The chemical properties of biochar, soil and biochar-amended soil were determined by standard methods. The pH was measured potentiometrically in 1 M KCl after 24 h in the liquid/soil ratio of 10. The cation exchange capacity (CEC) and available potassium, phosphorus and magnesium were determined according to procedures for soil analysis (van Reeuwijk, 1992). Total organic carbon (TOC) was determined by TOC-VCSH (SHIMADZU) with Solid Sample Module SSM-5000. The total nitrogen (Nt) was determined by the Kjeldahl's method without the application of Dewarda's alloy (Cu–Al–Zn alloy-reducer of nitrites and nitrates)