Biochar for soil applications-sustainability aspects, challenges and future prospects

Biochar has recently proven to be effective in various applications including soil amendment for crop production and removal of pollutants from the contaminated water and soil environments. However, major studies on the alterations in bulk density, porosity, water holding capacity, acidity and mineral content of the soils due to the addition of biochar have been carried out in lab-scales. Innumerable studies have investigated the properties of the biochar prepared from various feedstocks under various pyrolysis conditions to examine the effect of peak operating temperature, heating rate and residence time. To promote the commercialization of biochar for large-scale applications, there is a need for critical discussion on the advantages and disadvantages of the biochar for various soil applications (e.g., soil amendment and/or decontamination) in terms of technical, environmental, economic and social considerations. To address this urgent need, the present review attempts to evaluate the application of biochar for soil amendment within the framework of sustainability and recommendations for the future research and applications of biochar for soil treatment.