Biofertilizante de manipueira como atenuante do estresse salino no cultivo irrigado do maracujazeiro amarelo

Abstract

The passion fruit tree (Passiflora edulis Sims) belongs to the Passifloraceae family, and has great socioeconomic importance in Brazil, due to its high production, consumption, employment and income generation. The use of brackish water in passion fruit cultivation in the semi-arid region of the Brazilian Northeast can be made possible through the use of biofertilizers that can attenuate the deleterious effects of saline stress. Given the above, the objective of this study was to evaluate the effect of doses of manipueira biofertilizer as a mitigating factor for saline stress on growth, production and postharvest quality of passion fruit cv. BRS Sol do Cerrado F1 irrigated with saline water. The study was controlled in a greenhouse, in a completely randomized experimental design, with three replications, in a split-plot scheme. The plots were constituted by the levels of electrical conductivity of the irrigation water - ECa (0.9; 1.8; 2.7; 3.6 and 4.5 dS m-1). The subplots consisted of four doses of potassium (25; 50; 75; 100%) depending on the concentration of the element in the manipueira biofertilizer). Irrigation with water with electrical conductivity above 0.9 dS m-1 affected the physiological indices, growth and production components of sour passion fruit. However, the use of manipueira at a dose of 75% of the potassium recommendation mitigated the deleterious effects of irrigation water salinity, with the best results obtained in plants irrigated with ECa of 0.9 and 1.8 dS m-1. The use of manipueira in doses greater than 75% of the potassium recommendation intensified the deleterious effects of irrigation water salinity on the morphophysiology and production components of the passion fruit tree. Irrigation with ECa above 3.0 dS m-1 affected the pH and included the ascorbic acid contents of the passion fruit pulp. The use of biofertilizer with a dose of 100% of the potassium recommendation is excessive for passion fruit under conditions of saline stress. However, a dose of 75% can be used to replace chemical fertilization.