Nutrient Solution Management Research Articles

Assessing the Capabilities of UV-NIR Spectroscopy for Predicting Macronutrients in Hydroponic Solutions with Single-Task and Multi-Task Learning

Macronutrients, including nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S), are the most basic nutrient elements in the solution for the hydroponic system. However, the current management of hydroponic nutrient solutions usually depends on EC and pH sensors due to the lack of accurate specific macronutrient sensing equipment, which easily leads to nutritional imbalance for the cultivated plant. In this study, the UV-NIR absorption spectroscopy (200–1100 nm) was used to predict six macronutrients in hydroponic solutions; two kinds of single-task learning algorithms, including partial least squares (PLS) and least absolute shrinkage and selection operator (LASSO), and two kinds of multi-task learning algorithms, including dirty multi-task learning (DMTL) and robust multi-task learning (RMTL), were investigated to develop prediction models and assess capabilities of UV-NIR. The results showed that N and Ca could be quantitatively predicted by UV-NIR with the ratio of performance to deviation (RPD) more than 2, K could be qualitatively predicted (1.4 < RPD < 2), and P, Mg, and S could not be successfully predicted (RPD < 1.4); the RMTL algorithm outperformed others for predicting K and Ca benefit from the underlying task relationships with N; and predicting P, Mg, and S were identified as irrelevant (outlier) tasks. Our study provides a potential approach for predicting several macronutrients in hydroponic solutions with UV-NIR, especially using RMTL to improve model prediction ability.

Investigation of nutrient solution management in hydroponics using organic fertilizer

Investigation of nutrient solution management in hydroponics using organic fertilizer

Greenhouse farming: Hydroponic vertical farming- Internet of Things (IOT) Technologies: An updated review

This review paper of literature highlights the importance of greenhouse urban farming technology, hydroponics, aeroponics, aquaponics, vertical farming and applications of Internet of Things (IOT) technologies. The greenhouse farming is a well known modern agriculture technology for optimal plant growth. Hydroponics, a soilless cultivation technique using nutrient solutions under controlled conditions, is used for growing vegetables, high-value crops, and flowers. Vertical farming is a popular trend in hydroponics that involves stacking multiple layers of plants in a vertical arrangement. This farming method saves space, reduces water usage, and increases yields per square foot of growing area. In comparison to conventional greenhouse cultivation, hydroponics requires less fertilizer, pesticides, and water due to the precise control over their distribution. The term “Internet of Things (IOT)” is a system of interconnected computing devices, sensors, objects, microcontrollers, and cloud servers that can transmit data across a network and control other devices remotely without human intervention. A better management of nutrient solution in hydroponic systems requires optimum pH, electrical conductivity (EC), or ions concentration. The three main greenhouse farming gases (GHGs) emissions in hydroponics hi-tech urban farming are nitrous oxide, methane and carbon dioxide (CO2). To measure the levels of CO2 in hydroponics, the more intermediate to advanced grower can use a CO2 monitoring and controllers system. Hydroponic vertical farming is in infancy in India. Although hydroponic vertical farming units for production of crops like strawberry, lettuce and other leafy vegetables, foliage and flowers are functioning in major metros of India. However, the organized hydroponic vertical farms for production of food crops are not available in India. Therefore, only a few successful hydroponic vertical farms have been built in India mainly due to the initial high price tag on construction and the cost of maintaining them afterwards. Another disadvantage is carbon footprint of hydroponic vertical farming is very high, and discourages its applications.

Strawberry growth and dry matter partitioning due to fertigation systems

Strawberry cultivation possesses unique features, including the need for high-quality seedlings adapted to the cultivation environment and proper fertigation management. These elements influence plant growth and production. This study evaluated the growth and dry matter partitioning of strawberry plants of the cultivar "Albion" at different seedling ages (0, 14, 28... 196 DAT) using two fertigation methods: open-loop and closed-loop systems. Fifteen evaluations occurred throughout the cultivation cycle, spanning from planting to 196 days after transplanting (DAT), with the study replicated over two consecutive years. We evaluated dry matter partitioning among roots, stems, leaves, senescent leaves, flowers, commercial fruits, and non-commercial fruits. We also measured root volume and length, besides counts of leaves, flowers, and both commercial and non-commercial fruits. Despite no significant differences between fertigation systems for most variables, the closed-loop system shows promise, contingent on proper nutrient solution management. The partitioning analysis revealed that fruits, followed by leaves, were the primary consumers of photoassimilates.

