Search Results (84)

Growing pressure on water resources and mineral fertilizer use calls for innovative and resource-efficient agri-food systems. Aquaponics, integrating aquaculture and hydroponics, represents a promising approach for sustainable greenhouse production. This study, aiming to explore alternative water and nutrient sources for greenhouse tomato production without compromising plant adaptability or yield, evaluated the co-cultivation of grape tomato and rainbow trout in a vertical decoupled aquaponic system under controlled greenhouse conditions. Two aquaponic nutrient strategies were tested: unmodified aquaponic water (AP) and complemented aquaponic water (CAP), with conventional hydroponics (HP) as a control, in a Deep Water Culture hydroponic system. Plant performance was assessed through marketable yield and physiological parameters, while system performance was evaluated using combined-biomass Energy Use Efficiency (EUE), Freshwater Use Efficiency (fWUE) and Nitrogen Use Efficiency (NUE), accounting for both plant and fish production. CAP significantly improved tomato yield (9.86 kg m⁻²) compared to AP (2.40 kg m⁻²), although it remained lower than HP (12.14 kg m⁻²). Fresh WUE was comparable between CAP and HP (9.22 vs. 9.24 g L⁻¹), demonstrating effective water reuse. In contrast, EUE and NUE were lower in CAP, reflecting the additional energy demand of the recirculating aquaculture system and nutrient limitations of fish wastewater. These results highlight aquaponics as a water-efficient production system while emphasizing that optimized nutrient management and energy strategies are critical for improving its overall sustainability and performance. Full article

Urban densification threatens biodiversity, yet conventional greenspace expansion is constrained by limited land availability. Living wall systems (LWS) offer potential biodiversity enhancement through vertical green infrastructure, though their ecological value remains underexplored. This study evaluated the biodiversity performance of three LWS in Plymouth, UK, using multi-taxa surveys to assess invertebrate communities, bird assemblages, and bat activity. A scoping review of 2638 publications revealed limited research on LWS biodiversity, with only 27% of biodiversity-focused papers referencing specific species. Field surveys employed standardised protocols including flower-visiting pollinator observations, spider assessments, soil invertebrate extraction using Tullgren funnels, acoustic bird monitoring, and bat emergence surveys across soil-based and hydroponic systems. Results demonstrated that soil-based LWS supported significantly higher invertebrate diversity than hydroponic systems, with 481 soil invertebrates recorded across 19 families. Plant species composition strongly influenced biodiversity outcomes, with Hedera helix, Erigeron karvinskianus, and Lonicera japonica attracting the most pollinator species (5 each). Bird abundance was significantly higher at LWS sites compared to control areas, with confirmed breeding by three species. However, current UK Biodiversity Net Gain frameworks undervalue LWS contributions due to their classification as artificial habitats. These findings indicate that appropriately designed soil-based LWS can deliver meaningful urban biodiversity benefits when integrated with strategic plant selection and species-based valuation approaches. Full article

Climate change or even the natural occurrence of periods of low suitability for the production of forage species are obstacles to maintaining adequate animal nutrition. Indoor green fodder production is an alternative to this problem; however, advances in technologies capable of improving this system still need to be studied in depth. The objective of this study was to evaluate the qualitative and quantitative characteristics of hydroponic green fodder production of millet and sorghum under varying monochromatic light supplementation and nicotinamide application. Eight treatments were defined by lighting (LS—Led Full Spectrum; LS + Ultraviolet LED; LS + Red LED; LS + Blue LED), and combined with the application of nicotinamide (with and without) at a concentration of 200 mg L⁻¹. Cultivation under conditions of light supplementation with UV radiation or monochromatic lights results in increased light intensity by modifying the wavelength spectrum received by the plant, modification of the quality of photons received in relation to the energy level that leads to luminous stress and, consequently, lower green fodder development concerning height and fresh mass. Nicotinamide acts as a bioprotectant, attenuating the stressful effects and enabling greater productive efficiency in the production of hydroponic green fodder, particularly in vertical cultivation, which provides increased height and fresh mass for millet and sorghum green fodder. In contrast, the stress resulting from light supplementation can be used as a tool to increase carotenoid levels in plants and may be indicated for production systems that have this objective for biofortification of forages with bioactives with antioxidant effects. Full article

