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One of the major challenges that global society is facing nowadays is finding sustainable and safe methods for crop growth and development. Besides the traditional crops cultivated worldwide (tomatoes, potatoes, lettuce, strawberries, etc.), there is a general trend in the exploitation of polyvalent plants. Mulberry (Morus spp.) faced no exception; with its undeniable proprieties, it became suitable not only to be used in the sericulture industry, but in the food chain, the pharma industry, and environmental safety. Spare parts of the plants can be used in a very wide range, starting from introducing mulberry leaves in supplements to increase the protein content of a meal to extracting biologically active compounds from fruits and roots to be used in phytotherapy. However, the outstanding proprieties of this plant come with some requirements related to space availability and watering; requirements that can be easily surpassed by using vertical farming methods, such as hydroponic, aeroponic, or aquaponic systems. The present paper aims to evaluate vertical farming techniques' applicability to mulberry propagation in a controlled environment and their prospects for a more sustainable and safer agricultural practice. [ABSTRACT FROM AUTHOR]

Saltwater aquaponics is a sustainable alternative system for food production. The success of this system largely depends on the selection of both fish and plant species, for which several features and criteria must be considered. This paper aims to identify the most suitable plant species for saltwater aquaponics by using a multi-criteria decision-making method also based on current literature. One simple model that contained one root criterion, four aggregated criteria, and four sub-criteria was created using DEXi software. The same model was evaluated considering two different salinity levels in the recirculating water: 10 (brackish water) and 35 (sea water) g L−1. The relevance of the model structure was evaluated by the sensitivity analysis, through the 'plus/minus-1′ analysis. Our results suggest that Salicornia europaea L. and Portulaca oleracea L. were suitable species for saltwater aquaponics at 35 g L−1. Moreover, at 10 g L−1, the suitable candidates were: Salicornia bigelovii Torr, S. europaea L., Beta vulgaris ssp. maritima (L.) Arcang, Atriplex hortensis L., and P. oleracea L. The DEXi analysis resulted in being an easy and effective tool to select proper species in similar contexts. DEXi can help to identify the hotspots of production processes, according to our results. Since the selected species are wild edible species or minor crops, the availability of their seeds is one of the main constraints of their cultivation in saltwater aquaponics. [ABSTRACT FROM AUTHOR]

Zero-discharge and low-input aquaponics systems are a promising alternative to the intensive agricultural and aquacultural production systems currently used, ensuring high environmental sustainability. However, new approaches and management practices are needed to increase their productivity to reach the yields of classic production systems. In this context, the present study investigated for the first time the potential of two biostimulants to improve lettuce performance in aquaponics, whether coupled or decoupled, with hydroponics serving as a control. A comprehensive evaluation was conducted to assess the plant functional (focusing on the photosynthetic process evaluation) and growth responses at the whole-plant level. In addition, the nutritional state of the leaves was determined and metabolomic analysis was performed at the cellular level, the latter also for the first time in aquaponics research. The results demonstrated the limitations that coupled aquaponics poses in relation to lettuce growth, function and metabolism, which were already obvious from the 12th day of the experiment. Indicatively, the plants grown under coupled aquaponics exhibited a notable decrease in the leaf fresh weight, potassium content and nitrogen content, with reductions of 80%, 60%, and 30%, respectively, in comparison to the hydroponics control. However, the combined physiological and metabolomic data indicate that these plants down-regulate processes and metabolism to acclimate to low nutrient levels in lettuce leaves rather than experiencing damage. The application of biostimulants did not significantly optimize the plants' performance, though one of them appeared to be effective in improving some aspects of the photochemical efficiency. The decoupled and hydroponics systems resulted in similarly high yields and efficiency in terms of plant function, without any marked contribution from the biostimulants. We conclude that the decoupled aquaponics system has been successful in achieving yields comparable to those of hydroponics, with lower chemical inputs. Future studies should focus on examining other biostimulants in this system to further improve its performance while maintaining its environmental benefits within a circular economy framework. [ABSTRACT FROM AUTHOR]