Evaluating temperature variation of nutrient solution in Nutrient Film Technique (NFT) cooling system for temperate vegetable

The production of leafy green vegetables in hydroponic systems within greenhouses has gained global prominence in the fresh vegetable production industry. Hydroponic systems, particularly Nutrient Film Technique (NFT), are highly effective due to their soilless nature and efficient nutrient and water circulation. However, maintaining ideal greenhouse temperatures can be challenging. One strategy to reduce energy costs is to heat or cool the nutrient solution instead of the entire greenhouse environment. By regulating the root zone temperature through nutrient solution management, growers can provide more favourable conditions for temperate leafy greens. These conditions are critical because temperatures above 23°C can inhibit plant growth, while temperatures exceeding 35°C can significantly reduce plant metabolism efficiency. This study investigates how lettuce responds to nutrient solution cooling. Importantly, this research focuses on Malaysia, an equatorial country with a consistently warm and humid climate. In such environments, controlling nutrient solution or air temperature to match the crops' optimal growth requirements is crucial. The study employed Butterhead and Romaine lettuce varieties in a hydroponic NFT system. The EC (Environmental Cooling) treatment involved cooling the nutrient solution, while the RZC (Root Zone Cooling) treatment utilized environmental cooling. The results demonstrated that maintaining a consistent nutrient solution temperature within the range of 14°C to 18°C (as observed in the EC treatment) led to superior plant growth and quality, particularly in the early growth stages. In contrast, the RZC treatment showed temperature fluctuations, causing plant stress and inhibiting growth.

Reducing nitrate accumulation through the management of nutrient solution in a floating system lettuce (Lactuca sativa, L.)

Lettuce is a leading greenhouse-grown vegetable highly appreciated by consumers for its nutritional properties texture and flavor. However, leafy vegetables are known to accumulate an excessive amount of nitrate and this constitutes a strong health concern in Europe. Among the factors that most affect the yield and quality of hydroponic crops, the composition and management of the nutrient solution stand out. In this work, different strategies have been studied in the management of the nutrient solution for hydroponic lettuce cultivation. Production nutritional status, and quality parameters were evaluated. The concentrations of nutrients in the nutrient solution significantly influence the harvested product, 100 to 50 % H treatment resulted in highest yields with significant increase of 14 % compared to 50 % H at 34 DAT, from the point of view of both biomass production and quality, regarding the contents of anthocyanins, chlorophylls, and calcium, constituents that add value to the product due to their importance in the human diet. A significant reduction of nitrates in lettucewas observed one (14 %) and two (22 %) weeks after modifying the nutrient solution (100 to 50 % H). After one week there was no reduction in lettuce growth. In addition, no significant reduction in the concentration of most macro- and micronutrients was observed.

The efficiency of adjusting nutrient solution renewal frequency on physicochemical properties and microbial community of cucumber exudates under closed cultivation tank.

The closed nutrient solution management method allows for the recycling and utilization of nutrient solutions, improving the efficiency of water and fertilizer utilization. This study was conducted to investigate the effects of changing the frequency of nutrient solution renewal and method of nutrient supply on the microbial communities composition, yield, and quality in closed soilless systems by using high-throughput sequencing technology and combining the physicochemical properties of root exudate solution. The results showed that different nutrient solution management modes had a significant impact on the structure and diversity of root exudate solution microbial communities. The abundance and diversity of microorganisms in inorganic perlites were correlative with EC. The abundance and diversity of bacterial communities in the root exudate solution of open liquid supply (CK) were higher than that of closed liquid supply, while the abundance and diversity of fungal communities in the root exudate solution of closed liquid supply (T1, T2, T3) were higher than that of open liquid supply. As the frequency of nutrient solution interval decreased, the accumulation of salt in root exudate solution and the richness and diversity of the fungal community also decreased, especially increasing the K+, Ca2+, and Mg2+ contents, which were positively correlated with potential beneficial Candidatus_Xiphinematobacter, Arachidicoccus, Cellvibrio, Mucilaginibacter, Taibaiella communities and decreasing the content of soluble protein, Vitamin C content, but not significantly increased cucumber yield.