Food security and supply networks are becoming an ever-increasing concern requiring innovative practices to deal with the contributing factors. Controlled Environment Agriculture (CEA) offers an alternative to conventional cropping systems for increasing the yields of certain produce types. Crop yields (tons/hectare/year) in CEA are reported to range between 10 and 100 times higher than open-field agriculture, and the water use in CEA is typically about 4.5–16% of that from conventional farms per unit mass of produce. However, these systems can be energy intensive due to temperature regulation requirements, compromising their environmental and economic viability. Energy is the second largest overhead cost in CEA with carbon footprints being reported as 5.6–16.7 times and 2.3–3.3 times greater than that of open-field agriculture for indoor vertical farms and greenhouses, respectively. This can be offset, in part, by reducing the reliance on cooling systems. However, high temperature stress negatively impacts crops at morphological, cellular, metabolic, and molecular levels, reducing produce quality and quantity. Biostimulants are additives which can benefit plant growth through ameliorating stress. This review considers recent research on the effects of heat stress on a variety of crops commonly grown in CEA and the categories of biostimulants that have known thermoprotective qualities. Seaweed extracts, chitin/chitosan, protein hydrolysates and amino acids, inorganic compounds, beneficial microorganisms, and humic substances are explored, alongside the known benefits, limitations, and knowledge gaps. Full article

Resource efficiency is essential in today’s approach to horticulture. The global problems of water scarcity, soil pollution, biodiversity loss, and rapid growth of the global population require increased food production with fewer resources. Resource efficiency is an indicator that allows defining how much biomass an agri-food system can produce per unit of the resource used. Closed hydroponic systems, such as vertical hydroponic towers (VHTs), exhibit high resource efficiency. In these systems, the water use efficiency (WUE) and the nutrient use efficiency (NUE) can be calculated in terms of the water loss through transpiration and the ion concentration in the nutrient solution. The research aimed to determine the WUE and NUE for chard crops in VHT under greenhouse conditions and to evaluate its feasibility as an urban and peri-urban system for leafy vegetable production. Trials were carried out with chard in the fall 2024 in a tunnel-type greenhouse at the facilities of the Autonomous University of San Luis Potosi. The VHTs were built with a 20 L square lower deposit on which a cylindrical pipeline of 11.5 cm in diameter and 1.6 m in height was vertically placed. Each pipe had 45 growing containers distributed on 15 levels of three containers spaced vertically 9 cm and a density of 25 plants·m⁻². The experimental design was completely randomized with three treatments (75, 100, and 125% of Steiner’s nutrient solution) and three replications. The transpiration (Tr) of the crop (recording weight loss in the deposit) and the shoot fresh weight (SFW) of the plants were measured daily using a scale. An ANOVA and Tukey’s test for mean differentiation were performed with p < 0.05. Significant differences were found between treatments for SFW, WUE and NUE obtaining the best results at 75% of Steiner’s nutrient solution. Results show that WUE increased between 3 and 6 times, and NUE between 3 and 12 times compared to chard grown in soil. These results were equal and even higher than horizontal hydroponic systems or vertical farms. Vertical hydroponic closed towers installed in greenhouses are an optimal horticultural production system with high resources use efficiency. The implementation of VHT is feasible in areas where there is water scarcity or have a high population density. Full article