Consumers are becoming increasingly concerned about eating healthy, and the products they consume are produced in an environmentally friendly way. Therefore, in this work, production techniques such as aquaculture and the use of plant growth-promoting bacteria in kohlrabi cultivation (Brassica oleracea L.) were studied. To this end, we applied three types of irrigation treatments (control, mixed water (50% fish effluent/50% drainage water) (mixed water), and mixed water enriched with synthetic fertilizers (mixed water + S)) combined with two formulations of plant growth-promoting bacteria (B1 and B2) in kohlrabi plants. Our data showed that the B1 inoculum combined with control irrigation caused both the increase in dry matter and the diameter of the bulb (17.8% and 8.9%, respectively); moreover, this inoculum increased the concentration of Ca when applied with mixed irrigation solution (water + S), and Zn for the B2 inoculum. The nitrogen utilization efficiency (NUtE) was augmented by the mixed irrigation treatment, with the lowest concentration of nitrates observed in the bulbs. Both inocula increased the total phenolic compounds in the control irrigation, whilst an increase in fructose and sucrose concentrations was only observed with B2. [ABSTRACT FROM AUTHOR]

Aquaponics is a promising cultivation technique for combined production of crops and fish, on the condition of tackling certain nutrients deficiencies. The aim of the present study was to examine the limitations imposed by the system on spinach (Spinacia oleracea) growth and functional performance and to identify the minimum nutrient supplementation for their optimization. Spinach was co-cultivated with red tilapia under three treatments; iron (Fe) and iron with potassium (Fe+K) enrichment was compared with the no-external input control. During a 45-day experiment, the photosynthetic performance, photosynthetic machinery efficiency, total chlorophylls content, and leaf reflectance were monitored, along with leaf nutritional state, antioxidant activity, and growth responses of fish and crops. Control plants showed symptoms of Fe deficiency, extensive chlorosis, stunted growth, and functional impairment already from day 10. The latter consisted of a coordinated down-regulation of photochemistry, carboxylation, and light-use efficiency. Fe-treated plants exhibited similar growth and functional performance with Fe+K-treated plants but outperformed them in chlorophyll content, photosynthetic rates, and photochemical efficiency, mainly due to higher quantum yield of electron transport. Fish growth remained unaffected. Fe-deficiency was identified as the major bottleneck for spinach cultivation in closed-loop aquaponics, and our results demonstrate that only Fe supplementation may sufficiently improve spinach function and yield. [ABSTRACT FROM AUTHOR]

One of the major challenges that global society is facing nowadays is finding sustainable and safe methods for crop growth and development. Besides the traditional crops cultivated worldwide (tomatoes, potatoes, lettuce, strawberries, etc.), there is a general trend in the exploitation of polyvalent plants. Mulberry (Morus spp.) faced no exception; with its undeniable proprieties, it became suitable not only to be used in the sericulture industry, but in the food chain, the pharma industry, and environmental safety. Spare parts of the plants can be used in a very wide range, starting from introducing mulberry leaves in supplements to increase the protein content of a meal to extracting biologically active compounds from fruits and roots to be used in phytotherapy. However, the outstanding proprieties of this plant come with some requirements related to space availability and watering; requirements that can be easily surpassed by using vertical farming methods, such as hydroponic, aeroponic, or aquaponic systems. The present paper aims to evaluate vertical farming techniques’ applicability to mulberry propagation in a controlled environment and their prospects for a more sustainable and safer agricultural practice.

Aquaponics is a human-made recirculating ecosystem that integrates the cultivation of crops and aquaculture to produce higher-quality, safe, and nutritious food. However, limited studies have been conducted to investigate the performance of different aquaponic plant growing systems. As such, the current research focuses on evaluating the overall performance of four different aquaponic growing systems in the growth and yield of lettuce and pak choi. The data on the shoot and root biomass and growth parameters were collected, and the growth analysis was performed. The relative growth rate results indicated that the appropriate environmental conditions were provided for lettuce and pak choi to grow successfully in all the four aquaponic growing systems. The crop growth rate results revealed that all four aquaponic growing systems tested in this experiment were able to grow crops and provide yield successfully. However, the substrate-based closed capillary water distribution system (CCWD) had the best overall result, which showed great potential for aquaponic applications to promote alternative agriculture production under unfavored climate conditions. [ABSTRACT FROM AUTHOR]

