Researchers revisited a 14-year field trial in Bolivia. They measured biomass and soil organic carbon (SOC) across five cocoa systems. These included conventional and organic monocultures, conventional and organic agroforestry, and successional agroforestry (SA). Biomass carbon rose in every system between 2011 and 2022. By 2022, agroforestry systems had more than doubled the biomass carbon found in monocultures. SA reached 66.2 t C/ha. OA reached 55.4 t C/ha. CA reached 52.8 t C/ha. Both monocultures stayed near 26 t C/ha.
Cacao trees alone stored more carbon in monocultures than in agroforestry. But shade trees made up the difference. They contributed 60–72% of total biomass carbon in the agroforestry systems. SOC stocks told a different story. Total SOC (0–50 cm) did not differ significantly between systems in 2010 or 2020. Still, topsoil carbon rose more in agroforestry than in monocultures. CA and SA both showed significant topsoil SOC increases between 2010 and 2020.
Organic management had no significant effect on either biomass or SOC stocks. This held true across all comparisons. By 2022, combined biomass and soil carbon peaked in SA at 135 t C/ha. OA followed at 132 t C/ha. CA reached 113 t C/ha. Monocultures trailed behind, at 103 t C/ha (organic) and 83 t C/ha (conventional).
