Establishment of Young "Dwarf Green" coconut plants in soil affected by salts and under water deficit/estabelecimento de plantas jovens de coqueiro-"Anao-Verde" em solos afetados por sais e sob deficiencia hidrica

The aim was to analyze the establishment of young "Green Dwarf' coconut plants in soils affected by salts and under water stress, by evaluating leaf area, biomass production and allocation. In the experiment, conducted in protected environment in Fortaleza, CE, in statistical design of randomized blocks in a split plot arrangement, the effects of different water deficit levels (plots) were evaluated, by imposing different percentages of replacement of water losses by potential crop evapotranspiration-ETpc (20, 40, 60, 80 and 100%), associated with subplots consisting of increasing soil salinity levels (1.72, 6.25, 25.80 and 40.70 dS [m.sup.-1]) provided by soil collected at different parts of the Morada Nova Irrigated Perimeter-PIMN. Leaf area and biomass production were sharply reduced by the conditions of water stress and high soil salinity, apparently being more critical to the crop under water restriction condition. The degree of water stress can increase the susceptibility to salinity and plants can be considered, in general terms, as moderately tolerant to the effects of salinity, when combined with water deficiency. Coconut seedlings show full capacity of establishment in PIMN saline soils, corresponding to the level of electrical conductivity of 6.50 dS [m.sup.-1], but only when the water supply remains adequate. For higher salinity levels, plants survive, but their size is reduced by around 50%, even when fully irrigated. Index terms: Cocos nucifera L., initial growth, multiple stresses, salinity, drought. Objetivou-se analisar a capacidade de estabelecimento de plantas jovens de coqueiro, cultivar "Anao-Verde", em solos afetados por sais e sob deficiencia hidrica, mediante a avaliacao da area foliar, da producao e da alocacao de biomassa. No experimento, conduzido em ambiente protegido, em Fortaleza-CE, avaliaram-se, sob delineamento estatistico de blocos casualizados, no arranjo de parcelas subdivididas, os efeitos de diferentes niveis de deficiencia hidrica (parcelas), mediante a imposicao de distintos percentuais de reposicoes das perdas de agua por evapotranspiracao potencial da cultura-ETpc (20; 40; 60; 80 e 100%), associados as subparcelas, constituidas pelos crescentes niveis de salinidade do solo (1,72; 6,25; 25,80 e 40,70 dS [m.sup.-1]), proporcionados pelos solos coletados nos diferentes pontos do Perimetro Irrigado Morada Nova--PIMN. A area foliar e a producao de biomassa das plantas sao acentuadamente reduzidas pelas condicoes de rest