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.
Plants response to the same level of salinity can be increased in hydroponic cultivation compared to under soil conditions. The study aimed at evaluating the chicory growth in DFT (Deep Flow ...Technique) hydroponic system using brackish water, comparing the results with those obtained in NFT (Nutrient Film Technique) system. The experiment was carried out in a randomized block design with eight replicates. Each plot (replicate) was represented by a hydroponic channel with 15 plants. Four treatments were used, consisting of plants grown in the DFT system submitted to three levels of electrical conductivity of nutrient solution - ECsol (2.57, 3.43 and 4.75 dS/m) and in the NFT system under ECsol of 2.57 dS/m. Plant height, number of leaves, fresh and dry matter of shoot, water consumption, water use efficiency and water content in shoot at 20 and 25 days after transplanting (DAT) were evaluated. In each harvest, a mean value was obtained per plot through of the harvest collection of five plants. At 25 DAT, the largest reductions in production and water use efficiency of chicory were observed under higher salinity (ECsol 4.75 dS/m). In the DFT system no symptoms of toxicity that could be attributed to salinity were observed.