Optimal nutrient solution management program for Cucumis melo L. growth by using a comprehensive evaluation method

Optimal nutrient solution management program for Cucumis melo L. growth by using a comprehensive evaluation method

Current perspective on nutrient solution management strategies to improve the nutrient and water use efficiency in hydroponic systems

Hydroponics, a soilless cultivation technique using nutrient solutions under controlled conditions, is used for growing vegetables, high-value crops, and flowers. It produces significantly higher yields compared to conventional agriculture despite its higher energy consumption. The success of a hydroponic system relies on the composition of the nutrient solution, which contains all the essential mineral elements necessary for optimal plant growth and high yield. This review delves into the discussion of enhancing nutrient solution management strategies across different hydroponic systems. The aim of this review is to discuss various techniques for monitoring nutrient solutions in order to improve nutrient use efficiency (NUE) and water use efficiency (WUE). The conventional approach of monitoring the hydroponic nutrient solution using electrical conductivity measurement may not provide precise information about ion concentrations, potentially resulting in poor yields or excessive fertilizer usage. To overcome these limitations, alternative management strategies have been developed to enable more accurate monitoring and efficient management. One such strategy is the nitrogen-based approach, where nitrogen concentration becomes the primary controlled element in the nutrient solution and leads to WUE and NUE development by prolonging nutrient solution recirculation. Furthermore, various methods have been devised to improve nutrient solution strategies. These include using ion-selective electrodes to measure individual ions in the hydroponic nutrient solution, using sensors to monitor substrate moisture content, estimating water requirements, and implementing programmed nutrient addition methods. In addition to introducing different management techniques to optimize hydroponic performance, this review provides a better understanding of hydroponic systems.

Substrate and fertigation management modulate microgreens production, quality and resource efficiency

Long-term space missions will require a self-sustaining food production system to meet the crew’s nutritional and health needs. For this purpose, plant-based food production systems with elevated resource efficiency are required, based on advanced agricultural technologies that produce phytonutrient-rich crops. In addition to the resource requirements for crop production on Earth, volume and time efficiency become essential factors to consider for food production in space. Microgreens represent a promising candidate for space farming as they have a high harvest index, short cultivation cycle, and high nutritional potential. However, the development of specific technical protocols for growing microgreens in space is essential since different agronomic inputs, such as substrates and fertigation, can modulate productivity, quality and resource efficiency of microgreens cultivation. The current work examines the effects of different substrates (coconut fiber and cellulose sponge) and nutrient solution (NS) management strategies (quarter strength Hoagland and half strength Hoagland/osmotic water) on the production of two species of microgreens [Raphanus sativus cv. Saxa 2 (Radish); Brassica oleracea var. capitata f. sabauda cv. Vertus (Savoy cabbage)]. The appraisal focused on (i) biomass production and quality, and (ii) sizing of space facilities devoted to the production of phytonutrients required for the astronauts’ wellbeing. In our study, the interaction among species, substrate and NS significantly affected the accumulation of fructose, sucrose, total soluble non-structural carbohydrates and nitrate as well as the daily production of total ascorbic acid and, in turn, the required microgreens serving to supply its adequate daily intake. Species-substrate interaction effects on fresh yield, dry yield, dry matter, anthocyanins, TPC, β-carotene and sulfate content as well as the cultivation surface required to produce the adequate daily intake of ascorbic acid (AscA) were assessed. Substrate-NS interaction modulated the anthocyanins, violaxanthin and sulfate contents independently of species. On the other hand, single factor effects were identified with respect to the accumulation of lutein, chlorophylls, glucose, and starch. Therefore, the management of microgreens cultivation in terms of NS and substrate is an effective tool to meet the phytochemical requirements of the crew.

