A review of biochar's sustainability in climate-smart agriculture: Recent advances, emerging trends, and future directions

Climate change and soil degradation threaten global agriculture, necessitating sustainable solutions. This study adopted a dual methodological approach, integrating a systematic review with quantitative bibliometric analysis to evaluate the potential of biochar in climate-smart agriculture. A total of 180 documents published between 2010 and 2023 were retrieved from the Scopus database. Using the Bibliometrix R package, the study conducted trend analysis, country-level publication metrics, keyword co-occurrence analysis, thematic mapping, and thematic evolution. In parallel, a systematic review guided by PRISMA protocols synthesized findings from 80 peer-reviewed articles. The bibliometric analysis showed that China contributed 18 % of publications, followed by India (13 %) and Pakistan (6 %). Thematic mapping identified biochar as a "motor theme" (a well-developed and central topic within the research field) closely associated with climate-smart agriculture. The study revealed biochar's multiple benefits: enhancing soil fertility, increasing crop yields (up to 340 % for potatoes), and sequestering carbon with a potential to mitigate 2.56 × 109 tons of CO_2-eq/year, representing about 4.7 % of global annual greenhouse gas emissions in 2023. However, economic feasibility and long-term consequences, such as potential shifts in soil microbiota and nutrient cycling dynamics over decades, continue to pose challenges. The study highlights biochar's promise in addressing climate change and promoting sustainable agriculture while stressing the need for long-term field studies, mechanistic research, and transdisciplinary approaches for successful implementation. Policy incentives such as carbon credits, subsidized biochar production technology, and integrated agricultural extension programs could accelerate biochar adoption in smallholder systems.