Carbon stock of tree biomass, litter and soil in rubber based agroforestry systems

Abstract

Agroforestry systems (AFSs) that have rubber tree as the main tree component are important productive systems in the Brazilian Amazon. This work aimed to evaluate carbon stock (CS) of tree biomass, litter and soil in rubber based AFSs in South-Western Amazon. The analytical observational study was carried out in Rolim de Moura (RO) from June 2018 to March 2019 and it consisted of five areas: three AFSs, a forest fragment (FL), and a pasture (PA). CS of tree biomass was determined using allometric equations, while litter and soil carbon stocks were performed through material collection and chemical analysis. Total carbon stock of AFS 1, AFS 2, and AFS 3 was 181.36, 165.77, and 99.08 Mg ha^-1, and soil was the compartment that most contributed to the EC of these systems, with stocks of 108.06, 88.71, and 72.68 Mg ha^-1, respectively. Total stock of FL was 188.02 Mg ha^-1 and PA was 88.19 Mg ha^-1. The older AFSs, with greater floristic richness, greater basal area and with the presence of cupuassu tree as a secondary crop had total carbon stock similar to the forest area, evidencing the potential of these systems to sequester atmospheric CO₂.