3.1. Properties of cavitated charcoal and soils
The cavitated charcoal (CHAR-C) used in the study had an alkaline pH and high electrical conductivity (EC). The content of macronutrients, e.g., calcium and potassium, varied in the studied material (Table 1). The content of heavy metals was lower than that observed in biochar produced from plant biomass (Gondek et al., 2017). The LS and C soils used in the study had different granulometric compositions and chemical properties (Table 2). Both soils were characterised by the natural content of heavy metals examined in this study.