Decoupling Biomass and Soil Carbon: Agroforestry Typologies in Côte d’Ivoire Cocoa Farms

Côte d’Ivoire, the world’s largest cocoa producer, supplies more than 40% of global cocoa. Recent shifts in shade tree density, species composition, and pruning- driven by sustainability and farm renewal initiatives- raise questions about their effects on soil organic carbon (SOC) and carbon allocation. We assessed carbon stocks across 90 cocoa farms in western and central Côte d’Ivoire using multivariate clustering based on SOC and aboveground biomass (AGB) from cocoa and shade trees.

Four distinct farm typologies emerged with contrasting carbon allocation patterns. High SOC / Moderate AGB systems (12% of farms) stored the greatest SOC (139 Mg C ha⁻¹) despite moderate biomass, indicating SOC-efficient systems that allocate a larger share of carbon belowground. In contrast, Moderate SOC / Very High AGB systems (14%) were shade-dominated, with extremely high biomass (220 Mg ha⁻¹) but moderate SOC (56 Mg C ha⁻¹), reflecting SOC-inefficient systems where carbon is concentrated aboveground. The remaining farms were classified as Low SOC / Moderate AGB (21%) and Low SOC / Low AGB (52%), characteristic of simplified or degraded systems.

SOC and AGB were weakly correlated (r < 0.10), indicating a decoupling between tree biomass and soil carbon accumulation. Although total ecosystem carbon stocks were similar in SOC-efficient (175 Mg C ha⁻¹) and high-biomass systems, carbon partitioning differed markedly. SOC accumulation depends on system structure not biomass alone. Management strategies focused solely on increasing shade tree density risk overestimating soil carbon gains, underscoring the need to promote SOC-efficient agroforestry systems for climate-smart cocoa production.