Fertilization can be a sustainable management practice for the maintenance of the threatened species such as Araucaria angustifolia. Our objective was to evaluate the elemental composition of A. angustifolia fertilized with N, P, and K, and how the fertilization altered the soil fertility. Seven-month-old seedlings were transplanted to 16 dm3 soil pots, and three experiments were carried separately (one for each cited element) in a completely randomized design. Overall, the seedlings tended to accumulate nutrients differently among the compartments in the following order: needles > branches > stem. Application of N reduced the soil pH, boosted Mn concentration in more 10 times, decreased the P uptake, and changed the C:N and C:P ratios. Increased doses of P led to higher uptake rates but promoted a reduction in the absorption of Mg. High rates of K diminished of P, Ca, Mg, Mn, and B, confirming antagonism interaction with Ca and Mg.
