Evaluating the dynamics of carbon accumulation in extensive argan orchard ecosystems in arid regions

Abstract Background Extensively cultivated argan orchards in Argan Biosphere Reserve in Morocco, aged 2–10 years, were assessed to quantify ecosystem components (above-ground argan biomass, leaf litter, herbaceous vegetation, and soil) and their carbon stocks. The study was conducted in six sites over two years, from 2021 to 2023. Each site included two plots for investigation. Morphophysiological characteristics and dendrometric parameters were measured, and structural equation modeling was applied to elucidate the complex interactions among the orchard components. Argan plant biomass and soil physicochemical properties were determined. The carbon stock of each component was calculated using the 2019 Refinement to 2006 IPCC guidelines. Results The carbon stock in total argan plant biomass ranged from 0.003 t C ha -1 in 2-year-old plants to 1.938 t C ha -1 in 10-year-old plants. The carbon stock associated with leaf litter ranged from 0.36 to 8.51 kg C ha -1 . Herbaceous-grass biomass carbon stock ranged from 0 to 0.56 t C ha -1 . The total soil organic carbon (SOC) stock varied significantly, from 10.12 to 80.5 t C ha -1 at a depth of 0–30 cm and from 8.49 to 75.94 t C ha -1 at a depth of 30–60 cm, and was identified as the dominant carbon reservoir. Conclusions These findings provide a comprehensive analysis of carbon sequestration dynamics in arganiculture ecosystems under extensive management while supporting ecosystem rehabilitation within the Argan Biosphere Reserve. They position arganiculture as a viable component of Morocco’s Nationally Determined Contributions, aiding in carbon market integration. These findings also offer insights into the sequestration potential of similar plantations in arid regions.