Maximizing Growth Rates of Various Lettuce Cultivars in an Aquaponics System By Alexia Bertholon, Shae-Lynn Roberts, and Ananka Shah Introduction (original) (raw)
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Aquaponics vs. Hydroponics: Production and Quality of Lettuce Crop
Acta Horticulturae, 2012
Aquaponics is a vegetable production system that integrates soilless cultivation and aquaculture. Plants strip nutrients from fish waste water and convert metabolites toxic to fish. Aquaponics is an environmental-friendly production system due to its full reuse of waste and nutrients. The research, carried out at the Experimental Farm of the University of Tuscia, compared summer yields of two romaine lettuce crops (Lactuca sativa L. 'Integral') grown on aquaponic and hydroponic floating systems. For the hydroponic treatment a nutritive solution of 1.7 dS m-1 and pH 5.5 supported plant growth. For the aquaponic system two treatments under different fish densities supplied nutrients at different concentrations. Every aquaponic treatment consisted of 3 independent 250-L tanks stocked with Nile tilapia (Oreochromis niloticus L.). Each fish tank fed a 1.5 m 2 floating system under a 20 plant m-2 density. For the first crop 110 g and 24 g tilapia were stocked at system setup respectively under a low (5 kg m-3) and high (8 kg m-3) density and supplied nutrients with an electrical conductivity (EC) of 0.4 and 0.6 dS m-1. For the second crop 168 g and 90 g tilapia respectively stocked under a low (6 kg m-3) and high (20 kg m-3) stocking density raised EC levels to 0.5 and 1.0 dS m-1. Production of 2.8 kg m-2 from the first hydroponic crop was similar to the 2.7 kg m-2 assessed in the high density aquaponic treatment. Conversely the 2.3 kg m-2 measured in the low density treatment was smaller. For the second trial no differences were noticed between the 6.0 kg m-2 measured in the hydroponic system and the 5.7 and 5.6 kg m-2 assessed in the high and low-density aquaponic treatments, respectively. Nevertheless different nutrient concentrations in water affected plant mineral composition. Aquaponic leaves were poorer in phosphorus but richer in calcium, potassium magnesium and sodium.
Lettuce production in aquaponic and hydroponic systems
Acta Universitatis Sapientiae, Agriculture and Environment, 2019
Besides soil cultivation, there are other alternative methods such as the aquaponic and the hydroponic technology. In our research, four lettuce varieties (‘Edina’, ‘Május királya’, ‘Lollo Rossa’, and ‘Lollo Bionda’) were compared by the use of different systems. In hydroponics, the direct nutrient supply resulted higher leaf weight. In addition, multiple values of nitrate (269.50–406.50 mg kg-1) were measured in this system compared to the aquaponic system (23.25–170.00 mg kg-1). The ‘Lollo Rossa’ stood out with higher element content (Zn, B, and Mg) in both cultivation methods. In conclusion, it can be stated that higher nutrient content in hydroponics resulted higher leaf weight, but nitrate values were also higher in this unit. Aquaponic technology can be used to produce high-quality (low-nitrate) lettuce with the ‘Lollo Rossa’ and ‘Lollo Bionda’ varieties.
vegetable production aquaponics
Background: In an integrated aquaponic system, the ratio between nitrogen production and plant assimilation is a key factor for system efficiency. That is why plant density is very important to be appropriate. Aims: The aim of this study is to expose the performances of growth parameters, both in terms of quantity and quality, for Nores variety spinach (Spinacia oleracea) produced in an aquaponic integrated system along with rainbow trout (Oncorhynchus mykiss), under three plant densities (V1 -59 plants/m 2 , V2 -48plants/m 2 and V3 -39plants/m 2 ). Materials and methods: The experimental design consist in a recirculating aquaculture system with 12 growing units, mechanical and biological water treatment units and four aquaponic units. Three plants densities were used (59, 48 and 39plants/m 2 ). A fish stocking density of 136fish/m 3 was used. Plants initial and final biomass was taken and a series of periodic measurements were made. Chlorophyll a, b and carotenoids, ash and dry matter were determined from spinach leaf. Results: The plant biomass gain registered good values and the quality of final plant products, given by the chlorophyll a, b, carotenoids and dry matter content were in the optimal variation interval, comparing to market spinach. Significant differences (p<0.05) between variants were observed.
2018
This experiment was carried out in a greenhouse at the Faculty of Agronomy, Hue University, Viet Nam. The objective of this research was to investigate the effects of the EC concentration levels on growth, yield and quality of lettuce under vertical hydroponic system. The experiment was laid out in Randomized Complete Block Design (RCBD) with four replications. Five treatments consist of the EC levels (0.5, 1.0, 1.5, 2.0 and 2.5 mS/cm). The Rapid Red lettuce cultivars was used for testing. Two weeks after germination, the seedlings were transplanted under the vertical hydroponic systems. The pH was maintained at 6.0 6.5 for the entire the growing period. It can be concluded that the ability to grow, yield and quality of lettuce grown in vertical hydroponic systems were significantly affected by nutrient solution concentrations (EC). Yield was significantly (P≤0.01) affected by EC levels. The EC at 2.5 mS/cm produced maximum yield (27.5 t/ha), but not significant difference with 2.0 ...
