Concentration In Nutrient Solution Research Articles

Growth Dynamics and Nutrient Removal from Biogas Slurry Using Water Hyacinth

Aquatic macrophytes, notably the invasive water hyacinth, exhibit proficiency in nutrient removal from polluted water bodies, rendering them appealing for water remediation applications. This study investigates the potential of water hyacinth in phytoremediation, focusing on the effect of using nutrient-rich biogas slurry mixed with water in varying concentrations, i.e., 16.6, 33, 66.6, 100, and 133 mg/L for the investigation. The physiochemical properties of the liquid biogas slurry were evaluated before and after treatment with water hyacinth over eight weeks, with continuous monitoring of nutrient reduction rates. Results showcased substantial average reductions of nitrogen, phosphorus, and potassium, with a relative growth rate of 5.55%. The treatment also decreased pH, total dissolved solids, hardness, and chemical oxygen demand. The theoretical BMP of water hyacinth was determined using Buswell’s equation. Water hyacinth grown in the concentration of the biogas slurry exhibited the highest methane yield at 199 mL CH4/gm VS, along with the highest relative growth rate. This study used experimental data to create a mathematical model that describes how the relative growth of water hyacinth depends on the number of days and biogas slurry concentration (C). The model’s quality and effectiveness were evaluated using the goodness of fit (R2) and observable approaches. The polynomial model, referred to as Poly model 1, 2, is the best fit for describing the relationship between the growth percentage of water hyacinth, days, and nutrient solution concentration. In this model, C has a polynomial degree of one (normalized mean of 69.84 ± 43.54), while D has a degree of two (normalized mean of 30 ± 21.65).

The responses of pepper plants to nitrogen form and dissolved oxygen concentration of nutrient solution in hydroponics

BackgroundThe presence of oxygen in the growth medium is absolutely essential for root development and the overall metabolic processes of plants. When plants do not have an adequate oxygen supply for respiration, they can experience a condition known as hypoxia. In order to investigate the impact of different nitrogen forms and varying oxygen levels in nutrient solutions on the growth, photosynthesis, and chlorophyll fluorescence parameters of bell pepper plants, a comprehensive study was conducted. The experiment was designed as a factorial experiment, considering two main factors: nitrogen forms (calcium nitrate and ammonium sulfate) with a fixed nitrogen concentration of 5 mM, and the oxygen levels of the nutrient solutions (ranging from 1.8 ± 0.2 to 5.3 ± 0.2 mg. L-1).ResultsThe study examined the effects of nitrogen (NH4+ and NO3−) application on various parameters of vegetative growth. The results demonstrated that the use of ammonium (NH4+) led to a reduction in the most measured parameters, including the fresh and dry mass of both the root and shoot, at low O2 concentrations of 1.8 ± 0.2; 2.6 ± 0.2 and 3.8 ± 0.2 mg. L-1. However, an interesting observation was made regarding the impact of oxygen levels on root growth in plants grown with nitrate (NO3−). Specifically, the highest levels of oxygen significantly increased root growth in NO3−-fed plants. Additionally, the application of NH4+ resulted in an increase in chlorophyll concentration in the leaves, particularly when combined with high oxygen levels in the nutrient solution. On the other hand, leaves of plants fed with NO3− exhibited higher photosynthetic rate (A), intrinsic water use efficiency (iWUE), and instantaneous carboxylation efficiency (A/Ci) compared to those fed with NH4+. Furthermore, it was found that NO3−-fed plants displayed the highest instantaneous carboxylation efficiency at oxygen levels of 3.8 and 5.3 mg. L-1, while the lowest efficiency was observed at oxygen levels of 1.8 and 2.6 mg. L-1. In contrast, NH4+-grown plants exhibited a higher maximal quantum yield of PSII photochemistry (Fv/Fm), as well as increased variable fluorescence (Fv) and maximum fluorescence (Fm), compared to NO3−-grown plants. Interestingly, the NO3−-fed plants showed an increase in Fv/Fm, Fv, and Fm with the elevation of oxygen concentration in the nutrient solution up to 5.3 mg. L-1.ConclusionThis study showed that, the growth and photosynthesis parameters in bell pepper plants are sensitive to oxygen stress in floating hydroponic culture. Therefore, the oxygen level in the nutrient solution must not be lower than 3.8 and 5.3 mg. L-1 in NH4+ and NO3− –supplied culture media or nutrient solutions, respectively.

