Biochar for sustainable soil and environment: a comprehensive review

Biochar prepared from organic waste through pyrolysis, thermal combustion in an inert environment, generates a stable form of carbon. The review of established literature reveals that conversion of organic matter into biochar and its addition to soil also reduces the negative effects of carbon aerosols on human health and greenhouse gas effects on environment through carbon sequestration. Physicochemical properties of biochar such as nutrient sorption capacity, pH, pore structure, particle size, surface area, and mineral content play a vital role in determining the soil structure and function. Biochar addition to soil exerts measurable changes in physicochemical soil properties such as bulk density, water-holding capacity, pH and cation exchange capacity, microbial community structure, and their interrelated functions in soil. However, addition of biochar to specific soil improves the soil fertility, and consequently improves the crop yield. It is concluded that optimized pyrolysis of organic waste for biochar production and its use for soils need diversified investigation in diverse environmental conditions.