Because of its high organic C content

Because of its high organic C content, biochar has the potential
to serve as a soil conditioner to improve the physicochemical and biological properties of soils. Soil water retention capacity in- creases with increase in organic C. About 18% increase in the water holding capacity of soil containing biochar was reported (Glaser et al., 2002). Soil water holding capacity is related to hydrophobic- ity and surface area of biochar, and the improved soil structure fol- lowing biochar application (Verheijen et al., 2010). A decrease of nutrient leaching due to biochar application has been also reported (Sohi et al., 2009). Biochar generally has a neutral to alkaline pH; however, acidic biochar has been also reported (Chan et al., 2007). The pH of biochar depends on various factors including feedstock type and the thermochemical process of production. The alkaline pH of biochar induces a liming effect on acidic soils, thereby possibly increasing plant productivity. The extent of liming effect of biochar depends on its acid neutralizing capacity that var- ies depending on the feedstock and pyrolysis temperature. For example, biochar derived from paper mill waste pyrolyzed at 550 ?C had a liming value around 30% that of CaCO3 (Zweiten et al., 2010). Significant