Optimizing nutrient solution for vegetative growth of Dendrobium Tubtim Siam and Phalaenopsis Taisuco Swan through plant tissue nutrient balance estimation

BackgroundOrchids are grown without soil in many regions of the world, but there is a lack of studies to define the balanced and adequate nutrient solution for their cultivation, mainly in the vegetative growth phase. Therefore, this paper aims to evaluate the optimal concentration of the nutrient solution based on the proposal by Hoagland and Arnon (1950) in the vegetative growth phase capable of increasing the nutrient contents, growth, and dry matter production of Dendrobium Tubtim Siam and Phalaenopsis Taisuco Swan. In addition, this paper aims to estimate a new nutrient solution from the optimal nutrient contents in the dry matter of these orchid species to be used in the vegetative growth phase.ResultsNutrient contents, growth, and dry matter production increased as the nutrient solution concentration increased up to an average concentration of 62 and 77% for D. Tubtim Siam and P. Taisuco Swan, respectively. We found that the Hoagland and Arnon solution presented a group of nutrients with concentrations above the requirement for P. Taisuco Swan (nitrogen, phosphor, calcium, and sulfur) and D. Tubtim Siam (phosphor, calcium, magnesium, and sulfur), while other nutrients in the solution did not meet the nutritional demand of these orchid species, inducing nutritional imbalance in the vegetative growth phase.ConclusionWe conclude that using a balanced nutrient solution created specifically for each orchid species in vegetative growth might favor their sustainable cultivation by optimizing the use of nutrients in the growing medium.

Growth, phytochemical concentration, nutrient uptake, and water consumption of butterhead lettuce in response to hydroponic system design and growing season

Two hydroponic system designs (nutrient film technique: NFT, and deep water culture: DWC) were set up in a climate-controlled greenhouse to compare growth, nutrients and water uptake patterns, yield and quality of lettuce (Lactuca sativa cv. Butterhead) during fall (October through November) and summer (July-August) growing conditions. The research was conducted with four system replicates for each hydroponic design and each system contained nine lettuce plants. Plant photosynthetic properties, growth parameters, and irrigation solution nutrient concentrations were measured weekly. At the end of the production cycle, plants were harvested for leaf area, fresh and dry yield of shoots and roots, nutritional and phytochemical concentrations. In the study, DWC system had better water quality properties than NFT including less seasonal water temperature fluctuation, which supported lettuce with better photosynthetic rates, growth rate and fresh yield in fall. Tipburn symptoms were only observed in summer, and NFT grown lettuce had significantly lower shoot calcium and magnesium concentrations than DWC in both fall and summer seasons, which led to more severe tip burn symptom in summer. In addition, better water quality in DWC also benefited lettuce with higher antioxidant concentrations than NFT, which included 9.4 % higher vitamin C in fall, 34.6 % higher total carotenoids in fall, 40.6 % higher non-acidified phenols in fall, as well as 12.9 % higher total chlorophyll in summer. Although there were marginal differences in fresh yield, most types of mineral nutrients and antioxidants between DWC and NFT, DWC performed better than NFT with less tipburn in summer as well as increased yield, total carotenoids, vitamin C and non-acidified phenols in fall.

