Irrigação com água salina na cultura do abacaxizeiro no semiárido baiano

Abstract

The pineapple, with physiology characterized by the photosynthetic process Crassulaceous Acid Metabolism (MAC) presents potential for cultivation in the semi-arid region, however, there is still a lack of information related to the physiological and phytotechnical characteristics of the crop under field conditions with irrigation with saline water from tubular wells. The objective of this study was to evaluate the use of different irrigation depths with saline water in the productive, physiological, growth and quality characteristics of the "Perola" pineapple fruit in the Bahian semi-arid region, as well as to evaluate the performance of the irrigation system and impacts of salinity on soil. The study was conducted in an experimental area in the Agriculture sector of the Federal Institute of Education, Science and Technology of Bahia, Guanambi Campus. The experiment was conducted in randomized blocks with five treatments represented by irrigation blades: 100% ETc with water electrical conductivity (ECw) of 0.75 dS m-1 and C2S1 classification, 50% ETc, 75% ETc, 100% of ETc and 125% of ETc with application of water from tubular wells with ECw of 3.6 dS m-1 with classification C4S1. During the conduction of the experiment, the irrigation system was evaluated through uniformity tests, water content and soil chemical characteristics. In relation to the plant, the following physiological characteristics were measured: chlorophyll fluorescence, leaf area index, chlorophyll index, water potential and water content in the pineapple leaves. In addition, plant height, plant diameter, number of leaves, length and width of leaf "D" and leaf area were determined. Finally, the productivity and water use efficiency were estimated in addition to the quality characteristics of the fruit. In the physiographic conditions of Guanambi-BA, pineapple presents limitations of the physiological characteristics of chlorophyll fluorescence, and chlorophyll index, both under irrigation with saline water and with water of better quality. The irrigation depth of 100% ETc with CEa water of 0.75 and 3.6 dS m-1 gives the best yields. The application of saline water influences the salinization of soils. The chemical quality characteristics of the 'Pérola' pineapple fruit are within the marketing standards, except for the application of a blade referring to 125% of the ETc with CEa water of 3.6 dS m-1. The use of self-compensating drippers is limited to use with saline water, as deterioration occurs over time and, consequently, reduction of water application efficiency.