Weathering of biochar: implications to soil health, carbon sequestration and soil remediation

There has been increasing interest in the application of biochar as a soil amendment to sequester carbon and remediate contamination. The novelty of this review is that it provides thorough bibliometric analysis and critical discussions on various processes of biochar weathering, factors affecting the weathering processes, and the implication of biochar weathering on its potential value for carbon sequestration and soil remediation in relation to promoting soil health. Although biochar contains stabilized carbon, when exposed in the field, biochar undergoes physical, chemical, and biological weathering processes, which could lead to fragmentation of biochar, impacting its nature, characteristics, and reactivity. The weathering of biochar in soil is impacted by the nature of biochar, soil type, cultivation practices, and environmental conditions. This review will advance the existing knowledge on how weathering-initiated changes in biochar alter the interactions between biochar and soil components significantly, including microorganisms. Therefore, this article will provide core perspectives on how these events impact carbon sequestration, contaminant remobilization, soil health, and soil remediation potentials of biochar.