Microclimate Control in Strawberry Production with Hydroponic System in Indoor Vertical Farming

The purpose of this paper is to analyze Microclimate Control in strawberry production using hydroponic system in Indoor Vertical Farming. This research will discuss the Microclimate parameters that affect strawberry growth to be controlled in maintaining strawberry productivity. The parameters controlled include temperature, humidity, CO2 levels, light and EC/pH of nutrients. The data collection technique of this research is taken using Priva Climate Computer technology whose settings are adjusted to the target parameters set and analyzed using the Priva Cloud Office Direct Client application which is part of the Priva Climate Computer technology. The results of the Microclimate control carried out, obtained temperature 17,8-20,9ºC, humidity 67,4-91,3%, Carbon Dioxide (CO2) levels 597-600 ppm, light with light intensity PPFD 29,9 μmol m-2s-1 and nutrient solution concentration with Electrical Conductivity (EC) 0,9-1,18 mS/cm and pH 5,8-6,1 in Indoor Vertical Farming. After going through a series of studies, the results of measuring environmental parameters are in accordance with the targets that have been set. It can be concluded that the results of the study are in accordance with the recommendations for environmental parameters for the growth of large and uniform strawberries. The results of this study can be used as a reference for readers to increase knowledge, practice commercial directly and become a reference for further research. 
 

Influence of Nutrient Solutions in an NGS® Soilless System on the Yield, Quality and Shelf Life of Fresh-Cut Commercial Mint at Different Harvest Times

The optimal fertilizer concentration for Mentha plants is contingent on the growing systems and harvest time, serving as operational solutions to control and enhance quality and yield. This study aimed to determine the effects of three macronutrients concentration in hydroponic nutrient solution (HNS) during three harvest times on the growth, quality, yield, and shelf life of three mint species (M. spicata L. var. viridis (MV); M. piperita L. (MP); M. spicata L. var. rubra (MR)) grown in a New Growing System (NGS®). Total dry matter (DM), nitrate (NO3−), phosphate (PO43−), and calcium carbonate (CaCO3) concentrations were increased with the addition of higher levels of nutrient fertilization in three species. When the ion concentration of the HNS was increased, total fresh yield decreased. The highest total bacterial count (TBC) was obtained in MR species in the three harvests in all the levels of HNS. The lowest browning potential (BP) and soluble o-quinone (So-Q) levels were observed at second harvest in the MR species with the application of one of the two HNS high in nitrogen (N). In conclusion, the combination of optimal HNS ion concentration and appropriate species is considered essential to obtain suitable yield, quality, and ensure shelf life of mint.

BIOSTIMULATION OF CUCUMBER CROP PRODUCED IN SHELTERED CONDITIONS

Objective: To evaluate the physiological and productive response of cucumber crop to the induction of three commercial phytohormones (Cito Xplosión, Súper Hormonal, Vitaminum Forte) grown under protected conditions. Design/methodology/approach: The experiment consisted of three treatments, T1 (Cito Xplosión), T2 (Súper Hormonal), and T3 (Vitaminum Forte). The evaluated variables were plant height, number of leaves, fresh biomass, fruit diameter and length, number and weight, total soluble solids, pH, and electrical conductivity. Results: In the physiological variables, values of plant heights were 225, 228, 220, and 238 cm for T1, T2, T3, and the control. 33 leaves for all treatments and 31 for the control, T1 and T2 produced higher fresh biomass in leaves, stems, roots, and flowers, while T3 produced higher biomass in fruits. For the fruit length, the values were 16.9, 17.6, 17.6, and 18.4 cm, and diameters of 5.2, 5.2, 5.1, and 5.1 cm for T1, T2, T3, and the control. The weight of fruits was 293.2, 297.3, 283.9, and 281.7 g with yields of 10.1, 10.9, 10.0, and 9.6 kg m-2 for T1, T2, T3, and the control. Limitations on study/implications: More varieties should be evaluated using different nutrient solution concentrations and management practices as a function of the number of stems to assess whether phytohormones influence physiological or productive variables. Findings/conclusions: From an economic point of view, T2 was the best treatment, achieving a higher yield and fruit quality.

