Search Results (249)

Data-driven empirical models, including those based on reaction kinetics, are well-regarded for their ability to make accurate predictions and uncover underlying relationships. While such models have been extensively employed for microbial communities, their use in agricultural populations remains comparatively limited. In this study, researchers analyzed data from hydroponic lettuce cultivation experiments observing nitrogen-, phosphorus-, and potassium-limited growth. Dynamic μ models, which incorporated nutrient-fueled growth and maturity-based rate decay, were adapted to accommodate a variable nutrient supply, as would be expected for nutrient recovery efforts using domestic wastewater. To test these models, researchers analyzed multiple approaches, differing variations in analyses, and other agricultural models against observed biomass measurements. The resulting Dynamic μ biomass models showed significantly less error than all other tested models, were validated against three variable nutrient treatments, and were evaluated against expected wastewater concentrations. Wastewater-cultivated lettuce was predicted to grow between 20 and 72% of fresh mass compared to lettuce grown under ideal nutrient concentrations, and models identified 41.7 days to maximize dry biomass, with a final harvest time of 44.0 days to maximize fresh biomass. Finally, this research demonstrates the application of agricultural modeling for profit estimation and informing decisions on supplemental nutrient use, providing guidance for nutrient recovery from wastewater. Full article

Maintaining optimal pH in hydroponic systems typically requires continuous pH adjustment, increasing both labor and production costs. In regions with alkaline water sources, this challenge is especially critical. Identifying lettuce cultivars tolerant to high pH conditions offers a cost-effective and sustainable alternative to frequent pH buffering. This study evaluated the impact of water pH on growth, water use efficiency (WUE), and nutrient use efficiency (NUE) of lettuce (Lactuca sativa L.) in deep water culture (DWC) hydroponics. A greenhouse experiment was conducted from June to July 2024 using a completely randomized design with four pH treatments: T1 (unbuffered control), T2 (pH 6.3), T3 (pH 7.0), and T4 (pH 8.3). Three lettuce cultivars—Tacitus (L1), Rex (L2), and Rutilai (L3)—were tested, with three replicates per treatment. Results showed that fresh yield was significantly affected by cultivar but not by pH treatment. Rex produced the highest yield, reaching 132 g/plant at pH 7.0, compared to 127 g/plant for Tacitus and 98 g/plant for Rutilai. WUE differed strongly among cultivars, with Rex achieving 68.7 g/L at pH 7.0, which is nearly double that of Rutilai (37.2 g/L). Nitrogen uptake was unaffected by treatment; however, nitrogen NUE differed significantly, with Rutilai recording 12.8 mg N/g fresh weight at pH 8.3, compared to 8.3 mg N/g fresh weight for Rex and 6.7 mg N/g fresh weight for Tacitus. Calcium uptake and NUE were significantly influenced by both pH and cultivar, ranging from 3.2 to 10.7 mg Ca/g fresh weight. These findings suggest that selecting pH-tolerant cultivars plays a more critical role than pH adjustment in determining yield and efficiency in hydroponic lettuce. Choosing pH-tolerant cultivars such as Rex can reduce dependence on chemical buffering, offering a cost-effective strategy for sustainable hydroponic lettuce production in regions with alkaline water sources. Full article

To meet global food demand, agricultural systems must enhance crop performance, productivity, and sustainability. Biostimulants have emerged as a promising strategy, particularly in vegetable production, due to their ability to enhance plant growth and resilience. This study characterized milk-derived protein hydrolysates (MPH) produced from expired milk and evaluated their potential as biostimulants for hydroponic cos lettuce. Hydrolysis of expired milk with hydrochloric acid achieved 94.55% hydrolysis and yielded 80.77% free amino acids. MPH was applied at volumes of 0, 1, 3, and 5 mL L⁻¹ in combination with Hoagland and Arnon nutrient solution. The 1 mL L⁻¹ (MPH1) treatment significantly increased shoot and root biomass and canopy size while reducing nitrate accumulation and enhancing total flavonoid and ascorbic acid content, as well as antioxidant capacity. HPLC analysis showed that MPH1 treatment promoted the accumulation of key metabolites, including vanillic acid, para-coumaric acid, salicylic acid, ferulic acid, gallic acid, syringic acid, quercetin, myricetin, and naringenin. MPH1 improved uptake of phosphorus, potassium, calcium, magnesium, and iron, contributing to mineral biofortification and nutritional quality. These results demonstrate that MPH at 1 mL L⁻¹ is an effective biostimulant, improving yield and quality while reducing nitrate levels in hydroponically grown cos lettuce, offering a sustainable solution for food waste valorization. Full article

