Estratégias de manejo com águas salobras no cultivo de berinjela

Abstract

Eggplant is a vegetable rich in nutrients that has been gaining prominence in the market due to its medicinal properties, however its production is affected by the inadequate moisture content in the soil, mainly during the flowering and fruit formation phase. Another factor that also affects the production of this vegetable is the use of white water, since eggplant is considered moderately sensitive to salinity. The study aimed to evaluate the influence of drip and pulse irrigation in two periods of phenological cycle of the eggplant crop using water with different levels of salinity. The experimental design was randomized blocks, in a 4 x 4 factorial scheme, with five replications, totaling 80 plots. The treatments were composed by the combination of four forms of water application: drip and pulses throughout the cycle; drip in the initial period (up to 65 DAT) followed by pulses in the final period (65 to 100 DAT) and vice versa; and four salinity levels of irrigation water - ECw (0.3; 1.5; 3.0; 4.5 dS m-1). Growth variables (plant height, stem diameter, number of leaves, leaf area and dry mass of the aerial parts) were evaluated, in addition to absolute and relative growth rates, production components (number of fruits, length and diameter of the fruit) and total production), water consumption and water use efficiency, and pH and electrical conductivity of the soil saturation extract after harvest. For the physicochemical analysis of the fruit, total soluble solids content, pH of the fruit, total titratable acidity and the total soluble solids / total titratable acidity ratio of treatments irrigated by drip and pulses during the whole cycle under the same saline levels were evaluated. The increase in ECw above 1.5 dS m-1 reduced eggplant growth, in addition to the total production, fruit length and water use efficiency. The application of water by pulses in the reproductive phase provided a greater number of leaves and leaf area and higher rates of absolute and relative growth of height and leaf area under low salinity water and with the increase in salinity maintained greater production of dry mass of the aerial parts. Pulse irrigation provided greater water savings and also higher electrical conductivity of the soil saturation extract at a depth of 0-0.30m. The increase in water salinity increased the content of total soluble solids and total titratable acidity, but decreased the ratio of total soluble solids / total titratable acidity.