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UNIVERSIDADE FEDERAL DO CEARÁ (2016)

Irrigation strategies with waters of different salinity levels aimed at the sustainability of the cowpea cultivars in semi-arid production system

JOÃO VALDENOR PEREIRA FILHO

Titre : Irrigation strategies with waters of different salinity levels aimed at the sustainability of the cowpea cultivars in semi-arid production system

ESTRATÉGIAS DE IRRIGAÇÃO COM ÁGUAS DE DIFERENTES NÍVEIS DE SALINIDADE VISANDO À SUSTENTABILIDADE DO SISTEMA DE PRODUÇÃO DE CULTIVARES DE FEIJÃO-CAUPI NO SEMIÁRIDO

Auteur : JOÃO VALDENOR PEREIRA FILHO

Université de soutenance : UNIVERSIDADE FEDERAL DO CEARÁ

Grade : Doutor em Engenharia Agrícola 2016

Résumé
Salinity has constituted today one of the main problems facing irrigated agriculture. Failure to proper management of the practice of irrigation by farmers, associated the prevailing climatic conditions in arid and semi-arid regions has contributed to the accelerated process of salinization, thus leaving several inactive irrigated areas for agriculture. In this context, the work herein developed was to examine the propensity of different strategies for handling irrigation through the use of lower quality water in salinization and sodification soil, besides evaluating the morphological, physiological, biochemical and productive responses, cultivars cowpea beans, to obtain information about the better understanding of the processes involved in the responses of salt tolerance, and enable the election cultivars adapted irrigation with saline water conditions. The experiment was conducted in pots in the open, in the experimental area of the weather station of the Federal University of Ceará, Fortaleza, Ceará, under an experimental design of randomized blocks in split plots. The two water regimes (plots) were based on the potential crop evapotranspiration (100 and 50% of ETpc). Already irrigation water salinity levels (0.95 ; 2.45 ; 3.95 ; 5.45 and 6.95 dS m-1) were distributed in the subplots, while the cultivars (Epace 10 and BRS Itaim) in subsubplots. The increased concentration of salts in irrigation water reduced the plant height, number of leaves, dry weight of shoot and the pH of the soil solution, except for the electrical conductivity of the soil that kept adding to the imposition of different salt concentrations. Due to the absence of leaching, the treatments irrigated with a blade 50% of ETpc maintained higher values of soil electrical conductivity and potassium levels in the soil, providing reduction in leaf area. Through the morphological variables, the cultivar Epace 10 showed better performance than BRS Itaim. The physiological responses analyzed, it was found that the levels of chlorophyll pigments a, b, and total carotenoid contents of the well are reduced by increasing the salt concentration in the irrigation water. Under conditions of lower water availability (50% of ETpc), to cultivate Epace 10 was higher for the content of photosynthetic pigments. There was no significant change in parameters associated with the emission of fluorescence due to salt and water stress. In general, we observed reductions in the behavior of gas exchange under the rise in salinity levels, thereby enhancing the interdependence between the variables analyzed. On the productive potential and biochemical responses analyzed it was found that the concentration of salts in irrigation water provided greater accumulation of Naminossolúveis content, proline and Cl- in the bean cowpea leaves. Under a water system 50% of ETpc, the N-aminossolúveis content and K+ are higher than the system 100% of ETpc. The cultivar Epace 10 has higher accumulations N-aminossolúveis and Cl-, besides presenting more free proline accumulation, under a water system 50% of ETpc. The total yield potential of the cowpea is reduced by the addition of salts in the irrigation water. The cultivar Epace 10 showed greater tolerance imposed management conditions, making it more suitable growing conditions in regions subject to water stress and / or saline.

Mots clés : Vigna unguiculata L. Irrigation management. Salinity. Deficit water.

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Page publiée le 3 août 2017