Produtividade e acúmulo de nitrato nos frutos de abobrinha em fun？？o da aduba？？o nitrogenada

despite zucchini nutritional and commercial importance, few studies have been carried out with the nitrogen fertilization of the culture. the objective of this research was to evaluate the zucchini yield (cv. caserta) and nitrate accumulation in the fruits as a function of the nitrogen fertilization. the experiment was set in a randomized block design with five rates of mineral n (0; 50; 100; 200 and 400 kg ha-1), with four replications. the number of fruits per plant, average fruit mass, fruit yield and nitrate accumulation in the fruits were significantly affected (p<0.01) by n rates. the maximum number of fruits per plant (7.7 units), mean fruit weight (240 g fruit-1) and fruit yield (29.88 t ha-1) were obtained with 323, 265 and 331 kg ha-1 of n, respectively. the maximum economical efficiency rate of n for the culture of the zucchini was 322 kg ha-1, resulting in a fruit yield of 29.86 t ha-1. the nitrate content in the zucchini fruits presented linear increment as a function of n rates. at the highest n rate, the nitrate content in the fruit fresh matter was 162 mg kg-1. this nitrate contents value does not represent risk for human health.