Mitigation of soil salinity using biochar derived from lignocellulosic biomass

Abstract

Soil salinisation is recognised as a serious form of soil degradation, affecting crop production and compromising food security. It is crucial to remediate the negative impacts of soil salinisation to improve the associated soil functions. Various organic and inorganic amendments are used for saline soil remediation. Biochar, known as the porous solid carbonaceous material produced at elevated temperatures ranging from 300 °C to 1,000 °C under oxygen deficit condition, is gaining considerable attention. Biochar is widely reported to enhance the sorption of nutrients and reduce nutrient leaching from the soil. Biochar application is effective in improving the physical, chemical and biological properties of saline soil. Limited studies were reported on the role of biochar to mitigate soil salinity, especially in terms of their adsorption mechanisms. This paper review the various role of biochar, derived through the pyrolysis of fibrous biomass, to improve the physical properties (soil porosity, soil aggregation, water holding capacity, hydraulic conductivity and organic carbon content) and chemical properties (pH, electrical conductivity, exchangeable sodium percentage and sodium adsorption ratio) of saline soil. Physical adsorption and ion exchange are found to be the most common remediation mechanisms of saline soil by biochar.