Effect of Nutrient Solution Concentration on Growth, Yield, and Fruit Quality of Tomato Grown Hydroponically in Single-Truss Production System

Abstract The single-truss production system for tomatoes (Solanum lycopersicum L.) is a relatively new developed cultivation technology that guarantees high yields and high-quality fruit throughout the annual cycle. In this study, we examined the impact of electrical conductivity (EC) of nutrient solutions on the growth, yield, and fruit quality of tomatoes grown in a single-truss system in a hydroponic culture. Plants were supplied with nutrient solution at the following EC values: 0.8, 1.0, 1.2, and 1.4 mS·cm−1 in the spring and summer cycles, and at 1.0, 1.2, 1.4, and 1.6 mS·cm−1 in the winter cycle. In the spring cycle, the EC of the nutrient solution increased in all treatments, particularly after pinching the main stem. Increased EC values of nutrient solutions were also recorded at the 1.2 and 1.4 EC in the summer cycle and the 1.4 and 1.6 EC in the winter cycle. The leaf number per plant did not differ between treatments in all production cycles. The largest leaf area was found at the 1.2 and 1.4 EC in the spring cycle and the 1.0 and 1.2 EC during the summer. During the winter cycle, no differences in leaf area between treatments were observed. In spring, plants at the 1.2 and 1.4 EC had the highest yields and largest fruits, while during the summer, plants at the 1.0 and 1.2 EC produced the most fruit. In winter, the highest yield was found at the 1.4 EC. The soluble solids concentration (SSC) of fruit was increased at the 1.4 EC both in the spring and summer cycles, while in the winter cycle, there was no difference between the treatments. Only fruit at the 1.4 EC in the summer cycle had an increased acidity. The findings indicate that under greenhouse conditions, tomato cultivation in a single-truss system can be successful if the plants are supplied with a nutrient solution at an EC value of 1.2–1.4 mS·cm−1.

Effect of nutrient solution concentrations and irrigation levels combined with humic acid on physiological and quality characteristics of rocket crop (Eruca sativa (mill.) thell.)

Water resources pose a considerable limitation in arid and semi-arid regions like Iran, primarily due to the scarcity of rainfall and heightened evaporation rates. Within open hydroponic systems, a significant concern arises from the depletion of nutrient solutions utilized for crop fertigation. This predicament subsequently gives rise to environmental issues of note and a discernible surge in production expenses. Application of humic acid (HA), as a plant biostimulant, enhances plant tolerance to reduced water supply and counterbalances the effects of diluted nutrient solutions. A greenhouse experiment was conducted to investigate the impact of applying HA (600 ppm) in conjunction with three nutrient solution concentrations (complete nutrient solution (NSc), 75% NSc (NS1), and 50% NSc (NS2)), as well as two irrigation levels (100 and 50% of plant water requirement, IL100 and IL50, respectively). The treatment under IL50 was referred to as ½ NSc, ½ NS1, and ½ NS2. The findings showed that almost all of the traits studied were significantly affected by the applied treatments. The highest yield (409.4 g m−2), leaf area (34.67 cm−2 plant), biomass (1.092 g−1 plant), membrane stability index (90.47%), chlorophyll a (0.99 mg g−1 FW), chlorophyll b (0.413 mg g−1 FW), total chlorophyll (1.54 mg g−1 FW), carotenoid (0.437 mg g−1 FW), vitamin C (730.7 mg ascorbic acid kg−1 FW), amino acid (236.8 µg g−1 FW) and nitrate reductase activity (102.8 µg NO2 - mg Protein−1 h−1) were observed in NSc + HA. In addition, the highest carbohydrate (46.99 mg g−1 FW), phenol (1129 mg GAE Kg−1 FW), and flavonoid content (1133 mg Catechin Kg−1 FW) and antioxidant activity (74.75%) were observed in ½ NS1 + HA. In addition, the highest relative water content (86.62%) and nitrate content (1106 mg kg−1 FW) were recorded in NS2 + HA and NSc, respectively. The application of HA combined with different concentrations of the nutrient solution under both irrigation levels caused an increase in most of the parameters studied in rocket plants compared to respective treatments without HA application. In addition, the results obtained confirmed that HA could compensate for the stress caused by a shortage of nutrients and water in the nutrient solution in this crop.

