Prospective assessment of the carbon footprint of cashew production in the Brazilian semiarid based on carbon dynamics modeling

Context Prospecting the carbon footprint (CF) of production systems is essential for guiding sustainable decision-making in fruit orchards. However, few assessments of fruit cropping systems integrate soil organic carbon (SOC) dynamics throughout the entire orchard lifespan, particularly of novel non-monoculture experimental systems. Objective This study innovates by combining SOC modeling for orchard lifespan and biomass carbon measurements with CF assessment in cashew production, enabling a prospective analysis of the sustainability of cashew cropping systems in the Brazilian semiarid region. Methods Five cashew production systems were evaluated, encompassing orchards aged 6 to 13 years in experimental (E) and commercial (C) areas. The CF of 1 kg of cashew products (nuts and apples) was assessed according to ISO 14067. To estimate carbon accumulation over the production cycle, cashew trees were assumed to have a lifespan of 25 years, and biomass carbon stocks were quantified from the seedling stage to adult trees. Greenhouse gas emissions were estimated using the ICVCalc tool, while SOC stocks in the 0–20 cm layer were simulated using the RothC model for different orchard ages. A sensitivity analysis examined orchard scenarios with varying lifespans,land transformation, fertilization practices, and planting density. Results and Conclusions Results showed biomass carbon increased from 0.0014 to 27.63 Mg ha −1 over the years, allowing the development of a cashew-specific allometric equation. The assessment of three experimental (E1–E3) and two commercial (C1 and C2) cashew production systems revealed that the highest predicted SOC stock occurred in the system intercropped with forage (E3), whereas the lowest was found in the commercial monoculture. Likewise, the lowest carbon footprint (0.051 kg CO₂ eq kg −1 ) was observed in the E3 system. The sensitivity analysis indicated a reduction in the carbon footprint with an extended orchard lifespan, complete replacement of mineral fertilizers with organic fertilizers applied efficiently, planting density of 100 plants ha -1 , and land use transformation from maize to dwarf cashew. Significance The integration of SOC and biomass carbon modeling with CF assessment proved effective for forward-looking projections, underscoring the potential of diversified systems to meet sustainability certification criteria and support climate change mitigation.