Assessing the reliability of portable ion-selective electrodes proposed for the on-farm management of nutrient solutions and fertigation of horticultural crops

Assessing the reliability of portable ion-selective electrodes proposed for the on-farm management of nutrient solutions and fertigation of horticultural crops

Technology development and industrialization trends of circulating nutrient solution supply systems: a review

Hydroponics, a soil-free plant cultivation technique, delivers nutrients directly to roots through a nutrient-rich solution. This method offers advantages over traditional soil-based approaches and has gained attention for its potential to revolutionize controlled agriculture. The review aimed to offer a summary of technological advancements and industrialization patterns in systems supplying circulating nutrient solutions. An intelligent nutrient management system enhances plant growth and productivity. The utilization of a circulating hydroponic cultivation setup can reduce environmental pollution and lower production expenses. As a result, circulating nutrient solution management systems are gaining global popularity, such as in the Netherlands, circular hydroponic cultivation has been advanced to over 95%. A limitation of circulation-type nutrient solution cultivation is the potential transmission and rapid formulation of pathogens during the recycling of discharged nutrient solutions. Addressing this concern, filtration and sterilization processes can offer viable solutions. To accelerate hydroponic farming, an integrated approach could be pursued, strengthen nutrient circulation management technology. This approach could aid in the implementation of such systems in countries like the Republic of Korea, where adoption of circulating hydroponic systems remains under 5%. The trend of technological advancement and industrial growth has been conducted through patent analysis and resources that have subsequently lead the way for the advancement of extensive hydroponic farming establishments. The cyclic hydroponic cultivation in the Republic of Korea was introduced in 2010, and based on the patent information, this endeavor gained momentum from 2020 onward. Furthermore, the analysis underscores the considerable potential of circulating nutrient solution supply systems as viable approaches for promoting sustainable and efficient food production. As a result, forthcoming research and innovation need to be tailored to the local context and prioritize user-centered methodologies, ultimately facilitating the integration and establishment of hydroponic systems in the Republic of Korea.

Response of Shoot and Root Growth, Yield, and Chemical Composition to Nutrient Concentrations in Soybean Varieties Grown under Soilless and Controlled Environment Conditions

The practice of cultivating crops in a controlled environment using a soilless culture method is seeing an increasing level of popularity. The aforementioned challenges include addressing climate change, combating pests and diseases, mitigating falling soil fertility, and ensuring constant production and quality. One of the potential crops that could be grown with such a method is soybean. Soybean cultivation in a controlled environment using soilless culture still needs more information, especially regarding nutrient solution management of certain soybean varieties. Thus, this study investigated the impact of nutrient concentrations and variety on soybean growth, yield, and chemical composition. This research was carried out in a plant growth chamber using expanded clay aggregate as a soilless substrate. The treatments were four nutrient concentrations: 0% (control), 50%, 100%, and 150%, and two different varieties: Martina and Johanna. The findings of this research revealed that there were significant differences in nutrient treatments on all parameters measured. Application of nutrient concentration at 50% resulted in the most profound root size for both varieties. Applying 100% nutrient concentration produced a higher 100-grain weight for the Johanna variety. Application of nutrient concentration at 150% resulted in the highest shoot weight and shoot:root ratio for both varieties, with varietal differences. Furthermore, applying nutrient concentration at 150% also produced the highest grain yield/pot, protein yield, and lipid yield for both varieties. Thus, the nutrient concentration between 100% and 150% gave a positive effect and can be applied for planting Martina and Johanna using this system.