By 2030, the world’s population is projected to reach 8.5 billion, posing significant challenges for food production. Traditional agriculture, which requires large amounts of water, soil, and energy, can contribute to the depletion of natural resources and environmental degradation. In this context, organic hydroponic systems emerge as a sustainable alternative, allowing for more efficient, controlled, and resilient production in the face of climate change. In this research, the physical development of romaine lettuce and the physicochemical parameters of the crop water are evaluated as a function of the number of daily recirculations. The crop variables are measured with the help of an intelligent control system, which allows the real-time monitoring of the process variables. The methodological approach is mixed: quantitative, for the recording of physicochemical variables, and qualitative, for the physical analysis of the crop throughout the process, With the experiments conducted it was found that the treatment with four daily recirculations promoted the most significant physiological growth of the plants. Despite having a pH of approximately five and dissolved oxygen of 6 mg/L, this treatment maintained adequate levels of TDS (2050 ppm) and hardness (1000 ppm), favoring the development of the crop. The treatments with less recirculation presented lower growth values. These results suggest that increased recirculation can optimize yields in floating-root hydroponic systems, addressing global food challenges from an environmentally responsible perspective. Full article

This study evaluated the qualitative and quantitative performance of lettuce (cv. Romana) grown using different cultivation systems under Mediterranean greenhouse conditions equipped with photoluminescent glass panels. Five systems were compared: outdoor soil (PSO), indoor soil (PSI), aeroponic (A), hydroponic with inorganic nutrients (HSN), and hydroponic with organic nutrients (HSO). Morphological, physiological, and quality parameters were measured alongside solar irradiance and extended PAR. The results showed that aeroponics significantly outperformed other systems in fresh weight (52.7 g), photosynthetic pigments, and carotenoids, while HSO showed the lowest yield and quality. Although PSO had the highest antioxidant activity and phenolic content, it exhibited poor yield due to lower water use efficiency and light-induced stress. The PCA analysis highlighted distinct groupings among systems, with A linked to yield and pigment concentration, and PSO associated with antioxidant traits. Despite a 44.8% reduction in solar radiation inside the greenhouse, soilless systems—especially aeroponics—proved effective for maintaining high productivity and quality. These findings support the integration of soilless systems and photoluminescent technologies as sustainable strategies for high-efficiency lettuce production in controlled environments. Full article

Traditional soil cultivation of lettuce faces challenges; hydroponic technology offers solutions to improve lettuce production. However, the interrelationships among the root phenotype of lettuce, auxin synthesis and signal transduction, and nutrient solution flow, and their effects on hydroponic lettuce growth remain unclear. We investigated the effects of nutrient solution flow state on lettuce’s early growth, transcriptomic changes, and auxin-related gene expression. Growth indicators were measured 2, 4, and 6 days after transplanting. The shoot and root fresh weights, total root length, and root surface area were significantly higher under the flow treatment than under the non-flow condition. The shoot fresh weight increased by 29, 64, and 31%, respectively, at the three growth stages. A clear distinction was observed between the samples from different treatment groups. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways that were commonly enriched included “Plant hormone signal transduction (auxin)”. Moreover, the significantly enriched Gene Ontology (GO) terms varied across different time points, which vividly reflected the dynamic characteristics of the plant’s response. Genes related to auxin biosynthesis—such as AL3F1, YUC5, and AMI4G—exhibited higher expression levels under the flow treatment. Overall, these results indicate that nutrient solution flow can promote auxin synthesis and signal transduction in early roots of lettuce. Full article

