2.2.2. Physical and chemical characterisation
Kuwagaki (1990) proposed that seven properties should be measured for a quality
assessment for agronomically-used biochar: pH, volatile compound content, ash content,
water holding capacity, bulk density, pore volume, and specific surface area.
Feedstock is a primary factor governing the chemical and physical properties of biochar. The
elemental composition reported for a range of bio-oil and biochar products from various
feedstocks are compared in Table 2.