Manganese sulfate application promotes berry flavonoid accumulation in Vitis vinifera cv. 'Cabernet Sauvignon' by regulating flavonoid metabolome and transcriptome profiles.

Flavonoids are vital for developing grapes and wine quality, and manganese deficiency decreases grape berry coloration. However, the effects and underlying mechanisms of action of manganese sulfate on grape metabolic profiles have not been well studied. In this study, three concentrations of manganese sulfate solutions: 0.5 μmol·L-1 (low, L), 5 μmol·L-1 (middle, M, the standard manganese concentration of Hoagland nutrient solution, control), and 1000 μmol·L-1 (high, H) were applied to "Cabernet Sauvignon" grapevine (Vitis vinifera L.) to explore the effect on berry composition. Manganese application effectively improved manganese concentration in grape organs. Furthermore, the concentrations of malvidin 3-O-(6-O-acetyl)-glucoside, malvidin 3-O-glucoside, malvidin-trans-3-O-(6-O-p-coumaryl)-glucoside, and peonidin 3-O-(6-O-acetyl)-glucoside were significantly increased under H treatment. More importantly, weighted gene co-expression network analysis (WGCNA) revealed that the structural genes (VvDFR, VvUFGT, and VvOMT) of flavonoid biosynthesis in brown module were upregulated under H treatment, and positively correlated with malvidin- and peonidin-derived anthocyanin concentrations. This study suggested that manganese application regulates berry transcriptional and flavonoid metabolic profiles, providing a theoretical basis for improving the color of red grapes and wines. This article is protected by copyright. All rights reserved.

Morphophysiology, biochemical, and yielding characteristics of Chinese cabbage due to formulation and concentration of nutrient solution in hydroponic culture

Hydroponic solution from agricultural organic waste can be used as an alternative to chemical solutions and strongly increases the growth and yield of Chinese cabbage plants. This study was to obtain formulations, concentrations, and their interactions that have the potential to increase the agronomic, physiological, biochemical, and yielding characteristics of Chinese cabbage in hydroponic culture. This study was conducted from September to November 2022 using a randomized block design with two factors and three replications. The first factor was the formulation of organic nutrient solutions (F1= banana peels+bean sprouts+eggshells; F2= banana humps+onion peels+bean sprouts+moringa leaves; F3= moringa leaves+onion peels+bean sprouts; F4=AB mix as a comparison). The second factor was the concentrations (600; 900; 1,200; 1,500 ppm). Data were analyzed using ANOVA and proceeded with the Duncan at P<0.05. The results showed that formulations F3 and F2 significantly increased Mg and chlorophyll b levels while formulation F1 increased nitrate and flavonoids. The concentrations ranged from 1,200 to 1,500 ppm showed the highest yield and shoot fresh weight were 2.86 kg m-2 year-1 and 30.70 g. The F3C4 interaction was highly recommended to increase the yield of Chinese cabbage by 2.68 kg m-2 year-1 compared to the other liquid organic fertilizers and it could be used as a substitute for using liquid chemical fertilizers in hydroponic culture.

Yield, nutrition, and leaf gas exchange of lettuce plants in a hydroponic system in response to Bacillus subtilis inoculation.

