Cultivo do Tomate Cereja sob salinidade da água de irrigação e adubação nitrogenada.

Abstract

The use of water for irrigation with high levels of salts can be an alternative in view of the scarcity of water in the northeastern semi-arid region; however, the use of these waters can negatively affect the physiological characteristics of plants, so nitrogen fertilization can be an alternative to mitigate the deleterious effects of salinity. Thus, the objective of this work was to evaluate the gas exchange, photochemical efficiency and phytomass of cherry tomatoes cultivated with irrigation with different electrical conductivities of water and nitrogen fertilization, developed under field conditions, at the Centro de Ciências e Tecnologia Agroalimentar da Federal University of Campina Grande, Campus Pombal - PB, in a randomized block design in a 5 × 5 factorial scheme, corresponding to five levels of electrical conductivity of irrigation water - CEa (0.3; 1.3; 2.3; 3, 3 and 4.3 dS m-¹) and five doses of nitrogen (50; 75; 100, 125 and 150% of the recommended dose) with three repetitions. Cherry tomato plants were sensitive to water salinity from 0.3 dS m-1, showing a reduction in gas exchange and chlorophyll a fluorescence. The increase in the internal concentration of CO2 in cherry tomato plants is indicative of the occurrence of non-stomatal effects on the CO2 assimilation rate, at 55 days after transplanting. Irrigation with water of increasing salinity associated with nitrogen fertilization intensified the deleterious effects of saline stress on water use efficiency, shoot dry biomass and total dry biomass and cherry tomato yield. Nitrogen fertilization at a dose of 50% N mitigated the effects of saline stress on the hydrogenic potential of cherry tomato fruits. The total soluble solids contents of cherry tomato fruits were not compromised by salt stress.