Comparative field‐scale assessment of TLUD and Kon‐Tiki biochar systems: agronomic performance and net CO 2 e‐based techno‐economics

Abstract Post‐harvest agricultural residues in Latin America are commonly underutilized, leading to greenhouse gas emissions and lost opportunities for bio‐based value creation. This study tests the hypothesis that decentralized, farmer‐scale pyrolysis technologies can deliver comparable agronomic benefits while exhibiting distinct techno‐economic and climate performance under field conditions. Two biochar production technologies, top‐lit up‐draft (TLUD) and Kon‐Tiki kilns were evaluated using corn cob residues as soil‐amending bioproducts at a 1%(w/w) application rate. Both biochars were non‐phytotoxic, exhibiting radish germination rates above 90% and no inhibition of radicle elongation. The TLUD biochar developed 21% higher microporosity than Kon‐Tiki, indicating enhanced surface functionality for soil–plant interactions. Field application significantly improved soil properties relative to the control, increasing pH by 1.9 units, electrical conductivity by 1.8‐fold, organic matter by 1.3‐fold, and cation exchange capacity by 1.6‐fold. These changes resulted in higher plant nutrient uptake, with foliar potassium and phosphorus concentrations increasing by 1.3‐ and 1.7‐fold, respectively. The TLUD‐derived biochar consistently outperformed Kon‐Tiki in nutrient delivery, consistent with its higher surface area and fixed‐carbon content. Integrating agronomic outcomes with net CO 2 e‐based techno‐economic performance reveals trade‐offs between biochar quality, nutrient delivery, capital requirements, and climate benefits that cannot be inferred from laboratory‐scale experiments. Techno‐economic analysis showed that both technologies generate positive net CO 2 e benefits in situ , with TLUD requiring lower initial investment (>900€ less than Kon‐Tiki), while both systems converge in profitability after the first production cycle. These findings demonstrate that integrated field‐scale assessment is essential to identify decentralized biochar systems that are agronomically effective, economically viable, and climate relevant.