Effects of nutrient solution management modes on fruit production and quality of tomatoes grown in extremely root restriction

Tomatoes (Solanum lycopersicum L.) are popular worldwide due to their unique flavor and abundant nutrients. To explore a suitable nutrient solution management mode for high quality production of tomato grown in extremely root restriction, we analyzed the effect of drainage rate and electric conductivity (EC) of nutrient solution on plant growth and fruit production of tomatoes. To reveal the diversity of flavor in tomato fruits under four modes, we focused on sugars, organic acids, amino acids, fatty acids and volatile compounds. In total, 831 metabolites were identified by metabolome analysis. The results displayed that low drainage (0–5%) significantly repressed plant growth, reduced photosynthesis and fruit production. Normal drainage (20%) combined with high EC markedly promoted the accumulation of soluble sugar and most of aromatic amino acids as well as fatty acids. The treatment of increasing EC by adding NaCl (EC1.2/4.8(1.2+3.6Na)/3.2(1.2+2.0Na)) markedly promoted the level of 5 compounds of (glucose-1p, glucose-6p, glyceric acid-3p, phosphoenolpyruvate and sedoheptuiose-7p), 1 compound (α-ketoglutaric acid) involved in tricarboxylic acid cycle and 1 volatile (2-phenylethanol). Therefore, the increase of EC from 1.2 to 4.8 dS/m by adding NaCl is an ideal pathway to ensure fruit production and high-quality tomatoes grown in extremely root restriction.

基于随机森林算法的整株水培生菜缺素诊断

The phenotypic information of lettuce leaves can well reflect its health. In order to diagnose the nutrient deficiency types of hydroponic lettuce accurately, non-destructively and quickly in the mid-growth stage, a method for diagnosis of whole lettuce based on random forest algorithm (RF) was proposed. The images of lettuce under four different conditions, K-deficiency, Ca-deficiency, N-deficiency and Normal, were collected and segmented by Extra-green algorithm. Then, features of color, texture and shape were extracted. A RF classification model for the hydroponic lettuce nutrient deficiency diagnosis was constructed and compared with support vector machine (SVM) and back propagation neural network (BP). RF had the best classification effect among the three methods. The overall classification accuracy was 86.32%, Kappa coefficient was 0.82, and it can provide a basis for the prevention and remedies of lettuce deficiency and the scientific management of nutrient solutions.

Soilless cultivation of ‘Ruby Star’ passion fruit: Effects of NO3-N application, pH, and temperature on fruit quality

• Passion fruit water uptake increased up to 32 L plant –1 week –1 at harvest time. • NO 3 -N absorption ranged from 203 to 267 mg plant –1 day –1 during flowering and harvest. • NO 3 -N concentration of 170 ppm and pH 4–5 result in optimal fruit quality. • High temperature delayed fruit maturity and decreased fruit sugar content and acidity. • Optimal daily mean temperature for producing high-quality fruit was 27–29°C. This study aimed to develop a nutrient solution management protocol to produce a high quality passion fruit using soilless culture. In this study, a two-year experiment was conducted using three levels of electrical conductivity (EC) (1.6, 2.0, and 2.6 dS m –1 ) of the nutrient solution in the first year, and three levels of pH (4, 5, 6) of the nutrient solution in the second year. Although no significant differences were detected in the above-ground dry matter weight, yield, and total soluble solids (TSS) of fruit juice of plants cultivated under different EC and pH conditions, dry matter weight tended to increase under pH 4 condition. The total NO 3 -N absorption increased in plants cultivated in EC 2.6, whereas absorption after pruning back the fruit-bearing vines was not significantly different as affected by EC 2.0 or EC 2.6. A nutrient solution with EC 2.0 and pH 4–5 containing 170 ppm NO 3 -N was found to be optimal for fruit quality. Higher air temperatures delayed fruit maturity and decreased TSS and titratable acidity of the juice, indicating that the optimal daily mean temperatures after flowering were 27–29°C for reliably producing high-quality fruit with a high sugar/acid ratio (≥6.0).

