Agricultural byproducts converted to biochar to enhance soil functionality through sustainable innovation

Agricultural by-products or residues remain in the soil and are considered a burden unless properly managed. Traditionally, agricultural by-products and agro-food industry-derived waste streams are managed through composting or incineration, but these methods fail to unlock the wastes full potential. Thus, a promising yet unexplored research area for sustainable management of agricultural waste needs to be investigated. Under these circumstances, this review paper positions the conversion of these wastes into biochar (BC). It provides a comprehensive analysis of recent advances and critical limitations in the application of BC, particularly derived from agricultural by-products, for sustainable use in agricultural soils. BC, a carbon-rich product obtained from the pyrolysis of organic materials, has gained significant attention due to its potential to improve enhance soil health by improving soil fertility while, simultaneously sequestering carbon, thereby contributing to sustainable agriculture and climate change mitigation. However, the widespread adoption of BC has notable challenges. This paper elaborates current research on the production of BC from various agricultural residues, examining its physicochemical properties (e.g., surface area, porosity, pH, etc.) and influencing soil amendment processes. The focus is on how effective BC is in enhancing soil fertility, water retention, and microbial activity, along with its role in reducing soil acidity and heavy metal and organic contamination. A critical evaluation of the limitations in current research, including variability in BC characteristics, uncertainties in long-term effects, and challenges in large-scale application, is presented. The paper also explores the economic and environmental aspects of BC application in agriculture, addressing the balance between cost-effectiveness and environmental sustainability. Additionally, the paper discusses the policy and regulatory framework surrounding BC application, highlighting the need for standardized guidelines to maximize its benefits. This review emphasizes the necessity for multidisciplinary research approaches to optimize BC use in agricultural soils, ensuring both agricultural productivity and environmental sustainability.