Effect of nitrogen and potassium fertigation on the quality of Italian zucchini fruit

The objective of this study was to evaluate the effect of nitrogen and potassium fertigation on the quality of ‘Novita Plus’ Italian zucchini fruit. The experiment was conducted under greenhouse conditions at the Technical Center of Irrigation, Department of Agronomy of the State University of Maringá. The drip irrigation system was used such that each plant was irrigated by a dripper operating at a nominal flow of 4 L h-1 and a service pressure of 10 m.c.a., which was controlled by means of a pressure gauge of glycerin installed in the control head of the system. A completely randomized design was used. The experiment was arranged in a factorial design (4 × 4) with three replicates. The treatments applied to the plants were in the combination of four N doses (0 kg ha-1 N, 90 kg ha-1 N, 180 kg ha-1 N, and 270 kg ha-1 N) with four doses of K (0 kg ha-1 K2O, 90 kg ha-1 K2O, 180 kg ha-1 K2O, and 270 kg ha-1 K2O). The following fruit variables were evaluated: pH, titratable acidity, fruit diameter, and fruit length. The N and K doses applied through irrigation water significantly influenced the fruit variables. However, no significant effects of N and K fertigation were found in the interaction between the N and K doses applied.