Sweet basil can be grown hydroponically at low phosphorus and high sodium chloride concentration: Effect on plant and nutrient solution management

Agronomic inputs in agriculture easily exceed crop needs causing environment pollution. Phosphorus (P) is a macronutrient largely used in agriculture as a mineral fertilizer that requires an accurate management because it is a finite and non-renewable resource. Growing plants hydroponically can optimize plant nutrition achieving high crop nutrient use efficiency. However, irrigation water of poor quality (saline) interferes with crop performance. In this study, the effects of different P and NaCl levels in the root zone were evaluated on basil plants grown in a deep liquid culture system in a growth chamber. Two experiments with different P (from 0.1 to 1.0 mol m−3) and NaCl (from 0 to 60 mol m−3) concentrations in the nutrient solution were carried out. Plant growth, leaf gas exchanges and fluorescence, uptake of minerals and water, and leaf quality (content of minerals and pigments, and antioxidant capacity) were analysed. The most relevant morphological plant response to the low P (i.e., roughly 0.1 x of a standard nutrient solution) concentration consisted in a greater root/shoot ratio. However, plants growing at low P concentration did not show any reduction in yield and quality. Sodium chloride did not significantly affect plants yield and quality up to a concentration of 30 mol m−3 confirming the tolerance of basil to moderate saline stress. Significant reduction in the total biomass, water uptake and photosynthesis instead occurred at NaCl 60 mol m−3. These results confirmed the hypotheses that basil can be grown hydroponically at low P and high NaCl concentration with proper management of the nutrient solution. The absence of significant interactions between P and NaCl suggests that these two factors can be managed independently with potential benefits for crop economic and environmental sustainability.

Effect of Chitosan-Poly(Acrylic Acid) Complexes and Two Nutrient Solutions on the Growth and Yield of Two Habanero Pepper Cultivars

Chitosan (CS) is a natural polymer used in agriculture as a biostimulant that has been evaluated in different plant models. In this study, we evaluated the effect of the foliar application of chitosan–poly(acrylic acid) complexes (CS–PAA) and two nutrient solutions (A and B) on the parameters of growth and yield of two habanero pepper cultivars (Chichen Itza and Jaguar) in a greenhouse. Over the course of the experiment, eight foliar applications were carried out at 15-day intervals. Our results showed that foliar applications of CS–PAA complexes have a biostimulant effect on the habanero pepper crop by increasing the total dry biomass of the plant and the number of fruits of the two cultivars. Regarding nutrient solutions, the nutrient solution A increased the yield of the Chichen Itza cultivar; this effect was because it had a better balance of potassium and calcium compared to the nutrient solution B. These results provide advances on the use of CS–PAA complexes as a biostimulant and the management of nutrient solutions in the crop of habanero peppers.

Salmonella Enteritidis survival in different temperatures and nutrient solution pH levels in hydroponically grown lettuce

Due to climate change, with contaminated and less fertile soils, and intense weather phenomena, a turn towards hydroponic vegetable production has been made. Hydroponic cultivation of vegetables is considered to be a clean, safe and environmentally friendly growing technique; however, incidence of microbial contamination i.e. foodborne pathogens, might occur, endangering human health. The aim of this study was to investigate the effects of different plant growth stages, pH (values 5, 6, 7, 8) and bacterial inoculum levels (3 and 6 log cfu/mL) on hydroponically cultivated lettuce spiked with Salmonella Enteritidis. The results revealed that the pH and inoculum levels affected the internalization and survival of the pathogen in the hydroponic environment and plant tissue. Younger plants were found to be more susceptible to pathogen internalization compared to older ones. Under the current growing conditions (hydroponics, pH and inoculum levels), no leaf internalization was observed at all lettuce growth stages, despite the bacterium presence in the hydroponic solution. Noticeably, bacteria load at the nutrient solution was lower in low pH levels. These results showed that bacterium presence initiates plant response as indicated by the increased phenols, antioxidants and damage index markers (H2O2, MDA) in order for the plant to resist contamination by the invader. Nutrient solution management can result in Taylor-made recipes for plant growth and possible controlling the survival and growth of S. Enteritidis by pH levels.

Chemical eustress and biofortification: targeted nutrient solution management for enhancing quality in hydroponically grown vegetables

ISHS III International Symposium on Soilless Culture and Hydroponics: Innovation and Advanced Technology for Circular Horticulture Chemical eustress and biofortification: targeted nutrient solution management for enhancing quality in hydroponically grown vegetables