2.6. Determination of soil properties and enzymatic activities
Prior to soil physical and chemical analyses, all samples were air-dried at room temperature and passed through a 2-mm soil sieve. Soil pH was measured with combined electrodes in a 1:2.5 soil to water suspension; available nitrogen was estimated via the alkaline KMNO4method (Prasad, 1965). Soil organic matter was determined as described previously (Janzen, Bole, Biederbeck, & Slinkard, 1990).
The activities of urease, peroxidase, and phenol oxidase were determined as described in Saiyacork (Saiyacork, Sinsabaugh, & Zak, 2002). Catalase activity was measured following the method of Dai et al. (Dai et al., 2017).