Hydroponic nutrient solution (HNS) has been established as an ideal conduit for pathogen contamination and proliferation. This study evaluated the efficacy of lactic acid bacteria and their metabolites in mitigating the risk of foodborne pathogens in HNS when compared to conventional chemical treatments. Hoagland’s HNS were prepared according to the manufacturer’s instructions and inoculated with Salmonella Typhimurium, Escherichia coli 0157:H7, and Listeria innocua at 10⁵ CFU/mL cell concentration. These nutrient solutions were subjected to treatment with various concentrations of Lactobacillus rhamnosus live cells, a cell-free extract (CFE) of L. rhamnosus metabolites, sodium hypochlorite and peroxyacetic acid at 22 ± 1 °C for up to 96 h using appropriate controls. The survived cells were enumerated on respective selective media at regular intervals. Additionally, the impact of these treatments on lettuce growth and the physico-chemical properties of HNS, such as pH, electrical conductivity, salinity, total dissolved solids, and % lactic acid content, were determined over 21 days using standard procedures. Both S. Typhimurium and E. coli O157: H7, when in combination with L. rhamnosus, remained stable in HNS over a 96 h period, while L. innocua showed a 3-log reduction. Whereas CFE treatment of HNS showed a significant reduction in Salmonella and E. coli O157: H7 (both undetectable after 96 h; LOD: <1 log CFU/mL). Interestingly, L. innocua levels remained stable after CFE treatment. PAA treatments at 12 mg/L notably reduced Salmonella and L. innocua growth, but not E. coli O157:H7. Lettuce plants in untreated control were significantly taller and heavier compared to those treated with CFE. These findings highlight the potential of biological interventions while emphasizing their limitations in hydroponic systems for pathogen control. Full article

The inclusion of the Internet of Things (IoT) in indoor agricultural systems has become a fundamental tool for improving cultivation systems by providing key information for decision-making in pursuit of better performance. This article presents the design and implementation of an IoT-based agricultural system installed in a plant growth chamber for hydroponic cultivation under controlled conditions. The growth chamber is equipped with sensors for air temperature, relative humidity (RH), carbon dioxide (CO₂) and photosynthetically active photon flux, as well as control mechanisms such as humidifiers, full-spectrum Light Emitting Diode (LED) lamps, mini split air conditioner, pumps, a Wi-Fi surveillance camera, remote monitoring via a web application and three Nutrient Film Technique (NFT) hydroponic systems with a capacity of ten plants each. An ATmega2560 microcontroller manages the smart system using the MODBUS RS-485 communication protocol. To validate the proper functionality of the proposed system, a case study was conducted using lettuce crops, in which the impact of different nutrient solution concentrations (50%, 75% and 100%) on the phenotypic development and nutritional content of the plants was evaluated. The results obtained from the cultivation experiment, analyzed through analysis of variance (ANOVA), show that the treatment with 75% nutrient concentration provides an appropriate balance between resource use and nutritional quality, without affecting the chlorophyll content. This system represents a scalable and replicable alternative for protected agriculture. Full article

In this study, we sought to improve the productivity of Far Eastern catfish (Silurus asotus) and tropical eel (Anguilla bicolor), which are high-value fish species in the Republic of Korea, as well as that of associated crops by applying biofloc technology (BFT)-based aquaponics systems. The following three systems were used: the flow-through system (FTS), BFT, and BFT aquaponics system (BAPs). Caipira lettuce (Lactuca sativa) was utilized and hydroponics (HP) was implemented to compare crop productivity. After 42 days of treatment, the BAPs and BFT systems improved fish productivity, with weight gain rates of 134.47 ± 1.80% in BAPs-cat, 130.38 ± 0.95% in BFT, and 114.21 ± 6.62% in FTS for S. asotus, and 70.61 ± 3.26% in BAPs-eel, 62.37 ± 7.04% in BFT, and 47.83 ± 1.09% in FTS for A. bicolor. During the experiment, the total ammonia nitrogen and NO₂⁻-N concentrations were stable in all plots. In the case of NO₃⁻-N, BFT showed an increasing tendency while both BAPs showed a decrease compared with that of the BFT. BAPs-cat (total weight: 224.1 ± 6.37 g) and HP (220.3 ± 7.17 g) resulted in similar growth. However, in BAPs-eel was 187.7 ± 3.46 g due to root degradation. Water content analysis showed that BAPs-cat and BAPs-eel contained sufficient K, Ca, P, and S, which are important for crop growth. Overall, the effect of BAPs on fish growth was higher than that of FTS. This study reveals that integrating BFT with aquaponics improves productivity for high-value fish and associated crops while maintaining stable water quality. This method offers sustainable, efficient production, reduces environmental impact, and provides insights for future research in sustainable aquaculture practices. Full article