Journal of Agriculture and Aquaculture Research Article
Water is essential to all forms of life, including plants. It plays a crucial role in biological systems. In regions where water is scarce, farmers often have to use saline water in agriculture, due to a lack of good-quality water. Electromagnetic water treatment has been a controversial process for many years. However, in recent years, there has been an increase in commercial electromagnetic water treatment devices that many farmers trust in the agricultural sector. In a plastic greenhouse a few years ago, we used a low-cost device called "AQUASOFT" to create a high-frequency electromagnetic field for the nutrient solution of tomato plants growing in a closed hydroponic system. We found that exposing the nutrient solution, which contained a high amount of NaCl (total conductivity 13 dS m-1), to a high-frequency electromagnetic field just before it reached the plant roots, alleviated salinity stress. When we compared the application of the high-frequency electromagnetic field to the saline nutrient solution, we found that it greatly reduced the concentration of Na+ in the plant leaves, compared to the saline nutrient solution without the effect of the high-frequency electromagnetic field. The height of the plants was the same as those grown in a non-saline nutrient solution. Furthermore, their production was superior to that of the plants growing in a saline nutrient solution without the application of a high-frequency electromagnetic field. The effect of a high-frequency electromagnetic field on the saline nutrient solution was interpreted based on the increase of free water molecules coming from the surface of the hydrated ions and the contribution of the temporary neutralization of several ions due to collisions, originating from the high-frequency electromagnetic field.
Yield of lettuce grown in aquaponic system using different substrates
Revista Brasileira de Engenharia Agrícola e Ambiental
In the aquaponic system, the characteristics of the materials used as substrate directly affect plant development, because besides acting as a support base, they must present a surface to fix microorganisms, responsible for the conversion of nutrients into forms more easily available to plants. Thus, the objective of this study was to evaluate the effect of four growing substrates on the yield of lettuce grown in aquaponic system. The experimental design was randomized blocks with four treatments, which corresponded to the substrates, and six replicates. Plants were grown using the nutrient film technique (NFT) system. The substrates used in the experiment were: coconut shell fiber with crushed stone #3, expanded vermiculite, zeolite and phenolic foam. The treatment with phenolic foam was considered as the least suitable for lettuce cultivation in aquaponic system, because it caused lower yield (20.8 t ha-1). The treatment using coconut shell fiber with crushed stone #3 was consider...
Yield of two cultivars of lettuce (Lactuca sativaL.) in hydroponic and aquaponic systems
Acta Horticulturae, 2018
This research was carried out in order to evaluate the performance of two cultivars of lettuce (Lactuca sativa L.) in an aquaponic system in comparison with a hydroponic system. The studied factor was the dose of food supplied with a commercial diet for tilapia (Oreochromis sp.); the treatments were 80, 100 and 120% of the recommended diet, and, as a control, the hydroponic Steiner universal nutrient solution, arranged in an experimental design of randomized complete blocks with four replications. The variables measured were related to vegetative development (plant height, stem diameter, diameter of foliage, fresh weight and dry matter) and nutrient contents of plant tissue (N, P, K, Ca, Mg, Fe, Cu, Zn and Mn) as well as nutrient concentrations (N-NH 4 + , N-NO 3-, P-H 2 PO 4-, P-HPO 4 2-, K + , Ca 2+ , Mg 2+ , SO 4 2-, Fe 2+ , Mn 2+ , Zn 2+ , Cu 2+ and H 3 BO 3) in aquaponic nutrient solution during two crop cycles. Rocky mountain tilapia with a density of 20-25 kg m-3 in tanks and 25 lettuce plants m-2 on beds were used. It was found that treatment with 120% of the recommended fish diet produced the best fresh weight of lettuce, above hydroponic control; in the analysis of plant tissue, no nutrient deficiencies were observed. Nutrients in the aquaponic nutrient solution were within the ranges reported as adequate for optimal crop development. Supplying 80 or 120% of the recommended tilapia diet decreased by 21% or increased by 10%, respectively, tilapia weight in relation to the normal diet. The level of food supply influenced the length and weight of tilapia, the concentration of nutrients in the water and in the tissue of lettuce; aquaponics equalled or exceeded hydroponics in nutrient capacity supply for 'Andrómeda' and 'Ruby Sky' lettuce.
A System Study on La Estrella Aquaponics
2016
The system study focused on La Estrella Farms, which is one of the few known commercial practitioners of Aquaponics in the Philippines. The scope of the study looks into the performance of the company and their activities or processes, these being production, maintenance, purchasing, and the selling of products. After proper documentation and evaluation of the company’s practices and within the context of the stated objectives that is concerned with the production of the company, it was identified that the most prevalent problem that is being experienced by the company is their lack of productivity in the utilization of their current system. This led to the group’s problem statement of: “The weekly produce deviates by 74 kilos (75.51%) for lettuce and 24 (24.49%) for kale from the weekly target of 120 kilos for lettuce and 40 for kale. The Design of Experiments (DOE) tool was used for the analysis of the data gathered for analysis. The analysis of the experiment in Chapter 9 and 10 led to the findings that the deviation from the target production was caused by the underutilization of the tanks and the presence of algae in the system. Alternative set ups for the system were generated in order to address the production’s deviation and various proposed systems were created for the company to select from. The corresponding profitability analyses were computed with regards to the multiple alternative set ups and their resulting yields. To address the underutilization of tanks, the group proposes a fixed level of 75% tank utilization, taking into account approximately 25,000 fishes per tank in order to provide the nutrients needed for the production of lettuce and kale. In order to tackle the issue of algae presence within the Aquaponics system, the group concluded that a change in the media grow beds will minimize the said algae, and benefit the company through reducing costs from the purchasing of fast moving materials by an estimate 25% for expenses. The company has yet to review upon which of the said generated alternative set ups for the system was to be fully implemented to address the problem of the system’s production deviation. The alternative set ups consist of 8 combinations, making use of 25 and 75% tank utilization, systems that contain algae or those that do not, and either a production ratio of 50% lettuce and 50% kale or purely 100% production of lettuce.