Dynamics of litterfall in agroforestry systems with cocoa trees and natural forest in Eastern Amazon

Litter dynamics is a key component in the soil-plant relationship in forest ecossistems, espacially in agroforestry systems. Accumulated on the forest floor, the litter layer regulates the soil temperature and moisture, the nutrient cycling and the organic carbon stock of the soil. This study aimed to evaluate the decomposition rate, annual deposition, and accumulation of litter in agroforestry systems (AFS) of different ages, based on cocoa, compared to a natural forest in the eastern Amazon. The study was conducted in Tomé-Açu, Pará. In each area (AFSs and forest), 10 plots of 900 m² were set up to quantify the litter deposited and accumulated in AFSs of different ages (21, 22, and 23 years). The areas differed significantly from each other in terms of litter deposition, decomposition and stock (p < 0.001). The natural forest showed higher deposition and higher decomposition rate, while systems with less decomposition showed higher litter accumulation, showing differences in the dynamics of organic matter cycling between the systems. It can be concluded that cocoa-based agroforestry systems have a capacity to supply litter comparable to that of natural forests, ensuring a continuous flow of residues to the soil. As this litter decomposes, these systems promote the release and return of organic carbon, contributing to the maintenance of carbon stocks and the biogeochemical sustainability of the soil.