GROWTH RATES OF EGGPLANT UNDER DRIP AND PULSE IRRIGATION UTILISING BRACKISH WATER | TAXAS DE CRESCIMENTO DE BERINJELA IRRIGADA POR GOTEJAMENTO E PULSO UTILIZANDO NÍVEIS DE ÁGUA SALOBRA

English. Eggplant is a crop moderately sensitive to salinity and its growth and production are compromised by inadequate moisture content in the soil. In the present study, the effects of the application of brackish water via combination of drip and pulse irrigation on eggplant growth were evaluated. The experimental design used was randomized blocks, in a 4 x 4 factorial scheme, with five replications, totaling 80 plots. The treatments resulted from the combination of four forms of water application (drip and pulse throughout the crop cycle, drip in the initial phase followed by pulse in the final phase (reproductive) and pulse in initial phase followed by drip in reproductive) and four levels of electrical conductivity of irrigation water - ECw (0.3, 1.5, 3.0, and 4.5 dS m-1). The increase in the ECw reduced growth of eggplant, application of water in sequence drip/pulse irrigation promoted a greater leaf area under low salinity water and a greater dry mass of the aerial part even with the increase in water salinity. Although pulse irrigation using ECw of up to 1.5 dS m-1 favored absolute and relative growth rates in height, leaf area but reduced the stem diameter in comparison to other combinations of irrigation.

Portuguese. 1 RESUMO   A berinjela é uma cultura moderadamente sensível à salinidade e seu crescimento e produção são comprometidos pelo teor inadequado de umidade no solo. Objetivou-se avaliar os efeitos da aplicação de água salobra via combinação de gotejamento e por pulsos no crescimento da berinjela. O delineamento experimental foi blocos casualizados, em esquema fatorial 4 × 4, com cinco repetições. Os tratamentos resultaram da combinação entre quatro formas de aplicação de água: gotejamento durante todo o ciclo, pulso durante todo o ciclo, gotejamento na fase inicial seguido por pulsos na fase final (reprodutiva) e pulso na fase inicial seguido por gotejamento na reprodutiva; e quatro níveis de condutividade elétrica de água de irrigação – CEa (0,3; 1,5; 3,0; 4,5 dS m-1). O aumento da CEa reduziu o crescimento da berinjela, a aplicação de água por sequência gotejamento/pulsos proporcionou maior área foliar com água de baixa salinidade, além de maior massa seca da parte aérea com o aumento da salinidade. A irrigação exclusivamente por pulso utilizando CEa de até 1,5 dS m-1 proporcionou as maiores taxas de crescimento absoluto e relativo da altura e área foliar e reduziu o diâmetro do caule, em comparação às outras combinações de irrigação.                                                                                    Palavras-chave: Solanum melongena L., salinidade, fases fenológicas.     DAMASCENO, L. F.; COVA, A. M. W.; SILVA, R. M. S.; ALMEIDA, W. F de.; DIAS, J. A. A. L.; GHEYI, H. R. GROWTH RATES OF IRRIGATED EGGPLANT UNDER DRIP AND PULSE UTILISING BRACKISH WATER LEVELS         2 ABSTRACT   The eggplant is a moderately salt-sensitive crop and its growth and production are compromised by inadequate moisture content in the soil. In the present study, the effects of the application of brackish water via a combination of drip and pulse irrigation on eggplant growth were evaluated. The experimental design was randomized blocks, in a 4 x 4 factorial scheme, with five replications. The treatments resulted from the combination of four forms of water application (drip throughout the crop cycle, pulse throughout the crop cycle, drip in the initial phase followed by the pulse in the final phase (reproductive), and pulse in the initial phase followed by drip in the reproductive phase: and four levels of electrical conductivity of irrigation water - ECw (0.3, 1.5, 3.0, and 4.5 dS m-1). The increase in the ECw reduced the growth of eggplant, and the application of water in the drip/pulse sequence promoted a greater leaf area with low salinity water, besides a greater shoot dry mass with increasing water salinity. Pulse irrigation using ECw of up to 1.5 dS m-1 promoted the highest absolute and relative growth rates in height and leaf area and, reduced the stem diameter compared with other combinations of irrigation.   Keywords: Solanum melongena L., salinity, phenological phases.