Indoor horticulture requires a substantial quantity of electricity to meet crops extended photoperiodic requirements for optimal photosynthetic rate. Simultaneously, global electricity costs have grown dramatically in recent years, endangering the sustainability and profitability of indoor vertical farms and/or modern greenhouses that use artificial lighting systems to accelerate crop development and growth. This study investigates the growth rate and physiological development of cherry tomato plants cultivated in a pilot indoor vertical farm at the Agricultural University of Athens’ Laboratory of Farm Structures (AUA) under continuous and disruptive lighting. The leaf physiological traits from multiple photoperiodic stress treatments were analyzed and utilized to estimate the plant’s tolerance rate under varied illumination conditions. Four different photoperiodic treatments were examined and compared, firstly plants grew under 14 h of continuous light (C-14L10D/control), secondly plants grew under a normalized photoperiod of 14 h with intermittent light intervals of 10 min of light followed by 50 min of dark (NI-14L10D/stress), the third treatment where plants grew under 14 h of a load-shifted energy demand response intermittent lighting schedule (LSI-14L10D/stress) and finally plants grew under 13 h photoperiod following of a load-shifted energy demand response intermittent lighting schedule (LSI-13L11D/stress). Plants were subjected also under two different light spectra for all the treatments, specifically WHITE and Blue/Red/Far-red light composition. The aim was to develop flexible, energy-efficient lighting protocols that maintain crop productivity while reducing electricity consumption in indoor settings. Results indicated that short periods of disruptive light did not negatively impact physiological responses, and plants exhibited tolerance to abiotic stress induced by intermittent lighting. Post-harvest data indicated that intermittent lighting regimes maintained or enhanced growth compared to continuous lighting, with spectral composition further influencing productivity. Plants under LSI-14L10D and B/R/FR spectra produced up to 93 g fresh fruit per plant and 30.4 g dry mass, while consuming up to 16 kWh less energy than continuous lighting—highlighting the potential of flexible lighting strategies for improved energy-use efficiency. Full article

Domestic wastewater discharge is the major source of pollution in Malaysia. Phytoremediation under hydroponic conditions was initiated to treat domestic wastewater and, at the same time, to resolve the space limitation issue by installing a hydroponic system in vertical space at the site. Water hyacinth (WH) was selected in this study to identify its performance of water hyacinth in removing nutrients in raw sewage under batch operation. In the batch experiment, the ratio of COD_initial/plant_initial was identified, and SPSS ANOVA analysis shows that the number of plant size factors was not statistically different in this study. Therefore, four WH, each with an initial weight of 60 ± 20 g, were recommended for this study. Throughout the 10 days of the batch experiment, the average of COD, BOD, TSS, TP, NH4, and color removal was 73%, 73%, 86%, 79%, 77%, and 54%, respectively. The WH biomass weight increased by an average of 78%. The plants have also improved the DO level from 0.24 mg/L to 4.88 mg/L. However, the pH of effluent decreased from pH 7.05 to pH 4.88 below the sewage Standard B discharge limit of pH 9–pH 5.50. Four WH plant groups were recommended for future study, as the COD removal among the other plant groups is not a statistically significant difference (p < 0.05). Furthermore, the lower plant biomass is preferable for the high pollutant removal performance due to the fact that it can reduce the maintenance and operating costs. 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

Plant-associated microbiomes play a critical role in plant health, nutrition, growth, and adaptation. This study aimed to investigate the formation pathways of the endospheric microbiome in lettuce (Lactuca sativa) through vertical (seed) and horizontal (substrate) transmission in hydroponic and soil environments. The bacterial microbiomes from the seeds, roots, leaves, and substrates were analyzed via 16S rRNA gene sequencing. The seed microbiome contained 236 OTUs dominated by Verrucomicrobia (31%) and Firmicutes (29%). Rhizospheric soil contained 1594 OTUs, while the hydroponic solution had 448 OTUs. The root endosphere from soil-grown lettuce contained 295 OTUs, compared with 177 in hydroponic conditions, and the leaf microbiome contained 43 OTUs in soil and 115 OTUs in hydroponics. In total, 30–51% of the leaf and root microbiomes originated from the seed microbiota, while 53–65% of the root microbiome originated from the substrate. Microbiome overlap was observed between the rhizospheric soil and the root microbiome. This study provides new insights into the microbiome of lettuce seeds and the pathways of formation of the endospheric microbiome in adult plants. These findings lay the groundwork for future research aimed at better understanding microbiome dynamics in leafy crops and plant protection. Full article

