The effects of N, P and K levels on yield and mineral nutrition of two cupuaçu (Theobroma grandiflorum) cultivars were studied in an experiment on a Ultissol in Central Amazonia. A randomized block design with split-plots and three replications was used. The treatments applied on the plots were: N1P1K1; N1 P1 K0; N1 P0 K1; N0 P1K1; N1 P1 K2; N1 P2 K1 e N2 P1 K1; and on the split-plots: two cupuaçu cultivars, seeded and seed-less. The 0, 1 and 2 levels of N, P and K were, respectively, 0, 60 and 120 kg ha-1 of N as urea, 0, 100 and 200 kg ha-1 of P2O5 as treble superfosfate, and 0, 80 and 160 kg ha-1 of K(2)0, as KCl. Based on this study, it was not possible to make formal recommendations for fertilization of cupuaçu, however, trends in mineral nutrient requirements for this crop were evident. Based on the 3year mean yield, nitrogen fertilizer had no effect on crop yields, neither P fertilizer at high levels. However, a positive linear yield response to K application was observed, principally for the seeded cultivar. The lowest yield occurred in the absence of P.
Theobroma grandiflorum; fertilization; mineral nutrition; available nutrients
