in soils and thus of the microbial
activity (microbial redox system and oxidative activities) (Trevors,
1984). However, the relationship between an individual biochemical
property and the total microbial activity is not always obvious,
especially in the case of complex systems like soils, where the
microorganisms and processes involved in the degradation of the
organic compounds are highly diverse (Nannipieri et al., 1990). Soil
ureases are one of the most important enzymes involved in soil
organic matter mineralization, they release N–NH4
+ through urea
hydrolysis and are essential in the chain of hydrolysis of amino
compounds, which are supplied to the soil from plants and to a
lesser extent from animals and microorganisms. In addition, this
enzyme is part of microbial products that can be accumulated in
cell free forms because they are highly resistant to environmental
degradation (Zantua and Bremner, 1977).