3.2. Soil pH dynamics during the incubation period
Soil pH decreased with increasing incubating duration for
biochar treatments during the first few days (Fig. 3). Soil pH in PBV
and PBS increased after approximately 20 days (descending
inflection points) and then remained constant after some 40 days,
whereas soil pH in PBA already increased after approximately 5
days. Small fluctuations in CKV and CKS trends were observed. The
addition of biochars to soil increased overall pH and the increase
was higher for the fresh biochar (Table 3). After 1 day or at the end
of incubation, soil pH values in biochar–soil treatments were
significantly higher (P 0.05). At the end of the incubation, soil pH levels of PBV and PBS
increased by 0.250.03 and 0.240.04 units, respectively.