Adubação fosfatada como atenuante do estresse hídrico no crescimento e produção de berinjela.

Abstract

Water is one of the limiting factors for agricultural development, both for lack and for excess, affecting growth, the development and production of plants, especially those considered sensitive. Such as eggplant, and it is important to use strategies that enable their cultivation, especially in semi-arid regions, where there is potential for cultivation and limitation of water resources. The objective of this study was to study the effect of phosphorus doses as attenuating water stress caused by irrigation slides on growth and physiology. The experiment was conducted at the AgroFood Science and Technology Center of the Federal University of Campina Grande, In the period from May to September 2016, using a randomized block design, where five phosphorus doses were studied, based on the recommendation for culture (0.0%, 50%, 100%, 150% and 200% of the recommendation) and two irrigation blades (50% and 100% ETr), making a 2 x 5 factorial scheme, totaling 10 treatments, which were repeated in four blocks, with 12 plants per plot. The eggplant seedlings, to grow Embú, were transplanted at 45 days after sowing, In the field, using the spacing of 1.0 m between rows and 0.60 m between plants, with the plot covering an area of 0.60 m2, being conducted up to 130 days after sowing, when the last Fruit harvest. As a 100% blade was obtained by estimating evapotranspiration using an equation of Penman Monteith - FAO, with data obtained from the São Gonçalo - Sousa - PB agrometeorological station. For application of the water slides, a drip irrigation system was used, with emitters of 2.6 l h-1 of flow, and spacing of 30 cm between emitters, placing a drip tape per culture line. During the cultivation period, the soil moisture was monitored by tensiometers installed in each treatment at a depth of 15 cm. Growth was evaluated by plant height, stem diameter and number of leaves; Physiological variables through gaseous changes, fruit quality variables, through physical and chemical analyzes of the fruits and the production of the plants. Fertilization above the recommendation does not provide improvements in the evaluated characteristics. Fertilization close to 100% of the recommendation had the best responses for the 50% ETr slide, where lower or higher levels of P interfered negatively in most of the characteristics evaluated. No interaction was observed between the factors evaluated (slides and doses), but under conditions of water deficit, fertilization with 100% of the recommendation provided an attenuating effect of stress. In conditions of water deficit where water is a limiting factor for irrigation, it is recommended a phosphate fertilization appropriate to the crop, however the lack of water cannot be completely bypassed with phosphate fertilization.