Researchers compared four cacao systems in Bolivia. These included conventional and organic monocultures, and conventional and organic agroforestry. They measured carbon stocks, litterfall, and pruning residues over seven years. By 2015, agroforestry systems held far more aboveground carbon than monocultures. Agroforestry reached 26 Mg C/ha. Monocultures reached only 7–8 Mg C/ha. Shade trees drove this gap. They contributed up to 47% of total carbon in agroforestry plots.
Cacao trees themselves told a different story. They grew faster in monocultures than in agroforestry. By 2015, cacao biomass in monocultures exceeded that in agroforestry by 1.5 times. Shade and competition likely slowed cacao growth in the mixed systems.
Litterfall followed tree density. Agroforestry systems produced significantly more litter carbon than monocultures. Management type—organic or conventional—made no difference here. Pruning residues added even more carbon than litterfall. Residues contributed over twice as much carbon as litterfall across all systems. Erythrina shade trees drove most of this input in agroforestry plots.
Nitrogen flows favored agroforestry too. Pruning residues delivered up to 10 times more nitrogen than synthetic fertilizer application. Leguminous shade trees supplied roughly half of this nitrogen input in agroforestry systems. Organic and conventional management showed no significant difference in total carbon storage. This held true across both monoculture and agroforestry systems.