As climate change destabilizes food crop production, there is a growing interest in controlled environment agriculture (CEA). Although light-emitting diodes (LED) have made CEA economically viable for some high-value crops when coupled to agrivoltaics (solar photovoltaics + agriculture), it has generally not been used for root vegetables. This is the first study to demonstrate that radishes and turnips could be grown in a reasonable period of eight weeks in an agrivoltaic agrotunnel using both lighting and grow walls optimized for lettuce growth. As reduction in LED energy use is important to minimize capital costs for solar energy, this study investigated three lighting treatments (red, white, and full-spectrum as control). The normalized yields (adjusted for total energy provided by each treatment) showed that both cultivars preferred red light, and harvested green leaves provided higher masses than the roots, although turnips appeared to be far more adaptable to vertical growth than radishes (>450% for roots and >50% for leaves per pot compared to radishes for the control treatment). The results show promise for providing true net-zero carbon emission root vegetables year-round with similar agrivoltaics-powered CEAs. Future work is needed with light intensity trials to optimize light recipes. Full article

Rapid urbanization, climate variability, and land degradation are increasingly challenging traditional open-field farming systems. Soilless farming (SLF) has emerged as a complementary approach to enhance horticultural resilience in space-constrained and climate-stressed environments. This review critically evaluates the role of SLF within the broader framework of climate-smart agriculture (C-SA), with a particular focus on its applications in urban and peri-urban settings. Drawing on a systematic review of the existing literature, the study explores how SLF technologies contribute to efficient resource use, localized food production, and environmental sustainability. By decoupling crop cultivation from soil, SLF enables precise control over nutrient delivery and water use in enclosed environments, such as vertical farms, greenhouses, and container-based units. These systems offer notable advantages regarding water conservation, increased yield per unit area, and adaptability to non-arable or degraded land, making them particularly relevant for high-density cities, arid zones, and climate-sensitive regions. SLF systems are categorized into substrate-based (e.g., coco peat and rock wool) and water-based systems (e.g., hydroponics, aquaponics, and aeroponics), each with distinct design requirements, nutrient management strategies, and crop compatibility. Emerging technologies—including artificial intelligence, the Internet of Things, and automation—further enhance SLF system efficiency through real-time data monitoring and precision control. Despite these advancements, challenges remain. High setup costs, energy demands, and the need for technical expertise continue to limit large-scale adoption. While SLF is not a replacement for traditional agriculture, it offers a strategic supplement to bolster localized food systems and address climate-related risks in horticultural production. Urban horticulture is no longer a peripheral activity; it is becoming an integral element of sustainable urban development. SLF should be embedded within broader resilience strategies, tailored to specific socioeconomic and environmental contexts. Full article

This study explores the relationship between nutrient concentration (NC) and epidermal thickness (d) of the leaves of hydroponically grown Brassica rapa and its attenuation coefficients (m) using portable Time-Domain Optical Coherence Tomography (TD-OCT), which is a non-invasive imaging technique that uses low-coherence interferometry to generate axial scans of plants’ leaves by measuring the time delay and intensity of backscattered light. The portable TD-OCT system in this study has an axial and lateral resolution of 7 m and 3 m, respectively, a scanning depth of 12 mm, and a 1310 nm Super Luminescent Diode (SLD). Several studies suggest that the differences in d and m are related to nutritional, physiological, and anatomical status. The study used the Kratky method, a simple non-circulating hydroponic system, to cultivate Brassica rapa with varying NC (25%, 50%, 75%, 100% (control), and 125%). Each treatment group used two plants. The TD-OCT sample probe was placed on a fixed holder and was oriented vertically so that light was directed downward onto the leaf’s surface to obtain the depth profile (A-scan). The distance between the probe and the leaf was adjusted to obtain the optimum interference signal. Five averaged A-scans were obtained per leaf on the 7th, 18th, and 21st days post nutrient exposure. The logarithm of the averaged A-scan is linearly fitted to extract m. The results showed a positive correlation between NC and m, which suggests that plants produce more chlorophyll and develop denser cells and increase m. There was no correlation obtained between NC and d. The study demonstrates the potential of TD-OCT as a non-destructive tool for assessing plant health and monitoring growth dynamics in hydroponic systems and m as a sensitive indicator of plant health as compared to d. The continued exploration of TD-OCT applications in agriculture can contribute to improving crop management strategies and promoting sustainable food production practices. Full article

