Decreasing arable land, rising urbanization, water scarcity, and climate change exert pressure on agricultural producers. Moving from soil to soilless culture systems can improve water use ...efficiency, especially in closed-loop systems with a recirculating water/nutrient solution that recaptures the drain water for reuse. However, the question of alternative materials to peat and rockwool, as horticultural substrates, has become increasingly important, due to the despoiling of ecologically important peat bog areas and a pervasive waste problem. In this paper, we provide a comprehensive critical review of current developments in soilless culture, growing media, and future options of using different materials other than peat and rockwool. Apart from growing media properties and their performance from the point of view of plant production, economic and environmental factors are also important. Climate change, CO2 emissions, and other ecological issues will determine and drive the development of soilless culture systems and the choice of growing media in the near future. Bioresources, e.g., treated and untreated waste, as well as renewable raw materials, have great potential to be used as growing media constituents and stand-alone substrates. A waste management strategy aimed at reducing, reusing, and recycling should be further and stronger applied in soilless culture systems. We concluded that the growing media of the future must be available, affordable, and sustainable and meet both quality and environmental requirements from growers and society, respectively.
The soilless culture system is a promising, intensive, and sustainable approach with various advantages for plant production. The Special Issue “Soilless Culture, Growing Media, and Horticultural ...Plants” includes 22 original papers and 1 review written by 84 authors from 15 countries. The purpose of this Special Issue was to publish high-quality research articles that address the recent developments in the cultivation of horticultural plants in soilless culture systems and solid growing media. The published articles investigated new developments in simplified and advanced systems; the interaction between soilless and environmental factors with their effects on plant growth and photosynthesis, and the accumulation of secondary metabolites; the analyses of nutrient solution and hydraulic properties of substrates and mixtures; and the microbe–plant growing media interactions. Climate change and environmental and ecological issues will determine and drive the development of soilless culture systems and the choice of growing media constituents in the near future. Bioresources and renewable raw materials have great potential for use as growing medium constituents.
In soilless cultivation, plants are grown with nutrient solutions prepared with mineral nutrients. Beneficial microorganisms are very important in plant nutrition. However, they are not present in ...soilless culture systems. In this study we investigated the impact of introducing Plant Growth Promoting Rhizobacteria (PGPR) as an alternative to traditional mineral fertilizer in hydroponic floating lettuce cultivation. By reducing mineral fertilizers at various ratios (20%, 40%, 60%, and 80%), and replacing them with PGPR, we observed remarkable improvements in multiple growth parameters. Applying PGPR led to significant enhancements in plant weight, leaf number, leaf area, leaf dry matter, chlorophyll content, yield, and nutrient uptake in soilles grown lettuce. Combining 80% mineral fertilizers with PGPR demonstrated a lettuce yield that did not significantly differ from the control treatment with 100% mineral fertilizers. Moreover, PGPR application improved the essential mineral concentrations and enhanced human nutritional quality, including higher levels of phenols, flavonoids, vitamin C, and total soluble solids. PGPR has potential as a sustainable substitute for synthetic mineral fertilizers in hydroponic floating lettuce cultivation, leading to environmentally friendly and nutritionally enriched farming.
Salinity, a significant abiotic stressor, imperils vegetable growth, yield, and quality. Moreover, elevated salinity levels, driven by climate change, jeopardize vegetable nutritional quality. In ...particular, protected cultivation systems, responsible for 60% of the global vegetable industry's economic value, encounter notable challenges in managing salinity due to water runoff and drainage mechanism limitations. Therefore, it is crucial to understand the intricate mechanisms that control salinity and use this knowledge to improve plant tolerance to these conditions. In this study, we explore strategies to effectively mitigate the detrimental impacts of salinity on vegetable crops cultivated within protected environments. Additionally, we investigate the benefits of controlled moderate salinity adjustments in protected cultivation to enhance their nutritional content. Moderate salinity or nutrient solution increases typically raise total soluble solids, sugar, vitamin C, phenols, lycopene, and antioxidants in most fruit vegetables. Though generally applicable to leafy vegetables, exceptions like lettuce and wild rocket may show inconsistencies, potentially reducing some quality traits. Interdisciplinary approaches are essential to developing sustainable solutions for managing salinity in protected cultivation systems, thereby ensuring the resilience of vegetable production in the face of changing environmental conditions. Given the impracticality of desalinating all areas, future research should also investigate synergies between moderate salinity stress, cultivars used, and environmental factors from physiological and molecular perspectives to enhance vegetable nutritional quality.
