SOIL CARBON MANAGEMENT INDEX IN OIL PALM CULTIVATED IN AGROFORESTRY AND MONOCULTURE SYSTEMS
soil organic matter, labile fraction, soil quality
Agroforestry systems are considered alternatives for conventional palm oil production, aiming at the provision of environmental services such as carbon sequestration and soil quality. The objective of this study was to determine and evaluate the magnitude and dynamics of soil carbon fractions under agroforestry systems based on oil palm and monoculture, comparing to a secondary forest, in order to verify the sustainability of these ecosystems. The experiment was conducted in the city of Tomé-Açu, Pará, in three demonstration units (UDI, UDII and UDIII) of the SAF-Dendê Project: Innovation and sustainability. In each system, five random plots were determined, in which four collection points were established: carrier (CAR), oil palm base (BD), stacking (P) and SAF range. The amounts of Oxidizable Carbon per KMnO4 (C-POX) were evaluated and the contents of Total Carbon (CT) in elemental analyzer by means of dry combustion were evaluated. From these data will be estimated the Carbon Management Index (BMI). Comparing soil-use systems for C-POX content, Bio-II presented higher results than the other systems. However, in the productive systems factor, the Bio-II obtained higher content, being statistically equal to the Adu-II and higher than the Mono-II. Comparing the management areas, the stacking was the one with the highest C-POX content, followed by the palm and carrier base. Considering the interaction between the two agroforestry systems with oil palm and the influence of the SAF zone, no significant differences were obtained, however, the C-POX content was higher in Bio-II than in Adu-II. Taking into account the management areas of the systems, the stacking had a higher result, followed by the SAF'S, palm and carrier base. Therefore, it is concluded that the oxidizable oxalizable carbon by KMnO4 is sensitive to the changes in the management of the systems, allowing to indicate that the biodiverse system presents higher quality of the soil.