Most commercial citrus varieties are intolerant of salinity stress, but some rootstocks, such as Rangpur lime, tolerate moderately saline irrigation water. Development of salinity-tolerant citrus may ...allow for citriculture in semiarid and arid regions where salinity stress is problematic. Because salinity stress influences shoot growth in citrus, we compared the behavioral responses of Asian citrus psyllid, Diaphorina citri Kuwayama, to salinity-stressed versus nonstressed Rangpur lime seedlings. The effects of salinity stress on key physiological processes in the seedlings were also examined. Seedlings in the control group were fertilized with a solution having a salinity of 1.7 dS m–1 while seedlings in the salinity-stressed group were fertilized with a solution having a salinity of 10 dS m–1. The seedlings were exposed to salinity stress for increasing durations (15, 20, or 60 d). Seedlings presented differential physiological responses 15 d after the imposition of salinity stress, and differences in psyllid settling rate on control versus salinity-stressed seedlings were discernable within 1 h following the imposition of salinity stress. The levels of settling, oviposition, and egg survivorship were significantly lower on salinity-stressed versus control seedlings. Olfactometer tests showed that female psyllids preferred the odor from control seedlings, suggesting that the odors of control and salinity-stressed seedlings were different. The results showed that D. citri avoids salinity-stressed seedlings; this suggests the possibility of using moderate salinity stress as a management strategy to minimize psyllid settlement and reproduction and to reduce the spread of huanglongbing, especially in citrus grown in semiarid and arid areas.
ABSTRACT The Brazilian semiarid is historically characterized by the water scarcity of good-quality. In this region there is great availability of groundwater reserves, however, these waters has high ...concentrations of dissolved salts, that makes them inappropriate to be used in the irrigation of most crops. The objective of this study was to evaluate the growth, production and salinity tolerance of three cauliflower cultivars in hydroponics NFT (Nutrient Film Technique), subjected to different electrical conductivities of the nutrient solution (ECsol) prepared with saline water. The experiment was carried out in a randomized blocks design in split-plot, with six replications. The plants were subjected to six levels of ECsol (1.94 - control, 3.24, 4.10, 5.04, 5.92 and 7.01 dS m-1) in the main plots, with three cauliflower cultivars (‘Piracicaba de Verão’, ‘Sabrina’ and ‘SF1758’) in the subplots, which were grown in the same hydroponic channel. Vegetative growth, inflorescence production and salinity tolerance of cultivars were evaluated. In general, except for the number of leaves, leaf width and fresh matters of leaves and shoot, the different ECsol levels negatively influenced the vegetative growth and inflorescences yield of cultivars cauliflower. The cultivars ‘Piracicaba de Verão’ and ‘Sabrina’ were considered moderately sensitive to salinity, while cultivar ‘SF1758’ was moderately tolerant to salinity.
RESUMO O Semiárido brasileiro é historicamente caracterizado pela escassez de recursos hídricos de boa qualidade. Nessa região há uma grande disponibilidade de água de reservas subterrâneas, no entanto, apresentam elevadas concentrações de sais, que as tornam inapropriadas para irrigação da maioria das culturas. Objetivou-se com este estudo avaliar o crescimento, a produção e a tolerância à salinidade de três cultivares de couve-flor em hidroponia NFT (Nutrient Film Technique), submetidas a diferentes condutividades elétricas da solução nutritiva (CEsol) preparadas com águas salinizadas. O experimento foi conduzido em blocos casualizados em parcelas subdivididas, com seis repetições. As plantas foram submetidas a seis níveis de CEsol (1,94 - controle; 3,24; 4,10; 5,04; 5,92 e 7,01 dS m-1) nas parcelas principais, com três cultivares de couve-flor (‘Piracicaba de Verão’, ‘Sabrina’ e ‘SF1758’) nas subparcelas, quando foram cultivadas no mesmo canal hidropônico. Avaliaram-se o crescimento vegetativo, a produção de inflorescências e a tolerância à salinidade das cultivares. De maneira geral, com exceção do número de folhas, largura foliar e as massas de matéria fresca das folhas e da parte aérea, os diferentes níveis de CEsol influenciaram negativamente o crescimento vegetativo e o rendimento das inflorescências das cultivares da couve-flor. As cultivares ‘Piracicaba de Verão’ e ‘Sabrina’ foram consideradas moderadamente sensíveis à salinidade, enquanto a cultivar ‘SF1758’ foi moderadamente tolerante à salinidade.
