Levels of nitrogen and potassium fertilization were evaluated on leaf nutrient contents of four commercial bromeliads, to recommend a suitable fertilization formula for each kind of plant. The experiment was a factorial (4x4) with four nitrogen (N) and potassium (K) levels (0; 375; 562.6 and 750 mg L-1of N and 0; 468.8; 703.2 e 937.6 mg L-1 of K), in randomized blocks, using four replications for Aechmea blanchetiana and Neoregelia 'Sheba' and three replications for Orthophytum gurkenii and Vriesea gigantea, and two plants per plot. Aechmea blanchetiana and Neoregelia 'Sheba' plants were grown in 50% coconut fiber + 50% cattle manure, whereas Orthophytum gurkenii and Vriesea gigantea were grown in 100% coconut fiber. The N (0; 375; 562.6 and 750 mg L-1) and K levels (0; 468.8; 703.2 and 937.6 mg L-1), on the substrate, correspond, respectively, to 0; 187.5; 281.3; 375 mg/plant of N and 0; 234.4; 351.6; 468.8 mg/plant of K. The P fertilization was fixed as 50 mg L-1 of P corresponding to 25 mg/plant of P, except for Neoregelia 'Sheba' which was inoculated with 25 mL/container (0.5 L) of the mixed inoculum (Glomus geosporum, Acaulospora laevis, Acaulospora mellea) without P fertilization. The fertilization with 305.1 mg/plant of N was the most efficient for Aechmea blanchetiana increment of plant height. In Orthophytum gurkenii the fertilization with 250 mg/plant of N caused the highest leaf number and rosette diameter. The N and K fertilization was not beneficial for Vriesea gigantea plants. In Neoregelia 'Sheba' 315 mg/plant of N caused the greatest plant height and rosette diameter.
Aechmea blanchetiana; Orthophytum gurkenii; Vriesea gigantea; Neoregelia 'Sheba'; mineral nutrition; growing media
