Macadamia (Macadamia integrifolia) has a high nut abortion rate. Unbalanced nutrition may be one of the factors that contributes to this problem. The aim of this study was to evaluate the influence of N doses and the split application of NPK fertilizers on fruit abortion of macadamia nut. Two experiments were conducted during three growing seasons on an Oxisol, in Jaboticabal, São Paulo State, Brazil. The first experiment consisted of five N rates (0, 50, 100, 150 and 200 kg ha-1 yr-1) and four replications. The second experiment consisted of four splitting modes of NPK fertilizers (T1: October, T2: October + December, T3: October + December + February and T4: October + December + February + April) and five replications. Most fruits (77.7%) aborted earlier in their development. The N application and the split fertilization of NPK as topdress for at least twice (October and December), did not affect the number of aborted fruits per macadamia tree, but, by increasing the total number of set fruits and reducing the percentage of abortion, provided higher nut productivity.
Macadamia integrifolia; nutrition; split fertilization; abscission
