Comparative study on different planting systems of the Brazil nut trees established in a degraded area of the Amazon

The allocation and distribution of primary resources in planting systems can significantly influence the physiological and growth performance of Bertholletia excelsa, an Amazonian tree of significant socioeconomic and ecological importance. This study was carried out for two years to investigate the resource availability and ecophysiological responses of B. excelsa cultivated in different planting systems in 3 × 3 spacing: (1) pure plantation, (2) mixed plantation using B. excelsa and Inga edulis and (3) an agroforestry system (AFS); the AFS with intercropping of Theobroma cacao and Musa sp. between B. excelsa and I. edulis trees, respectively. Planting systems (Pure, Mixed and AFS) were evaluated based on site resource availability, growth rate, gas exchange, nutrient use efficiency, and nutritional status of B. excelsa. This study showed greater availability of light in pure plantations and a better soil quality index in the AFS. The Brazilian nut trees in the AFS showed higher values of photosynthesis (PN), stomatal conductance (gs), transpiration (E), foliar content of phosphorus, calcium, and magnesium, and greater efficiency in the use of nitrogen and potassium. Brazilian nut tree saplings showed greater investment in light capture, with greater height growth, and no difference in diameter growth rates. From the present study, it can be concluded that in the initial growth phase relating to the first installation years of field plantings, the AFS favors the ecophysiological performance and height growth of B. excelsa saplings in degraded areas of Eastern Brazilian’s Amazon.