Hydroponics is one of the systems in agriculture which reinforce productivity by controlling environmental and growing conditions. In this study, we evaluated the effect of three bio-fertilizers, ...namely bacteria, micro-algae, and mycorrhiza, on basil leaf yield and quality (Ocimum basilicum L.) in a floating culture system. Soil has rich amounts of beneficial microorganisms, supporting plant nutrition, producing phytohormones, controlling phytopathogens, and improving soil structure. However, soilless culture usually contains no beneficial microorganisms if we do not include them in the system. This study aims to evaluate the response of three bio-fertilizers where mineral fertilizers are reduced by 50%. Considering the total harvest data, bacteria, mycorrhiza, and micro-algae treatments increased basil yield compared to 50% control by about 18.94%, 13.94%, and 5.72%, respectively. The maximum total yield and leaf area were recorded using bacteria with 2744 g m
and 1528 cm
plant
. Plants with mycorrhiza achieved the highest number of leaves and branches, with 94.3 leaves plant
and 24.50 branches plant
, respectively. It was observed that this bio-fertilizer increased the formation of lateral branches in the basil plant without thickening its stems. In addition, bacteria and mycorrhiza induced the highest percentage of dry matter and total soluble solids. The effect of bio-fertilizers on basil leaf EC and pH was insignificant for all the treatments at different harvest periods (p < 0.05). Using bio-fertilizers enhanced the intake of nutrients N (nitrogen), P (phosphorus), K (potassium), Ca (calcium), Mg (magnesium), Fe (iron), Mn (manganese), Zn (zinc), and Cu (copper). Using bio-fertilizers represents a promising and environmentally friendly approach to increasing crop yields and ameliorating quality and antioxidant compounds with fewer resources. An application of bio-fertilizers in hydroponic cultivation of basil cv. 'Dino' reduced the need for mineral fertilizers. At the same time, bio-fertilizers affected an increased plant yield and improved product quality. Furthermore, the bacteria had a pronounced enhancing effect on the increase of phenol and flavonoids in the leaves of basil plants.
Abstract Backround The utilization of high-quality water in agriculture is increasingly constrained by climate change, affecting availability, quality, and distribution due to altered precipitation ...patterns, increased evaporation, extreme weather events, and rising salinity levels. Salinity significantly challenges salt-sensitive vegetables like lettuce, particularly in a greenhouse. Hydroponics water quality ensures nutrient solution stability, enhances nutrient uptake, prevents contamination, regulates pH and electrical conductivity, and maintains system components. This study aimed to mitigate salt-induced damage in lettuce grown via the floating culture method under 50 mM NaCl salinity by applying biostimulants. Results We examined lettuce’s physiological, biochemical, and agronomical responses to salt stress after applying biostimulants such as amino acids, arbuscular mycorrhizal fungi, plant growth-promoting rhizobacteria (PGPR), fulvic acid, and chitosan. The experiment was conducted in a greenhouse with a randomized complete block design, and each treatment was replicated four times. Biostimulant applications alleviated salt’s detrimental effects on plant weight, height, leaf number, and leaf area. Yield increases under 50 mM NaCl were 75%, 51%, 31%, 34%, and 33% using vermicompost, PGPR, fulvic acid, amino acid, and chitosan, respectively. Biostimulants improved stomatal conductance (58–189%), chlorophyll content (4–10%), nutrient uptake (15–109%), and water status (9–107%). They also reduced MDA content by 26–42%. PGPR (1.0 ml L ‒1 ), vermicompost (2 ml L ‒1 ), and fulvic acid (40 mg L ‒1 ) were particularly effective, enhancing growth, yield, phenol, and mineral content while reducing nitrate levels under saline conditions. Conclusions Biostimulants activated antioxidative defense systems, offering a sustainable, cost-effective solution for mitigating salt stress in hydroponic lettuce cultivation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Plant nutrition through mineral fertilizers is commonly used in soilless culture systems. Our study aims to replace intensive mineral fertilizers with bio-fertilizers, at least partially. We ...supplemented 50% of the mineral fertilizers with Chlorella vulgaris microalgae, a mix of beneficial bacteria and mycorrhiza. In addition, we investigated how to enhance spinach quality by implementing a sustainable and eco-friendly production method. Our research focused on