Abstract

The sunflower (Helianthus annus L.) crop has been gaining prominence in wastewater research due to its relevance to the production of edible oil, biodiesel and ornamental and decorative material. In the field of floriculture, the crop has been emerging as an alternative offer of a short-cycle product, with contrasting colors and easy identification by the consumer. The objective of this work was to evaluate the different electrical conductivities of water associated with nitrogen fertigation rates on the vegetative, physiological and productive behavior of ornamental sunflower. The experimental design was completely randomized, in a factorial scheme 6x4, referring to six levels of electrical conductivity of water (ECa of 0.5, 1.5, 2.5, 3.5, 4.5 and 5.5 dS m^-1) and four nitrogen fertigation rates, with one control and the other three applications performed every 10, 20 and 30 days after emergence (DAE), with five replications, totaling 120 experimental units. The variables analyzed were: stem diameter, root length, chlorophyll a, b and total chlorophyll content, fresh and dry phytomass of shoots, roots and total phytomass, seed mass and capitulum mass. The salinity negatively affected the physiological variables, growth and productivity evaluated, decreasing with increasing electrical conductivity of irrigation water (dS m^-1). Nitrogen fertigation at 10 days after emergence resulted in an increase in the stem diameter of sunflower plants.

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