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Oil palm is the main palm tree cultivated in the tropics, but little is understood about copper (cu) management in this crop. The objective of this study was to evaluate the nutritional status of copper in oil palms plants in the Eastern Amazon. The experiment was carried out in Tailândia, in the state of Pará (Brazil), using a completely randomized experimental design, with four replications and seven treatments (ages of oil palm plants: 2, 3, 4, 5, 6, 7, and 8 years). The concentration, accumulation, cycling, immobilization, export, and efficiency of copper use in the different organs of the plants were evaluated. The highest copper concentrations occurred in the palm heart in the second year, and copper accumulation (481 g ha−1) and export were highest in the eighth year of growth. Among the plant organs, the highest copper exports occurred in the bunches (69.38 g ha1). The highest proportion of copper was immobilized (326 g ha−1), while the lowest proportion of the nutrient accumulated in the export organs. Copper use efficiency increased with plant age, and efficiency was greater in the petiole and lower in the palm heart. The copper requirement increased with the age of oil palms grown in the Eastern Amazon. [ABSTRACT FROM AUTHOR]

Despite the importance of oil palm, there is little research related to increasing the productivity of the palm under Brazilian conditions, especially in the Amazon region. The objective of the study was to evaluate the effect of phosphorus (P), potassium (K) and magnesium (Mg) on oil palm production during the productive period in the Brazilian Eastern Amazon. The experimental area consisted of 12.64 ha with 1824 trees, spacing was in equilateral triangle (9.00 m between trees and 7.80 m between rows). The adopted design was in randomized blocks, in a factorial scheme 4 × 3 × 2, consisting of four doses of P, three doses of K and two doses of Mg. The evaluation of the experiment began at the 6th year of plant age, and the components of oil palm productivity were evaluated: numbers of fruit bunches per tree (NB), fresh fruit bunches weight per tree (BW), bunch productivity (BP) until the 12th year of plant age. Foliar analysis was performed for the nutrients N, P, K, Ca, Mg and Boron (B). The application of phosphate source promoted increases in NB, BW and BP of oil palm during all the years evaluated. Increasing the K-fertilizer dose implied increases in BW and BP in oil palm trees during all years. The application of Mg-sulfate does not promote an increase in the yield components and foliar Ca and Mg concentration of oil palm, from the 6th to the 12th year of development. [ABSTRACT FROM AUTHOR]