analyzing the parameters of leaf quality and nitrate accumulation of baby spinach grown in a floating culture system utilizing biofertilizers. When mycorrhiza, algae, and bacteria supplemented 50% of mineral fertilizers, 17.5%, 20%, and 21.9% fewer leaf yields than 100% mineral fertilizers (5270 g m−2) were achieved. However, biofertilizers improved the internal leaves’ quality of hydroponically grown baby spinach. The highest amount of total phenolic (356.88 mg gallic acid 100g−1), vitamin C (73.83 mg 100 g−1), total soluble solids (9.4%), phosphorus (0.68%), and iron (120.07 ppm) content were obtained by using mycorrhiza. Bacteria induced the lowest nitrate content (206 mg kg−1) in spinach leaves, while 100% mineral fertilizers showed the highest nitrate (623 mg kg−1) concentration. Moreover, bacteria provided the highest SPAD-chlorophyll (73.72) and titrable acidity (0.31%). The use of microalgae, Chlorella vulgaris, induced the highest amount of potassium (9.62%), calcium (1.64%), magnesium (0.58%), zinc (75.21 ppm), and manganese (64.33 mg kg−1). In conclusion, our findings demonstrate that the utilization of biofertilizers has the potential to significantly reduce the reliance on mineral fertilizers by up to 50%. Furthermore, an improvement in the quality of baby spinach, as evidenced by an increase in health-beneficial compounds, is possible. Thus, implementing biofertilizers in the cultivation of soilless baby spinach presents a promising approach to achieving both environmental sustainability and improved crop quality.
During the seasons with limited light intensity, reductions in growth, yield, and quality are challenging for commercial cut rose production in greenhouses. Using artificial supplemental light is ...recommended for maintaining commercial production in regions with limited light intensity. Nowadays, replacing traditional lighting sources with LEDs attracted lots of attention. Since red (R) and blue (B) light spectra present the important wavelengths for photosynthesis and growth, in the present study, different ratios of supplemental R and B lights, including 90% R: B 10% (R90B10), 80% R: 20% B (R80B20), 70% R: 30% B (R70B30) with an intensity of 150 µmol m
s
together with natural light and without supplemental light (control) were applied on two commercial rose cultivars. According to the obtained results, supplemental light improved growth, carbohydrate levels, photosynthesis capacity, and yield compared to the control. R90B10 in both cultivars reduced the time required for flowering compared to the control treatment. R90B10 and R80B20 obtained the highest number of harvested flower stems in both cultivars. Chlorophyll and carotenoid levels were the highest under control. They had a higher ratio of B light, while carbohydrate and anthocyanin contents increased by having a high ratio of R light in the supplemental light. Analysis of chlorophyll fluorescence was indicative of better photosynthetic performance under a high ratio of R light in the supplemental light. In conclusion, the R90B10 light regime is recommended as a suitable supplemental light recipe to improve growth and photosynthesis, accelerate flowering, and improve the yield and quality of cut roses.
This study investigated the effects of vermicompost fertilization with complementary microbial nutrition on the plant growth, yield, and fruit quality of the organically grown strawberry “Monterey” ...cultivar. Along with vermicompost, five different microbial fertilizers containing plant-growth-promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) were used as complementary nutrition. Here, we examined plant growth parameters, strawberry yield, fruit weight, pH, total soluble solids, and acidity in fruit and leaf mineral nutrient concentrations. Vermicompost-based fertilization with PGPR and AMF improved plant growth, yield, and fruit quality. The highest total yield (216.75 g per plant−1) and heaviest fruits with an average of 18.11 g were obtained from the vermicompost-based fertilization with PGPR containing complementary fertilization. This included Bacillus amyloliquefaciens, Bacillus pumilus, Bacillus subtilis, Bacillus licheniformis, Bacillus megaterium, Trichoderma harzianum, and Trichoderma konigii. This treatment also resulted in the best ratio of total soluble solids to acidity (18.74), pH (3.95), and mineral nutrient concentrations in leaves. The novel approach with vermicompost-based fertilization and complementary microbial nutrition improves organic strawberries’ growth, yield, and fruit quality. These results are promising for enhancing organic strawberry production.
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