Interação e ponto de equilíbrio na assimilação de carbono em sistemas agroflorestais na Amazônia oriental.

Abstract

This study presents the results of the evaluation of the interaction and balance between biotic and abiotic factors combined in carbon assimilation between two types of agroforestry systems (SAF): a cultivated in Cametá-PA (SAF-CM), classified as traditional and other in Tome-Acu-PA (SAF-TA), classified as commercial. Was used in the study eight sample plots of 50 m x 50 m (0.25 ha), four in each area, divided into ten sub-plots of 10 mx 25 m, which measured the diameter at breast height (DBH) and measured the total height (H) of all individuals (ni) with DBH  5 cm. Were inventoried in the SAF-CM a total of 9,932 ni/ha, average of 2,458 ni/ha, belonging to 10 families, 13 genera and 13 species and SAF-TA a total of 4,996 ni/ha average of 1,249 ni/ha, belonging to 9 families, 13 genera and 13 species. Euterpe oleracea and Theobroma cacao, were the most important species in the two areas of this study, other species also stood out: Virola surinamensis, Hevea brasiliensis and Carapa guianensis in SAF-CM, and Spondia lutea, Bertholletia excelsa and Swietenia macrophylla in SAF-TA; with results ratified by the floristic and structural analysis. The fuel wood and coal (energy) was more frequent (73.7%) in SAF-CM, while the use in general construction (69.2%) in SAF-TA. The high percentage of species of domestic consumption (65%) in SAF-CM and commercial species (93%) in SAFTA reveal the stark contrast between the traditional SAF focused on biodiversity and commercial SAF focused on production/sale. Both SAF-CM as the SAF-TA stock of carbon (EC) contained in the dry biomass (BS) above ground level was higher in the trees than in açaí (Euterpe oleracea) and cocoa (Theobroma cacao); management adopted in SAF influence the EC contained in the BS. In this sense the SAF-CM showed greater efficiency than the SAF-TA. Mathematical modeling prey-predator populations in Carbon and plants in the study showed that SAF SAF-CM were more interactive and balanced that SAF-TA, because a higher number of events. The predator-prey model showed aptitude and efficiency in appraisal interaction and breakeven in carbon assimilation among populations Carbon (abiotic) and plants (biotic) grown in SAF, ie, it is not only commercial species, but vegetation composing the system and its internal and external interactions with the environment in their surroundings (vegetation, soil, water). Furthermore, the results presented above confirm the SAF and emerge as an alternative for sustainable production, demonstrating its ability to generate products for domestic consumption and sale, and also socio-economic and ecological suitability of these important agricultural ecosystems in the eastern Amazon, in its particularities.