Productivity and physico chemical quality of yellow passion-fruit cultivated under different nitrogen sources through fertigation

Nitrogen is the most required and limiting nutrient in the yellow passion-fruit yield. Fertilization through irrigation water provides more rational and efficient use of fertilizers. This study aimed at assessing productive and qualitative parameters of yellow passion-fruit based on different sources and doses of nitrogen through fertigation in Vale do Gurgueia – PI. The experiment was conducted from June 2013 to August 2014 in the city of Cristino Castro – PI. The experimental design was randomized and arranged in a 2 x 5 factorial scheme, with four replicates. Treatments were consisted of combined two nitrogen sources (urea and ammonium sulfate) and five nitrogen levels (100, 200, 300, 400 and 500 kg ha-1 year-1), each plot had six plants 3.0 x 3.0 m spaced, totaling 1,111 plants ha-1. The fertigation, occurred during the crop cycle, was weekly performed. Yield was evaluated per plant, productivity and mean weight of fruit. In pulp, pH, soluble solids, titratable acidity, (SS/TA) ratio and pulp percentage were evaluated. Increased ratios of N, ammonium sulfate source, cause reduction in fruit pulp percentage of the yellow passion-fruit. Soluble solids and pH of fruit pulp have chemical quality within ranges established by normative instruction of MAPA. To urea source, it is recommended 227.87 kg ha-1of N for a productivity of 15.48 t ha-1and 309.5 kg ha-1of N, as ammonium sulfate, for a productivity of 14.92 t ha-1.