Efeitos de diferentes níveis de salinidade de solo na composição química da folha e crescimento de cultivares de bananeira (Musa sp.).

Abstract

In order to identify salinity tolerant banana cultivars, an experiment was conducted; in a greenhouse located at the Campina Grande - PB UFPB, from January to June 1989. The soil used in the study came from the Irrigated Perimeter of Sumé - PB, classified as Alluvial Eutrophic, which was adjusted to the different levels of adding adequate volumes of NaCl - 2N solution, calculated from the soil salinization curve. The effect of four salinity levels on the saturation extract EC (N1 = 0.90, N2 = 3.72, N3 = 6.60, N4 = 10.75 dS / m) on the growth of four banana cultivars (C1 = Nanica, C2 = Nanicão, C3 = Pavocan and C4 = Mysore) were studied for 153 days after planting. The culture was developed in plastic containers containing 18.0 kg of soil, and the irrigations were done on alternate days, the soil being maintained around the field capacity by adding distilled or low salinity (rainwater). The percentage of germination, height, pseudocaule diameter, leaf area and dry matter weight of the plant and root, in addition to N, P, K, Ca, Mg, S, Cu, Mn , Fe, Zn, Cl and Na, in the dry matter of the middle part of the last fully open leaf, without the central rib, these results being compared to those of the International Reference Sample (AIR) observed by MOREIRA et alii (1987). The results showed that the increase of the NaCl concentration in the substrate caused a reduction in the percentage of germination of the cultivars Pacovan and Mysore, in addition to greatly affecting the height, diameter, leaf area and dry matter, mainly in the N3 and N4 levels, for all worked cultivars, The cultivars Nanica and Nanicão, Cavendish sub - group were favored with low salt concentration (up to 3.72 dS / m) and presented higher tolerance than the cultivars of group AAB, sub - group Prata (Pacovan and Mysore). Pacovan was shown to be more sensitive than to Mysore. All nutrients analyzed, except for Ca, had average levels above normal limits and, consequently, did not affect the nutritional status of the culture, while the electrical conductivity of the extract at 25 ° C from 6.60 dS / m caused foliar chlorosis, probably due to the high absorption level of the Na and Cl elements.