Inoculation with Bacillus subtilis is a promising approach to increase plant yield and nutrient acquisition. In this context, this study aimed to estimate the B. subtilis concentration that increases yield, gas exchange, and nutrition of lettuce plants in a hydroponic system. The research was carried out in a greenhouse in Ilha Solteira, Brazil. A randomized block design with five replications was adopted. The treatments consisted of B. subtilis concentrations in nutrient solution [0 mL "non-inoculated", 7.8 × 103, 15.6 × 103, 31.2 × 103, and 62.4 × 103 colony forming units (CFU) mL-1 of nutrient solution]. There was an increase of 20% and 19% in number of leaves and 22% and 25% in shoot fresh mass with B. subtilis concentrations of 15.6 × 103 and 31.2 × 103 CFU mL-1 as compared to the non-inoculated plants, respectively. Also, B. subtilis concentration at 31.2 × 103 CFU mL-1 increased net photosynthesis rate by 95%, intercellular CO2 concentration by 30%, and water use efficiency by 67% as compared to the non-inoculated treatments. The concentration of 7.8 × 103 CFU mL-1 improved shoot accumulation of Ca, Mg, and S by 109%, 74%, and 69%, when compared with non-inoculated plants, respectively. Inoculation with B. subtilis at 15.6 × 103 CFU mL-1 provided the highest fresh leaves yield while inoculation at 15.6 × 103 and 31.2 × 103 CFU mL-1 increased shoot fresh mass and number of leaves. Concentrations of 7.8 × 103 and 15.6 × 103 increased shoot K accumulation. The concentrations of 7.8 × 103, 15.6 × 103, and 31.2 × 103 CFU mL-1 increased shoot N accumulation in hydroponic lettuce plants.

Effect of nutrient solution concentrations on the growth and yield of potato (Solanum tuberosum L.) varieties grown from apical rooted cutting in a hydroponic system

This study evaluated the effects of nutrient stock solution concentrations on the growth and yield of potato varieties grown from apical rooted cuttings (ARCs). A greenhouse experiment was conducted at the Climate and Water Smart Agriculture Center at Egerton University, Kenya. The experiment was laid out in a split-plot arrangement in randomized complete block design, where the main plot comprised three nutrient concentrations, i.e., 75% (N75), 100% (N100) and 125% (N125) of the ADC-Molo’ nutrient formulation. The subplots were allocated to four potato varieties (Shangi, Wanjiku, Nyota and Unica). The results showed that there were no significant (p<0.05) interaction effects of the nutrient stock solution concentrations application rates on the growth attributes of ARCs. The main effects of N125 gave the tallest plants (32.29cm) at 60 days after planting (DAP), highest normalised difference vegetation index (NDVI) (0.60) at 75 DAP, plant survival rate (82.15%) at 75 DAP, and fresh weight (79.04g) and dry matter (31.26%) of aboveground biomass (AGB). Nyota variety produced taller plants (26.90cm) at 60 DAP, gave higher NDVI values (0.53) at 75 DAP, and higher fresh weight (64.87g) and dry matter (27.60%) of the AGB. Significant (p<0.05) interactions were observed in the yield parameters. The interaction between N125 and Nyota (11.33) and Wanjiku (10.67) gave the highest number of minitubers, the highest yields were obtained between the interaction of N125 and Unica (16.38t/ha). Therefore, to achieve high growth and yields of ARCs under hydroponic system, seed potato producers should use 125% of the ADC Molo nutrient formulation.

Growth, biochemical and physiological response of grapevine rootstocks to copper excess in nutrient solution

Frequent applications of cupric fungicides on grapevines increase copper (Cu) content in vineyard soils, and can lead to phytotoxicity, mainly in young grapevines. Thus, is necessary to identify rootstocks that are tolerant to Cu excess, as well as understanding the mechanisms against high Cu concentrations. The aim of this study was to assess the growth, biochemical and physiological response of grapevine rootstocks to Cu excess in nutrient solution. Two experiments were carried out: Experiment 1 used Vitis rotundifolia cv. Magnolia rootstocks and Experiment 2 used Paulsen 1103 (Vitis berlandieri X Vitis rupestris) rootstocks. The rootstocks were cultivated with different Cu concentrations in nutrient solution (in µM): 0.12; 20; 40 and 80. The high Cu concentrations had negative effect on growth of both grapevine rootstocks. The highest Cu concentrations were observed in roots in both rootstocks. Magnolia rootstock showed the greatest tolerance to Cu excess in nutrient solution, with less absorbed Cu as well as less Cu translocation to shoots. Hydrogen peroxide concentrations and lipid peroxidation increased in shoots and roots of both rootstocks with increased Cu concentrations. The size and rusticity of Magnolia plants may have influenced their response to the excess of Cu in the solution in comparison to Paulsen plants.

