Salinity and flow rates of nutrient solution on cauliflower biometrics in NFT hydroponic system

Abstract

The use of brackish water in hydroponic crops represents an alternative for vegetable production. In this context, two experiments were conducted to evaluate the effect of using brackish water to prepare the nutrient solution and replace the evapotranspired depth, applied at different flow rates, on cauliflower biometrics in NFT (nutrient film technique) hydroponic system. In both experiments, the experimental design was completely randomized with four repetitions, in a 6 x 2 factorial scheme: six levels of water electrical conductivity (ECw) in interaction with two flow rates of nutrient solution application in the hydroponic channels (1.5 and 2.5 L min-1). In Experiment I, brackish waters with different EC (1.5, 2.5, 3.5, 4.5 and 5.5 dS m-1), obtained by the addition of NaCl in public-supply water (0.2 dS m-1), were used. In Experiment II, the chemical characteristics of brackish waters collected in the semiarid region of Pernambuco were simulated, with EC of 1.67, 3.30, 4.71, 5.88 and 13.84 dS m-1, plus the control (0.2 dS m-1). Increasing salinity reduced cauliflower growth. Flow rate of 1.5 L min-1 promoted the best results of shoot fresh and dry masses, leaf area, number of leaves, plant height and shoot diameter. The best water for cauliflower production was public-supply water and, among the well waters, the best was the calcium sulfate-rich water with EC of 1.67 dS m-1.

Effect of the Flow Rate on Plant Growth and Flow Visualization of Nutrient Solution in Hydroponics

“…Due to the greater nutrient accumulation in the shoots and use efficiency of these elements, the highest production (g/plant) of lettuce was obtained with a flow rate of 1 L/min of nutrient solution. Soares et al [11] used brackish water for hydroponic vegetable production and tested the flow rates of two nutrient solutions in the hydroponic channels. The best shoot fresh weight and dry weight, leaf area, number of leaves, plant height, and shoot diameter values were obtained at a flow rate of 1.5 L/min.…”

Water yield and consumption of cauliflower plants grown in a hydroponic system using brackish waters and different flow rates

“…The salt proportion and concentration in the waters used for the preparation of the solutions nutritious were simulated under laboratory conditions to coincide with the salt concentrations of the waters of wells in the Moxotó River basin (Soares et al, 2020), specifically in the municipality of Ibimirim, PE, Brazil, and due characterized as described in Table 1.…”

“…(3) Decreases in plant growth due to increases in salinity of the nutrient solution may be due to the osmotic effect of the higher ion concentrations in the nutrient solutions on the plants (Soares et al, 2020). The high Na + and Clconcentrations in the brackish waters (Table 1) probably caused imbalances in the plant nutrient absorption, since excess Na + and Clions in the nutrient solution can cause imbalances in the absorption of essential nutrients, such as nitrogen, calcium, and potassium (Abbasi et al, 2016).…”

“…However, despite NFT hydroponics is used for crops that are relatively tolerant to salt stress, such as cauliflower (Giuffrida et al, 2016), it presents specificities regarding the use of brackish waters that still require studies. These specificities include the frequency and flow rate of the circulation of the nutrient solution (Silva Júnior et al, 2019;Soares et al, 2020), and the chemical composition of the waters used for the crops (Martins et al, 2019).…”

Cauliflower Growth and Yield in a Hydroponic System With Brackish Water

“…Some studies have evaluated cauliflower plants grown in soil (De PASCALE;MAGGIO;BARBIERI, 2005), pots with sand (GIUFFRIDA et al, 2013;GIUFFRIDA et al, 2017;GIUFFRIDA et al, 2018), and NFT (Nutrient Film Technique) hydroponic system (CRUZ et al, 2018;SOARES et al, 2020) under salt stress conditions. De Pascale, Maggio and Barbieri (2005) determined a threshold salinity of 1.52 dS m -1 for cauliflower in soil irrigated with brackish waters.…”