Avaliação do crescimento e desenvolvimento de mudas de abacaxizeiro (Ananas comosus L.) CV, smooth Cayanne, em diferentes salinidades da água irrigada.

Abstract

With the objective to identify the effects of different leveis of salinity of the irrigation water on growth of pineapple cv. Smooth Cayenne during initial stages (up to 140 days), an experiment was carried out in greenhouse located at UFPB- Campina Grande- PB, during the period of June to October 1996. The soil utilized in the study was of the region of Salgadinho of Campina Grande, classified as regossol. A randomized block design, with 4 replications was adopted, with 8 different leveis of water salinity (electrical conductivity of 0, 1, 2, 3, 4, 5, 6 and 7 dS/m at 25°C) of the irrigation water, prepared by adding adequate volumes of NaCl and CaCl2 solutions, maintaining 7:3 proportion between Na and Ca, respectively. The pineapple suckers were planted in plastic recipients, containing 10 kg of soil and were irrigated weekly according to evapotranspiration. At monthly intervals, the volumes of water were adjusted in such a way to permit leaching equivalent to 15 % of water used during the period. Mineral fertilizers and organic manures were add following recommendations for crop. The results obtained show that, high leveis of salinity in the irrigation water, provoked signifícant reductions for ali variables (establishment index, emission of leaf, leaf area, dry weights of different parts of plant and variation in green weights), although drastic effects were verifíed in treatments with salinity leveis of irrigation water from 4 dS/m. Among the variables studied, dry weight of root was found to be most affected showing reductions of 56,7; 55,1; 52,4; 86,1; 93,2; 82,9 and 92,7% for salinity leveis in the irrigation water of 1, 2, 3, 4, 5, 6 and 7 dS/m of 25°C respectively, in relation to control. Also the leaf emission of was affected significantly by salinity leveis of irrigation water, showing reduction of 38,1% in treatment of 1 dS/m electrical conductivity. At the end of experiment, soil analysis revealed high leveis of electrical conductivity in saturation extract of soil, including control, which indicates that part of salinity to which the plant was exposed was provoked by fertilizers used.