In order to generate information about the potential of ‘Biquinho’ pepper as an alternative crop for regions with limited supply of freshwater but with availability of brackish water, such as the ...semiarid region, a study was carried out with this crop grown in NFT (Nutrient Film Technique) hydroponic system for 120 days after transplanting (DAT). The experiment used nutrient solution prepared in water from the local municipal supply system (electrical conductivity of water –ECw = 0.34 dS m−1) and six other brackish waters prepared artificially by the addition of NaCl, with electrical conductivity of the nutrient solution -ECsol: 2.70 (control), 3.64, 4.58, 5.28, 6.09, 6.90 and 7.77 dS m−1, composing seven treatments repeated six times in randomized blocks. Fruit yield, salt tolerance and yield earliness index were evaluated. The yield of ‘Biquinho’ pepper cultivated in NFT hydroponic system, without restriction of salinity, was 2.87 kg per plant, corresponding to 46.1 Mg ha−1, considering an estimated area of 0.62 m2 per plant. A plateau followed by exponential decay model was fitted to determine the threshold salinity of ‘Biquinho’ pepper, which was 5.22 dS m−1 in the nutrient solution, corresponding to the relative potential yield. Salinity reduced the yield earliness index of ‘Biquinho’ pepper.
•Production of ‘Biquinho’ pepper is satisfactory in NFT hydroponic cultivation system.•The threshold salinity of ‘Biquinho’ pepper is 5.22 dS m−1 in the nutrient solution.•The increase in the salinity of the nutrient solution reduces the initial character of 'Biquinho' pepper production.•Nonlinear models better explained the reduction in the relative productivity of ‘Biquinho’ pepper, under NFT hydroponic cultivation.
The knowledge of water consumption and the efficiency of water use by crops is extremely important in the elaboration of agronomic and hydraulic projects of hydroponic systems. Thus, the present ...study determined the water consumption and water use efficiency of ‘Biquinho’ pepper cultivated in the hydroponic system using seven levels of electrical conductivity of the nutrient solution (ECsol) of 2.70, 3.64, 4.58, 5.28, 6.09, 6.90, and 7.77 dS m-1 and six replicates in randomized blocks. The hydroponic system used was the Nutrient Film Technique (NFT). The water consumption per plant was determined at an interval of ten days in the crop cycle (120 days after transplanting). The maximum mean daily water consumption was equal to 5.88 L plant-1 during the period 111-120 DAT, for ECsol of 4.58 dS m-1. The maximum water consumption for the crop cycle (120 DAT) was 275.66 L per plant for an estimated ECsol = 4.11 dS m-1. The highest water use efficiency (WUE), based on the total production of fruit fresh mass (ripe and unripe fruits) of ‘Biquinho’ pepper was 10.84 kg m-3 up to an estimated ECsol of 5.18 dS m-1, with an exponential reduction thereafter. The salinity of the nutrient solution, biomass production, and evapotranspiration are factors that influence the most water consumption of ‘Biquinho’ pepper.
RESUMO: O conhecimento do consumo hídrico e eficiência do uso da água pelas culturas são extremamente importantes para o dimensionamento de sistemas agronômicos e projeto hidráulico dos sistemas hidropônicos. Neste contexto, o presente estudo determinou o consumo de água e a eficiência do uso da água da pimenta ‘Biquinho’ cultivada no sistema hidropônico utilizando sete níveis de condutividade elétrica da solução nutritiva (CEsol) de 2,70, 3,64, 4,58, 5,28, 6,09, 6,90 e 7,77 dS m-1 e seis repetições em blocos casualizados. O sistema hidropônico utilizado foi a técnica do fluxo laminar de nutrientes. O consumo hídrico por planta foi determinado em um intervalo de dez dias no ciclo da cultura (120 dias após o transplantio). O consumo hídrico médio diário máximo foi igual a 5,88 L planta-1 no período de 111-120 DAT, para a CEsol de 4,58 dS m-1. O consumo máximo de água para o ciclo da cultura (120 DAT) foi de 275,66 L por planta para uma estimada CEsol = 4,11 dS m-1. A maior eficiência do uso da água (EUA) observada foi de 10,84 kg m-3 (frutos maduros e não maduros) até ao CEsol estimada de 5,18 dS m-1, com posterior redução exponencial. A salinidade da solução nutritiva, a produção de biomassa e a evapotranspiração são fatores que mais influenciam o consumo de água da pimenta ‘Biquinho’.
In the absence of matric potential, the hydroponic cultivation method of employing brackish water to prepare a nutrient solution permits satisfactory growth, even of non-leafy vegetables. The present ...study evaluated the growth variables, stem diameter, plant height, number of leaves, and the shoot dry mass in the different phenological stages of “Biquinho” pepper in response to the electrical conductivity of the nutrient solutions (ECsol), varying from 2.70 to 7.77 dS m−1 in a Nutrient Film Technique (NFT) hydroponic system. For the number of leaves, linear reductions of 3.89 and 9.29% (dS m−1)−1 were observed at 10 and 30 days after transplanting (DAT), respectively. At 60 DAT, plants began to preserve their leaves up to ECsol of 4.60 dS m−1 and presented a linear decrease of 23.32% per unit increment above the salinity threshold. At 10 DAT, the plant height and stem diameter were not affected and only at 30 DAT were there significant differences due to ECsol, with a linear reduction of 3.98 and 5.27% (dS m−1)−1, respectively. While at 60 DAT, the salinity response for these variables was represented by a plateau followed by a linear decrease, with salinity thresholds of 5.18 and 5.01 dS m−1, and thereafter a relative decrease of 9.31 and 11.9% per unit increase in ECsol above the threshold, respectively, the values up to the salinity threshold being 0.87 m and 15.77 mm, respectively. The shoot dry mass up to 60 DAT reduced linearly with an increase in ECsol, but the plants under moderate salinity after acclimatization (90 DAT) surpassed the control treatment, and maximum dry mass accumulation was observed at an ECsol of 5.14 dS m−1. The results reveal that in hydroponic cultivation of “Biquinho” pepper under salt stress, growth is attenuated in the reproductive phase.