The growing demand for food and the environmental impact of conventional agriculture have prompted the search for sustainable alternatives. Phycocyanin (PC) and total phenolic compounds (TPC) extracted from Spirulina platensis have shown potential for the biological control of phytopathogens. The extraction method directly influences the yield and stability of these compounds. This study aimed to establish an efficient extraction protocol for PC and TPC and to evaluate their antimicrobial efficacy in vitro against Colletotrichum orchidearum, Fusarium nirenbergiae, and Alternaria sp. isolated from hydroponically grown lettuce. The phytopathogens were identified based on phylogenetic analyses using sequences from the ITS, EF1-α, GAPDH, and RPB2 gene regions. This is the first report of C. orchidearum in hydroponic lettuce culture in Brazil, expanding its known host range. Extracts were obtained using hydroalcoholic solvents and phosphate buffer (PB), combined with ultrasound-assisted extraction (bath and probe). The extracts were tested for in vitro antifungal activity. Data were analyzed by ANOVA (p < 0.05), followed by Tukey’s test. The combination of the PB and ultrasound probe resulted in the highest PC (95.6 mg·g⁻¹ biomass) and TPC (21.9 mg GAE·g⁻¹) yields, using 10% (w/v) biomass. After UV sterilization, the extract retained its PC and TPC content. The extract inhibited C. orchidearum by up to 53.52% after three days and F. nirenbergiae by 54.17% on the first day. However, it promoted the growth of Alternaria sp. These findings indicate that S. platensis extracts are a promising alternative for the biological control of C. orchidearum and F. nirenbergiae in hydroponic systems. Full article

Contaminated seeds pose a major risk in hydroponic systems, as a single contaminated seed can compromise the entire setup. Effective decontamination strategies are essential to control seed-borne pathogens. Pecan shells, a byproduct comprising nearly 50% of the nut’s weight, have demonstrated antimicrobial properties against key pathogens. This study evaluated pecan shell extract (PSE) as a treatment to inactivate Listeria monocytogenes, Escherichia coli O157:H7, and Pseudomonas spp. on lettuce seeds and its effect on germination. Lettuce seeds were inoculated with L. monocytogenes strains (101 M, V7, LCDC, and Scott A) and treated with PSE (1:10 w/v) either by coating in sodium alginate or priming for 6 h (4 °C or room temperature). Hydropriming was used as a control. Additional trials with E. coli and Pseudomonas spp. tested PSE at 1:10, 1:20, and 1:30 w/v ratios. Priming at refrigeration significantly reduced Listeria levels. E. coli priming treatments showed significant reductions at 1:20 and 1:30 w/v. For Pseudomonas, priming at 1:20 showed the highest reduction. PSE priming also enhanced germination (88.3%), outperforming other treatments. These findings suggest PSE is a sustainable and effective seed treatment to reduce microbial contamination and enhance seed germination in hydroponic systems. Full article

Developing precision models to describe agricultural growth is a necessary step to promote sustainable agriculture and increase resource circulation. In this study, the researchers hydroponically cultivated Bibb lettuce (Lactuca sativa) across a variety of nitrogen, phosphorus, and potassium (NPK)-limited treatments and developed robust data-driven kinetic models observing nutrient uptake, biomass growth, and tissue composition based on all three primary macronutrients. The resulting Dynamic μ model is the first to integrate plant maturity’s impact on growth rate, significantly improving model accuracy across limiting nutrients, treatments, and developmental stages. This reduced error supports this simple expansion as a practical and necessary inclusion for agricultural kinetic modeling. Furthermore, analysis of nutrient uptake refines the ideal hydroponic nutrient balance for Bibb lettuce to 132, 35, and 174 mg L⁻¹ (N, P, and K, respectively), while qualitative cell yield analysis identifies minimum nutrient thresholds at approximately 26.2–41.7 mg-N L⁻¹, 3.7–5.6 mg-P L⁻¹, and 17.4–31.5 mg-K L⁻¹ to produce compositionally healthy lettuce. These findings evaluate reclaimed wastewater’s ability to offset the fertilizer burden for lettuce by 23–45%, 14–57%, and 3–23% for N, P, and K and guide the required minimum amount of wastewater pre-processing or nutrient supplements needed to completely fulfill hydroponic nutrient demands. Full article