The primary objective of this research was to compare lettuce performance under conventional hydroponics at pH 5.8 (referred to as H5), hydroponics at pH 7.0 (referred to as H7), and recirculated aquaponic water at pH 7.0 (referred to as A7). Aquaponic nutrients were supplied by continuously recirculating water between a fish rearing system (recirculating aquaculture system or RAS) and the lettuce growing system (with the sole addition being chelated iron). This paper builds upon our previous research where we found that H7 produced 26% less shoot fresh weight (FW) growth than H5 and an 18% reduction in dry weight (DW). In this research, we also evaluated the inorganic hydroponics nutrient solution at pH 7.0 (H7) to provide continuity between experiments and to isolate the pH effect. The A7 plant biomass responses were not different from H5 in all biomass response categories. H7 was different from H5 in shoot FW, DW, and DW/FW, as well as root FW and DW. H7 was different from the A7 in shoot FW, DW/FW, and root DW. There were no tissue elemental differences between H5 and H7 except Cu. The Ca and Na contents differed between H5 and A7, while the microelements Mn, Mo, and Zn differed. Generally, the elemental tissue differences between treatments were proportional to the differences for the same elements in the nutrient solutions. Aquaponic systems are often viewed to be more complicated and more risky because two complex systems are being joined (hydroponics plus RAS). However, the aquaponics system proved to be surprisingly simple to manage in daily operations. Our data suggested that the aquaponics system (A7), which was operated at a higher pH 7.0, was able to offset any negative biomass and elemental effects that occurred in the inorganic hydroponic pH 7.0 treatment (H7) from its increased pH and less optimized nutrient solution elemental concentrations.

Fresh vegetables harbour diverse bacterial populations on their surfaces which are important for plant health and growth. Information on epiphytic bacteria is limited to only a few types of vegetables and it is unknown how the lettuce epiphytic bacterial community structure may respond when a probiotic product is added to an aquaponic system. In this study, we evaluated lettuce growth and analysed epiphytic bacterial communities of lettuce based on metabarcoding analysis of the V3-V4 region of the 16S rRNA gene obtained from paired-end Illumina MiSeq reads. The addition of Bacillus probiotics resulted in a significant increase of nitrate and phosphate in the deep-water culture solution, as well as increased vegetative growth of lettuce. Metabarcoding analysis revealed that the most abundant phyla on lettuce leaf surfaces were Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria. The in-depth bacterial composition analysis indicated that genera Chryseobacterium, Bacillus, Pantoea, Pseudoduganella, Flavobacterium, Paludibacter, and Cloacibacterium were dominant in leaf samples obtained from Bacillus-treated systems. Analysis of lettuce epiphytic bacterial communities of the fresh lettuce leaf surfaces also indicated the presence of food-borne pathogens belonging to the Shigella and Aeromonas genera, which were less abundant in the probiotic treated systems. This study provides the first characterization of the epiphytic bacterial community structure and how it can be modulated by the addition of a probiotic mixture to the nutrient solution of aquaponic systems. [ABSTRACT FROM AUTHOR]

Aquaponics combines raising fish and growing plants by recycling water and nutrients to reduce water consumption and reliance on chemical fertilizers. Coupled aquaponics systems recirculate water between fish and plant crops, whereas decoupled systems send mineralized fish effluent and wastewater unidirectionally to an independent hydroponic loop. Decoupling enables changes to the water, such as pH adjustments and complementary nutrient additions, to promote plant performance. In this study, basil, Ocimum basilicum (L.), was transplanted into 4 L containers filled with decoupled aquaponic (DAP), nutrient-complemented decoupled aquaponic (DAP+), or chemical-based conventional hydroponic (CON) nutrient solutions and grown for 21 days at pH 5.8. Plants grown in DAP+ and CON had greater biomass, height, and Soil Plant Analysis Development (SPAD) chlorophyll index and lower root:shoot biomass ratios than those in DAP. Shoot fresh and dry biomass was 11% greater for CON than DAP+, while height, SPAD chlorophyll index, and root:shoot ratio did not differ. We concluded that added nutrients in DAP+ enhanced performance compared to DAP, and the biologically derived nutrition in DAP+ enhanced performance to be similar, but not equal, to CON. We cannot recommend specific adjustments to the targeted blend of complementary nutrients tested, but findings suggest that complementary nutrients are effective in decoupled aquaponics. [ABSTRACT FROM AUTHOR]