Impact of cacao-based agroforestry systems carbon storage in above-ground biomass and necromass in the Colombian Amazon

Abstract Cacao-based agroforestry systems (cAFS) represent a sustainable land use that enhances carbon storage in aboveground biomass, particularly in degraded pasture areas of the Amazon. This study estimated carbon storage across different land use systems in the Colombian Amazon, including cAFS, full-sun cocoa plantations, forests, and degraded pastures. Measurements included aboveground biomass (cocoa trees and shade canopy) and necromass, constituted by litter and dead wood, using a randomized complete block design with five replications. Aboveground carbon storage varied significantly among land uses ( P < 0.05). Forests exhibited the highest carbon storage (83.2 Mg C ha⁻ 1 ), with most carbon stored in trees (85.8%), followed by leaf litter (6.8%) and dead wood (4.4%). Dead wood, in the form of fallen logs and standing deadwood, contributed 4.4% and 2.8%, respectively, to carbon storage. Pastures had the lowest carbon storage (0.9 Mg C ha⁻ 1 ); whereas carbon storage in cAFS averaged 14.5 Mg C ha⁻ 1 , with 28% of that stored in cacao trees (4.2–6.0 Mg C ha⁻ 1 ). Shade canopy trees contributed 17% to carbon storage, ranging from 2 to 35% (0.4–6.6 Mg C ha⁻ 1 ). Accompanying trees and leaf litter stored an additional 13% and 11%, respectively. Although full-sun cocoa plantations were less effective than cAFS in storing carbon, they showed potential for carbon sequestration compared to degraded pastures. This study highlights the potential of cAFS to restore degraded lands and contribute to carbon storage, emphasizing its role in mitigating climate change and promoting sustainable land management in the Amazon.