A circular tri-trophic system integrating aquaponics, i.e., combined cultivation of crops and fish, with insect rearing is presented for lettuce cultivation. The nutrition cycle among crops, insects and fish turns waste into resource, thereby increasing the sustainability of this food production system. A comprehensive evaluation of the system’s efficiency was performed, including the growth, functional and resource use efficiency traits of lettuce, the dynamics of which were followed in a pilot-scale aquaponics greenhouse, under three treatments: conventional hydroponics (HP) as the control, coupled aquaponics (CAP) with crops irrigated with fish-derived water, and decoupled aquaponics (DCAP), where fish-derived water was amended with fertilizers to reach the HP target. The main findings indicate comparable physiological performance between DCAP and HP, despite the slightly lower yield observed in the former. The CAP treatment exhibited a significant decrease in biomass accumulation and functional impairments, which were attributed to reduced nutrient levels in lettuce leaves. The DCAP treatment exhibited a 180% increase in fertilizer use efficiency compared to the HP treatment. We conclude that the tri-trophic cropping system with the implementation of DCAP variant is an effective system that enables the combined production of crops and fish, the latter being fed with sustainably derived insect protein. The tri-trophic system improves the environmental impact and sustainability of lettuce production, while making circularity feasible. Full article

As potable water becomes limited, alternative water sources, such as reclaimed wastewater, for crop irrigation have gained attention. However, reclaimed wastewater for irrigation may expose edible crops to compounds of emerging concern (CECs), which may include pharmaceutics, hazardous waste, and volatile substances. Of these CECs, carbamazepine (CBZ) is of particular interest because only 7% of CBZ is filtered out during traditional wastewater treatment processing methods. Two trials were designed to evaluate the uptake and partitioning of CBZ in lettuce grown in a deep-water culture system (DWC) at low and high concentrations. The first trial (0 µg L⁻¹, 12.5 µg L⁻¹, 25 µg L⁻¹, and 50 µg L⁻¹) of CBZ had few effects on lettuce (Lactuca sativa var. capitata) growth, and low concentrations of accumulated CBZ were found in lettuce tissues. As a result, increased concentrations of CBZ were used in the second trial (0 mg L⁻¹, 21 mg L⁻¹, 41 mg L⁻¹, and 83 mg L⁻¹). Greater amounts of CBZ accumulated in plant tissues and the application of higher rates of CBZ negatively affected the growth and overall health of the lettuce. Further research is needed to determine the impacts of CECs on plant uptake and growth, as well as the environmental conditions. Full article

Vertical farming systems offer an efficient solution for sustainable food production in urban areas. However, managing nitrate (NO₃⁻) levels remains a significant challenge for improving crop yield, quality, and safety. This study evaluated the effects of nitrate availability on growth performance, nutrient uptake, and water use efficiency in a vertical hydroponic system that intercropped lettuce (Lactuca sativa) with alfalfa (Medicago sativa). The experiment was conducted in a controlled vertical hydroponic system using Nutrient Film Technique (NFT) channels, with nitrogen levels set at 0, 33, 66, 100, and 133% of the standard concentration. The results indicated that the intercropping treatment with 66% nitrate (IC-N_66%) improved water use efficiency by 38% and slightly increased leaf area compared to the other intercropping treatments. However, the control group, which consisted of a monoculture with full nitrate supply, achieved the highest overall biomass. Ion concentrations, including nitrate, calcium, magnesium, and micronutrients, were moderately affected by the intercropping strategy and nitrate levels. These findings suggest that moderate nitrate input, combined with nitrogen-fixing legumes, can enhance resource efficiency in hydroponic systems without significantly compromising yield. These findings offer a promising framework for incorporating legumes into hydroponic systems, minimizing the need for synthetic inputs while maintaining yield. These results support the use of agroecological intensification strategies in highly efficient soilless systems. Full article