Agricultural Horizons: Research, Technology and Sustainable Development Vol. 3

Biochar is increasingly framed as a climate-smart agricultural amendment because it can combine durable carbon storage with changes in soil fertility, water relations, nutrient losses and greenhouse-gas emissions. Yet the field has moved beyond the premise that a generic carbon-rich material will deliver uniform benefits. This critical narrative review examines the emerging transition towards “Biochar 2.0”: purpose-designed biochars whose feedstocks, pyrolysis conditions, post-production treatments, nutrient loading, mineral associations and placement are selected for defined soil–crop functions. Literature published from 2010 to 4 July 2026 was critically synthesised, with earlier conceptual material considered only where necessary. The evidence indicates that material properties are strongly controlled by feedstock and thermal history, while ageing and organic coating can alter nutrient retention after soil incorporation. Across meta-analyses, microbial biomass responds more consistently than microbial diversity, and links between community shifts and agronomic function remain less certain than is often implied. Nitrogen- and phosphorus-use benefits are clearest when biochar is integrated with fertiliser management, co-composting or nutrient enrichment rather than applied as an isolated substitute for fertility inputs. Greenhouse-gas mitigation is also conditional: nitrous oxide reductions are reproducible on average but smaller and more variable in field-focused syntheses than in earlier laboratory-heavy evidence, while methane responses in rice systems depend strongly on nitrogen management. Carbon-dioxide fluxes must be distinguished from whole-system carbon removal. The central argument is therefore not that increasingly modified biochars are intrinsically superior, but that climate-smart value depends on matching a characterised product to a defined soil constraint, crop system, nutrient regime and life-cycle boundary. Research priorities include multi-year factorial field trials, process-rate measurements coupled to multi-omics, harmonised material reporting, external validation of predictive models, contaminant and ecotoxicological surveillance, and farm-scale economic and life-cycle assessment. Biochar 2.0 is most defensible as a precision-deployment framework rather than a universal technology class.