Abstract

Although watermelon is one of the major vegetable-fruit crop, management fertilization still lacks information for increased productivity, quality and profitability, and to lower environmental impact. An experiment was conducted in Mossoró, Brasilian city of Rio Grande do Norte, from August to October 2012, to evaluate the effects of doses of phosphorus (P) (0, 45, 90, 135, 180 and 225 kg ha^-1 P₂O₅) in productivity, quality and profitability of two cultivars of watermelon cultivation (Top Gun and Olympia), in a randomized blocks in a factorial 6 × 2, with four replications. Larger number of commercial fruits (1.70 per plant) and commercial yield (74.39 t ha^-1) were obtained with 54.8 and 49.4 kg ha^-1 P₂O₅, respectively. Attributes of quality of watermelon fruit were not influenced by P. Dose between cultivars differences were found, and 'Olympia' had higher fruit mass and skin thickness than the 'Top Gun'. However, the soluble solids content of the 'Top Gun' was 4.9% higher than the Olympia. The maximum economic return was achieved with a dose of 49.37 kg ha^-1 of P₂O₅.

Key words: Citrullus lanatus, phosphate fertilizer, production cost.