RESUMO Objetivou-se determinar a eficiência fotoquímica da palma forrageira ‘Gigante’ cultivada sob diferentes espaçamentos e doses de esterco bovino na região semiárida. O experimento foi conduzido em blocos ao acaso em esquema fatorial 4 x 3 x 7, com três repetições. O primeiro fator foi constituído de quatro doses de adubação orgânica (0; 30; 60 e 90 Mg ha-1 ano-1 de esterco bovino), o segundo, por três espaçamentos (1,0 x 0,5; 2,0 x 0,25 e 3,0 x 1,0 x 0,25 m) e o terceiro por sete horários de leitura (6; 8; 10; 12; 14; 16 e 18 h). Foram realizadas leituras de fluorescência da clorofila a em cladódios de palma forrageira nas épocas seca e chuvosa com auxílio de um fluorômetro de luz modulada. Os cladódios de palma forrageira ‘Gigante’ cultivada sob diferentes espaçamentos e doses de esterco bovino sofrem alterações no fotossistema II na época seca nas condições fisiográficas do semiárido baiano. Na época de chuvas na região semiárida o rendimento fotossintético em cladódios de palma forrageira é considerado ideal.

ABSTRACT The objective of this study was to determine the photochemical efficiency of ‘Gigante’ cactus pear cultivated under different spacings and bovine manure doses in the semi-arid region. The experiment was conducted in a randomized block design in a 4 x 3 x 7 factorial scheme, with three replicates. The first factor consisted of four doses of organic fertilization (0, 30, 60 and 90 Mg ha-1 year-1 of bovine manure), the second one, of three spacings (1.0 x 0.5, 2.0 x 0.25 and 3.0 x 1.0 x 0.25 m) and the third one of seven reading times (6, 8, 10, 12, 14, 16 and 18 h). Chlorophyll a fluorescence readings were taken in cactus pear cladodes in the dry and rainy seasons using a pulse-modulated fluorometer. Cladodes of ‘Gigante’ cactus pear cultivated under different spacings and bovine manure doses undergo changes in photosystem II during the dry season under the physiographic conditions of the semi-arid region in Bahia. During the rainy season in the semi-arid region, the photosynthetic yield in cactus pear cladodes is considered ideal.

Abstract This study aimed to evaluate Pome type bananas grown under different irrigation systems. Seventy-two treatments were used in a factorial 3×2×12 scheme, where factors consisted of three irrigation systems (under-tree sprinkling, micro-sprinkling, and dripping), two cultivars (‘Prata-Anã‘ and ‘BRS Platina’), and twelve evaluation periods (months). The treatments were arranged in a completely randomized design with five repetitions. During the third production cycle, plant phytotechnical and physiological traits were evaluated in different months at five different times of the day. The results showed no significant interactions between cultivars and irrigation systems. All the assessed traits varied for each irrigation system, except for plant yield. The banana plants presented higher vigor and a larger number of hands when grown under conventional sprinkling and micro-aspersion systems, regardless of the cultivar. The cultivar ‘Prata-Anã‘ has larger leaf areas and number of hands, regardless of the irrigation system. Moreover, plants irrigated by dripping exhibited higher leaf temperatures, higher transpiration rates, and lower instant water-use efficiency. When irrigated by micro-sprinklers, the plants displayed greater water-use efficiency. As leaf temperature rose, perspiration increased linearly, while the instant water-use efficiency decreased linearly.

RESUMO Objetivou-se avaliar as características fisiológicas e a produtividade do abacaxizeiro ‘Pérola’ submetido à irrigação com água salina no semiárido baiano. O experimento foi conduzido em blocos casualizados com cinco tratamentos representados pelas lâminas de irrigação: 100% da ETc com água de condutividade elétrica (CEa) de 0,75 dS m-1 e 50, 75, 100 e 125% da ETc com aplicação de água de CEa de 3,6 dS m-1. Utilizou-se o sistema de irrigação por gotejamento, com gotejadores autocompensantes de vazão nominal de 8 L h-1. Nas condições fisiográficas de Guanambi, BA, o abacaxizeiro apresenta limitações das caraterísticas fisiológicas de fluorescência da clorofila e índice de clorofila, tanto sob irrigação com água salina, quanto com água de melhor qualidade. A lâmina de irrigação referente a 100% da ETc com água de CEa de 0,75 e 3,6 dS m-1 proporciona as melhores produtividades.

ABSTRACT The objective of this study was to evaluate the physiological characteristics and yield of ‘Pérola’ pineapple subjected to irrigation with saline water in the semi-arid region of Bahia. The experiment was conducted in randomized blocks with five treatments, represented by irrigation depths: 100% ETc, using water with electrical conductivity (ECw) of 0.75 dS m-1, and 50, 75, 100 and 125% ETc, using water with ECw of 3.6 dS m-1. The experiment used a drip irrigation system and pressure-compensating emitters with a discharge of 8 L h-1. In the physiographic conditions of Guanambi-BA, pineapple has limitations of the physiological characteristics of chlorophyll fluorescence and chlorophyll index, under irrigation with both saline water and better-quality water. The irrigation depth corresponding to 100% ETc using water with ECw levels of 0.75 and 3.6 dS m-1 led to the best yields.

RESUMO Objetivou-se, com o presente trabalho, selecionar equações de regressão com base na correlação entre o índice de clorofila e os teores foliares de nutrientes para predição em tempo real do estado nutricional de bananeiras tipo Prata. Utilizaram-se, como tratamentos, seis cultivares de bananeira tipo Prata com cinco repetições e quatro plantas úteis por parcela, dispostas em delineamento experimental inteiramente casualizado. Avaliaram-se os teores de nutrientes com base em análises laboratoriais e os índices de clorofila com um medidor portátil na terceira folha do ápice para a base. Os dados foram submetidos à análise de variância; calcularam-se as correlações entre teores foliares de nutrientes e índices de clorofila e se ajustaram equações de regressões para as associações significativas e com maior magnitude. Os modelos selecionados estimam os teores foliares de nutrientes e permitem predizer com segurança em tempo real e a baixo custo, o estado nutricional de bananeiras tipo Prata. Constitui uma técnica auxiliar que, aliada à diagnose foliar e à análise de solos, contribui para uma avaliação nutricional mais criteriosa e segura.

ABSTRACT This study aimed to select regression equations based on the correlation between chlorophyll index and leaf nutrient contents, for real-time prediction of the nutritional status of 'Prata' banana. Six cultivars of 'Prata' banana were used as treatments, with five replicates and four plants per plot, arranged in a completely randomized design. Nutrient levels were evaluated based on laboratorial analysis and chlorophyll indices using a portable chlorophyll meter, in the third leaf from the apex to the base. Data were subjected to analysis of variance, calculating the correlations between leaf nutrient contents and chlorophyll indices, and the regression equations were adjusted to the associations that were significant and with greater magnitude. The selected models estimate leaf nutrient contents and allow a real-time, low-cost reliable prediction of the nutritional status of 'Prata' banana. It is an auxiliary technique that, combined with leaf and soil analysis, contributes to a more precise and secure nutritional evaluation.