Produtividade e qualidade de frutos cítricos em função da aplicação foliar de nitrogênio e cálcio

Abstract

The objective of this work was to study the effect of foliar fertilization with nitrogen and calcium on yield and fruit quality. The nutrients source used were the commercial fertilizer Nitroplus 9 (10% of N and 9% of Ca) and the mineral fertilizer calcium nitrate (15,5% of N and 9,5% of Ca), applied on different phenological stages of the crop. The experiment were conducted on a 4 year-old commercial orchard of Pera orange, grafted on Sunki tangerine, placed at Rio Claro, SP. It was studied five different treatments: one calcium nitrate treatment, three Nitroplus 9 different dosis and control. The treatments conducted were: 1 Control (no foliar fertilization); 2 Three foliar applications of 10 Kg ha-1 with calcium nitrate; 3 - Three foliar applications of 10,0 l ha-1 with Nitroplus 9 ; 4 - Three foliar applications of 20,0 l ha-1 with Nitroplus 9 ; and, 5 - Three foliar applications of 30,0 liters ha-1 with Nitroplus 9 . The foliar fertilizations were made on the phenological stages R1/R2 (October/2012), F1 (November/2012) and in the autumn vegetation (april/2013). The experimental design was randomized complete block with six replicates. Treatments 3, 4 and 5 lead to a significant increase on quality parameters, in other words, on total soluble solids, on ratio and on industrial yield.