*2.3. Methodology of Biochemical Analyses*

The activities of dehydrogenases (EC 1.1), catalase (EC 1.11.1.6), alkaline phosphatase (EC 3.1.3.1), acid phosphatase (EC 3.1.3.2), arylsulfatase (EC 3.1.6.1), β-glucosidase (EC 3.2.1.21), and urease (EC 3.5.1.5) were determined in triplicate in individual soil samples from the cultivation of each plant species studied. A detailed procedure of enzymatic activity determination is provided by Borowik et al. [50] and Borowik et al. [13]. The substrates used to determine the enzymatic activity included aqueous solutions of the following chemical compounds: 2,3,5-triphenyl tetrazolium chloride (TTC) for dehydrogenases, urea for urease, disodium 4-nitrophenyl phosphate hexahydrate (PNP) for phosphatases, potassium-4-nitrophenylsulfate (PNS) for arylsulfatase, and 4-nitrophenyl-β-D-glucopyranoside (PNG) for β-glucosidase. The activities of all enzymes except for catalase were determined by measuring the reaction product extinction using a Perkin-Elmer Lambda 25 spectrophotometer (Massachusetts, USA). Catalase activity was analyzed with the titration method. The activity of dehydrogenases was expressed in μmol TFF (tri-fenylformazane), that of catalase in mol O2, that of alkaline phosphatase, acid phosphatase, arylsulfatase, and β-glucosidase in mmol PN (p-nitrophenol), and that of urease in mmol N-NH4 kg−<sup>1</sup> soil d.m. h<sup>−</sup>1.
