Crescimento, produtividade e composição mineral de bananeiras irrigadas com águas de salinidades diferentes.

Abstract

The understanding of the interaction between the irrigation water salinity and the growth and mineral nutrition of the crops, has fundamental importance along the cycles, in order to manage adequately the soil, water and fertilizers. The objective of this study was to evaluate the nutritional state of the banana crop, relating it with the growth and development rates in function of irrigation water salinity during the second cycle. The experiment was conducted in the Chapada do Apodi, in the municipalities of Limoeiro do Norte and Quixeré, CE, using the cultivars Prata Anã and Grand Naine, irrigated with waters of electrical conductivity of 0.31 and 1.66 dS m" . Four sampling blocks composed of six rows were used each with 32 plants totaling 192 plants in each block. Starting from 165 days after the planting (DAP) at intervals of 45 days up to the end of the cycle, four plants were collected in ítií 1 competition, separating them in rhizome, pseudostem, leaves, petiole, stem and fruits; and in each one of these parts the content of nutrients (N, P, K, Ca, Mg, Cl and Na) were determined. The growth and development evaluations (plant height, diameter of the pseudostem and leaf area) were accomplished in four plants chosen previously, in the First cycle. with the results, the growth and nutrient absorption curves were obtained for each cultivar, under two irrigation water salinity conditions. The plant growth and the development of cultivar Prata Anã irrigated with water of electrical conductivity EC of 0.31 dS m"1 was superior in comparison to the plants irrigated with water of EC of 1.66 dS m starting from 300 DAP and in cultivar Grand Naine during 345 and 435 DAP. The production of the two cultivais was not affected by the salinity of irrigation water, but between cultivars was verified in the Prata Anã plants irrigated with water of EC of 0.31 dS m" produced 21,789 kg ha"1, while irrigated with water of EC of 1,66 dS m the production was 23,440 kg ha" and in cultivar Grand Naine under the same conditions, the average production was 32,652 and 33,480 kg ha"1, respectively. In the crop the dry matter accumulation of cultivar Prata Anã irrigated with water of EC of 0.3 ldS m" was superior to the accumulation when irrigated with water of EC of 1.66 dS m , in cultivar Grand Naine the plants of high salinity accumulated more dry matter compared to less saline water. The maximum concentrations of N, P, K in the two cultivars irrigated with water of EC of 1.66 dS m"1 was in the stem, as well as the concentrations of chlorine and sodium were high in ali plant organs for the two cultivars irrigated with water of EC of 1.66 dS m" .