Response of cucumber (Cucumis sativus L. ‘Kiara’) plants, grown on own root or grafted onto different rootstocks, to high nutrient solution concentrations

Response of cucumber (<i>Cucumis sativus</i> L. ‘Kiara’) plants, grown on own root or grafted onto different rootstocks, to high nutrient solution concentrations

Balancing Yield and Antioxidant Capacity in Basil Microgreens: An Exploration of Nutrient Solution Concentrations in a Floating System

The appropriate concentration of the nutrient solution (NS) plays an important role in the yield, antioxidant capacity, and biochemical compounds of basil microgreens in the floating system. This study examined the impact of five different concentrations of Hoagland’s NS (25%, 50%, 75%, 100%, and 125%) on the antioxidant capacity, biochemical compounds, and yield of four basil cultivars and genotypes (Persian Ablagh, Violeto, Kapoor and Red Rubin) in a floating system, utilizing a split plots designs. Results revealed that the highest yield was achieved with a 50% NS concentration. The Persian Ablagh genotype, under a 125% NS concentration, exhibited the highest content of carotenoids, flavonoids, phenolic compounds, and antioxidant potential index (APCI). The Violeto cultivar at a 100% NS concentration produced the highest amounts of vitamin C and anthocyanin. The Kapoor cultivar, when grown with a 100% NS concentration, demonstrated the greatest antioxidant capacity. The nutrient solution with 125% concentration compared to 50% concentration reduced the yield by 23.29%. Also, the performance of the Violeto cultivar increased by 36.24% compared to the red variety of Robin. According to the APCI index, the genotype of Iranian Ablaq basil increased by 152.79% in the treatment of nutrient solution with a concentration of 125% compared to 50%. In this study, yield and total chlorophyll showed a significant negative correlation. A significant positive correlation was observed between vitamin C content and flavonoids, anthocyanin, phenolic compounds, and antioxidant capacity. Anthocyanin content exhibited a positive and significant correlation with the APCI. Based on these findings, we recommend a 50% NS concentration of Hoagland’s NS for optimal yield, a 125% NS concentration for the production of secondary metabolites with enhanced antioxidant capacity, and a 100% NS concentration as a balance between antioxidant properties and yield for basil microgreens production in a floating system.

The Electrical Conductivity and Drying Method Changed the Secondary Metabolite Content and Photoprotective Effects of Hydroponically Cultivated Agastache rugosa Kuntze

Many studies have examined how various cultivation methods and elicitors elevate target crop values. Post-harvest treatments, such as the drying method, may alter the final product’s characteristics. We investigated the effect of nutrient solution concentration during the hydroponic cultivation and drying method (cold air drying and freeze drying) after harvesting Agastache rugosa Kuntze, an herb used for folk medicine and as a deodorant, spice, and tea in East Asia. To explore the properties of A. rugosa, we determined its growth parameters, secondary metabolites, and photoprotective effects. We observed the highest growth and yields in A. rugosa grown under 4.0 dS·m−1 electrical conductivity (EC) conditions. However, the EC 2.0 group showed higher antioxidative properties than those grown in EC 1.5 and 4.0 conditions. Drying conditions varied the content and ratios of major active compounds (rosmarinic acid, tilianin, and acacetin) in A. rugosa. Cold air drying caused rosmarinic acid transmutation to tilianin and acacetin, and tilianin showed a stronger positive correlation with antioxidative and photoprotective activities than rosmarinic acid. The increased tilianin content in cold-air-dried A. rugosa accompanied the improved photoprotective effects in dermal cell lines. This study reveals the effects of cultivation and drying methods in A. rugosa production, and proposes alternate industrial production techniques.