CRESCIMENTO, PRODUÇÃO E CONSUMO HÍDRICO DO QUIABEIRO SUBMETIDO À SALINIDADE EM CONDIÇÕES HIDROPÔNICAS
FRANCISCO JOSÉ NUNES MODESTO1; MARIA ÂNGELA CRUZ MACÊDO DOS SANTOS1; TALES MILER SOARES2 E ...ELLEN PAULA MENEZES DOS SANTOS3
1 Engenheiro Agrônomo, Mestre em Engenharia Agrícola, Universidade Federal do Recôncavo da Bahia, Núcleo de Engenharia de Água e Solo, Rua Rui Barbosa, S/N, Cruz das Almas-BA, CEP 44.380-000, e-mail: fjmodesto@gmail.com; angela_macedo.08@hotmail.com
2 Engenheiro Agrônomo, Prof. Doutor, Universidade Federal do Recôncavo da Bahia, Núcleo de Engenharia de Água e Solo, Rua Rui Barbosa, S/N, Cruz das Almas-BA, CEP 44.380-000, e-mail: talesmiler@gmail.com
3 Graduanda em Engenharia Agronômica na Universidade Federal do Recôncavo da Bahia, Núcleo de Engenharia de Água e Solo, Rua Rui Barbosa, S/N, Cruz das Almas-BA, CEP 44.380-000, e-mail: ellenpaulamenezes@gmail.com
1 RESUMO
Pesquisas têm sido conduzidas com uso de águas salobras em cultivos hidropônicos e são estratégicas para o aproveitamento racional dessas águas. Nesse contexto surge o interesse em se pesquisar culturas que estão na demanda dos consumidores, como é o caso do quiabeiro. Objetivou-se com o presente trabalho analisar o consumo hídrico, o crescimento, a produção e a qualidade do quiabeiro, submetido a diferentes níveis de condutividade elétrica em sistema hidropônico. O quiabeiro foi submetido a sete níveis de condutividade elétrica da solução nutritiva (CEsol 2,08; 4,47; 7,90; 9,46; 12,84; 14,82; 18,61 dS m-1). Aos 85 dias após o transplantio foi avaliado o consumo hídrico, eficiência do uso da água (EUA), o crescimento vegetativo, a produção, a qualidade do fruto e o índice de tolerância do quiabeiro. Para a determinação da tolerância à salinidade foi utilizado, dentre outros, o modelo de platô com redução exponencial. A área foliar e o número de folhas foram as variáveis do crescimento mais afetadas com o incremento da CEsol. A EUA teve seu máximo de 7,81 Kg m-3 para a CEsol de 7,08 dS m-1. A salinidade limiar encontrada foi de 5,43 dS m-1. O aumento da CEsol até 18,61 dS m-1 não afetou a qualidade do fruto.
PALAVRAS CHAVE: Condutividade elétrica, Abelmoschus esculentus L. (Moench), qualidade da água, cultivo hidropônico.
MODESTO, F. J. N.; SANTOS, M. A. C. M. dos; SOARES, T. M.; SANTOS, E. P. M. dos
GROWTH, PRODUCTION AND WATER CONSUMPTION OF OKRA SUBJECTED TO SALINITY UNDER HYDROPONIC CONDITIONS
2 ABSTRACT
Researches have been conducted using brackish water in hydroponic crops and are strategic for the rational use of these waters. In this context the interest arises in researching cultures that are in the demand of the consumers as it is the case of the okra. The objective of this work was to analyze water consumption, growth, production and quality of okra submitted to different levels of electrical conductivity in a hydroponic system. Okra trees were submitted to seven levels of electrical conductivity of the nutrient solution (ECsol 2.08, 4.47, 7.90, 9.46, 12.84, 14.82, 18.61 dS m-1). At 85 days after transplanting, water consumption, water use efficiency (WUE), vegetative growth, yield, fruit quality and tolerance index of okra were evaluated. For determination of tolerance to salinity was used, among models, the plateau model with exponential reduction. Leaf area and number of leaves were the growth variables most affected with the increment of ECsol. WUE had its maximum of 7.81 kg m-3 for ECsol of 7.08 dS m-1. Threshold salinity found was 5.43 dS m-1. ECsol increase up to 18.61 dS m-1 did not affect fruit quality.
Keywords: Eletrical conductivity, Abelmoschus esculentus L. (Moench), water quality, soilless cultivation.
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