Light and nutrient availability are critical factors of plant growth and development, particularly at the early stages, where they significantly influence the establishment and survival of young seedlings. The morphological parameters and the biomass accumulation of soybean were measured in a hydroponic vertical farm in the first 14 days of seedling growth in two successive experiments under two types of lighting environments and at three nutrient concentration levels. The lighting conditions were set by two parallel variable-spectrum linear luminaires positioned above the lower and upper edges of the cultivation trays. In the first lighting environment, seedlings were exposed to a constant photosynthetic photon flux density (PPFD) with red and blue photon irradiance ratio (R/B) varying in broad range from the lower to the upper end of the cultivation trays. In the second environment, the spatial R/B distribution was uniform, and the PPFD varied between two maxima at the edges and a minimum in the middle of the trays. The R/B ratio within the 0.6–6 interval had little or no effect on plant development. We report the dependence of growth traits as a function of PPFD in the range of 30–290 µmol m⁻² s⁻¹ in full-strength, half-strength, and blank nutrient solutions. The light response for shoot height and the first internode length was mainly influenced by blue light. We observed a rapid decline in growth between 6–20 µmol m⁻² s⁻¹ blue photon irradiance. The shoot height and first internode length did not change significantly at higher blue light intensities. The lengths of the first internode and the root dry mass did depend on the nutrient solution strength. All other growth traits, including stem diameter, leaf size, shoot mass, root mass, and SPAD readings, showed a linear correlation with PPFD and electrical conductivity. The leaf mass and root mass ratios indicated that soybeans adopt a nutrient search strategy by giving preference for root growth while increasing shoot height at the expense of the shoot diameter in conditions of low nutrient availability and low light intensity. The functional relationships determined in the experiments provide valuable inputs to plant growth models. The methodology we employed could also be used to study other plant species and to investigate the interactive effects of specific nutrients and lighting conditions. Full article

The global food production sector is under immense pressure due to rapid population growth and climate change, demanding innovative solutions for food security and sustainability. This review explores innovative advancements in agriculture and food technology, from urban farming (e.g., vertical farming, aquaponics, and hydroponics) to regenerative agriculture and agroforestry practices that enhance soil health and biodiversity. We also examine food production in extreme environments, including desert agriculture and space agriculture, as well as advances in biotechnology, synthetic biology, and nanotechnology, that enable improved crop yields and nutrition. The transformative role of AI in precision farming, predictive analytics, and water management is highlighted, as well as the importance of bioproducts and eco-friendly innovations. Finally, we discuss the vital role of policy, regulation, and community-driven approaches in shaping a resilient global food system. Through the integration of technology with sustainable practices, this review aims to inspire research into solutions that ensure future food security while preserving our planet. Full article

This systematic review explores the use of digital twins (DT) for sustainable agricultural water management. DTs simulate real-time agricultural environments, enabling precise resource allocation, predictive maintenance, and scenario planning. AI enhances DT performance through machine learning (ML) and data-driven insights, optimizing water usage. In this study, from an initial pool of 48 papers retrieved from well-known databases such as Scopus and Web of Science, etc., a rigorous eligibility criterion was applied, narrowing the focus to 11 pertinent studies. This review highlights major disciplines where DT technology is being applied: hydroponics, aquaponics, vertical farming, and irrigation. Additionally, the literature identifies two key sub-applications within these disciplines: the simulation and prediction of water quality and soil water. This review also explores the types and maturity levels of DT technology and key concepts within these applications. Based on their current implementation, DTs in agriculture can be categorized into two functional types: monitoring DTs, which emphasize real-time response and environmental control, and predictive DTs, which enable proactive irrigation management through environmental forecasting. AI techniques used within the DT framework were also identified based on their applications. These findings underscore the transformative role that DT technology can play in enhancing efficiency and sustainability in agricultural water management. Despite technological advancements, challenges remain, including data integration, scalability, and cost barriers. Further studies should be conducted to explore these issues within practical farming environments. Full article