Research on artificial neural networks to accurately predict element concentrations in nutrient solutions

Calcium, potassium, nitrogen, magnesium, and phosphorus, the main elements of the nutrient solution, are absorbed by plants and play an important role in plants. By measuring Ca2+, K+, Mg2+, NH4 +, NO3 −, HPO4 2−, the artificial neural networks (ANNs) were used in this study to accurately calculate the concentrations of these elements. Firstly, the error sources of the calculating element concentration were analyzed based on the data of six-ion measurement experiments. Subsequently, various optimization algorithms were compared to optimize back propagation and radial basis function ANNs. Finally, the results of mean relative errors (MREs) and recovery values show that ANNs can effectively reduce the measurement error of ion sensors. From the perspective of recovery values, the prediction error of all elements can be controlled within 15%. From the perspective of MRE, except for magnesium and phosphorus elements, the improved model prediction errors of other elements were also less than 10%.

Performance analysis of two typical greenhouse lettuce production systems: commercial hydroponic production and traditional soil cultivation.

Due to the shortage of land and water resource, optimization of systems for production in commercial greenhouses is essential for sustainable vegetable supply. The performance of lettuce productivity and the economic benefit in greenhouses using a soil-based system (SBS) and a hydroponic production system (HPS) were compared in this study. Experiments were conducted in two identical greenhouses over two growth cycles (G1 and G2). Three treatments of irrigation volumes (S1, S2, and S3) were evaluated for SBS while three treatments of nutrient solution concentration (H1, H2, and H3) were evaluated for HPS; the optimal levels from each system were then compared. HPS was more sensitive to the effects of environmental temperature than SBS because of higher soil buffer capacity. Compared with SBS, higher yield (more than 134%) and higher water productivity (more than 50%) were observed in HPS. We detected significant increases in ascorbic acid by 28.31% and 16.67% and in soluble sugar by 57.84% and 32.23% during G1 and G2, respectively, compared with SBS. However, nitrate accumulated in HPS-grown lettuce. When the nutrient solution was replaced with fresh water 3 days before harvest, the excess nitrate content of harvested lettuce in HPS was removed. The initial investment and total operating cost in HPS were 21.76 times and 47.09% higher than those in SBS, respectively. Consideration of agronomic, quality, and economic indicators showed an overall optimal performance of the H2 treatment. These findings indicated that, in spite of its higher initial investment and requirement of advanced technology and management, HPS was more profitable than SBS for commercial lettuce production.

Effective nutrient removal using nutrient film technique hydroponics unit under varying nitrate nitrogen concentrations

AbstractSurface and groundwater are both susceptible to nitrate nitrogen contamination that has emerged as an issue around the globe in past few years. The main goal of this research was to treat nitrate‐contaminated water through phytoremediation in a hydroponic system with reduced cost and also assess the root and shoot growth of plants cultivated in NFT hydroponic systems. Four different nitrate‐nitrogen concentrations (30, 60, 90, and 120 mg/L) were given to hydroponic treatment unit. The results revealed that shoot growth, root growth, leaf number, and shoot numbers were increased with increasing nutrient solution concentration. The study's findings demonstrated that the average elimination efficiencies of nitrate‐nitrogen varied from 44.5% to 88% for money plants, 30.77% to 80.66% for crotons, 42.56% to 86% for arrowhead plants, 32.03% to 72.25% for vetiver grass, 28.08% to 70% for spinach, and 38.11% to 75.5% for brinjal plants, respectively. Thus, hydroponic phytoremediation has emerged as the environmental and cost‐effective technique for diminishing and removing nitrate nitrogen from wastewater.