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Practical experiences of a designing and operating a pilot aquaponic system
27-32Views:237Aquaponics is the combination of fish farming (aquaculture) and the soilless cultivation of plants (hydroponics). The aquaponics system is an artificial, recirculating ecosystem, in which bacterial processes convert the waste materials in the water used for fish rearing into plant nutrients, and therefore with the generated heat it is suitable for culturing economically valuable plants, and thus it mitigates the nutrient laden and quantity of the intensive fish producing systems’ effluent water.
The primary goal of our 12 separate unit’s aquaponics system was to gain experience. We would like to find the right plant species, which are fit for that medium, and their crop can be sold. Besides the plants, our attention focused on the fish. Two fish species were included in the experiments, the common carp and barramundi. It was difficult to create them a perfect living space, besides a constantly changing conditions temperature. Apart the above mentioned we had a problem with the number of individuals per tank, the deformity of the fish body and the too high volume of pH (we registered continuous values above 8.4). We get by carps 4.7 grams of weight gain during 15 weeks, because of the bad conditions.
The main problems at the plants are caused by aphesis and protection against sunburn. Even so we have got the multiples of field yields for each plant species. At salad has grown twice of field yields, tomatoes one and half, kohlrabi than 3.5 times more. The causes of multiple yields are the continuous balanced water and the nutrient uptake of plants. Each plant species fit for cultivating in aquaponics and their crops are delicious, chemical -free, safe and marketable. The plants should be more concentrated. After the experiment, it has been determinated that the carp is suitable for aquaponics, but greater weight gain could be achieved with optimal selection of size of rearing units.
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Microgreen leaf vegetable production by different wavelengths
79-84Views:146Microgreens are becoming more popular in gastronomy, especially as a salad ingredient. In this study, two plant species belonging to the cabbage family were grown as microgreens, namely red cabbage and broccoli. Three different light-emitting diodes (LEDs) were used in the experiment, blue, red, and combined (blue:red) lighting. The experiment was carried out by 118 µmol-2 s-1total Photosynthetic Photon Flux (PPF), LED lighting was applied for 16 hours a day. Blue light primarily stimulates leaf growth, while red light promotes flowering. In our experiment, blue and combined lighting favorably affected plant development, yield (~3000 g m-2), chlorophyll-a (~8.0 mg g-1), and carotenoid content (9.0 mg g-1). However, the red light resulted in reduced harvest yields (~2200 g m-2), chlorophyll-a (~6.0 mg g-1), and carotenoid content (~7.0 mg g-1). The development of red cabbage was favorably influenced by the blue spectrum, while the combined spectrum favorably influenced the development of broccoli.
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Folic acid content of beetroot leaf and root by different growing stages and genotypes
115-119Views:219An increasing interest has been observed of beetroot leaf as a salad component due to recent studies focusing on their nutritional value. The randomized field experiment was carried out on lowland chernozem soil with 6 varieties, 3 replications and 2 sowing dates. Sampling was performed on 23 of August 2018 at the stage of 30 and 50 days of vegetation, where leaf (30 and 50 days) and root (50 days) were collected. Total dry matter, folic acid and nitrate content were evaluated.
The results of this investigation show that higher total dry matter content was measured in the root (8.47–10.30%) compared to the leaf in both developmental stages (6.47–9.20%). Nevertheless, higher folic acid content was found in the young leaves of 30 and 50 days of development (58.77–113.86 µg 100g-1). Among the examined varieties, Bonel has presented great amount of folic acid not only in the leaves (99.35–113.61 µg 100g-1), but also in the root (89.99 µg 100g-1). Finally, lower nitrate content was found in Libero (316.16 mg kg-1) at 30 days and in Akela (340.41 mg kg-1) at 50 days of development. Thereby, fresh consumption of beetroot leaves are highly recommended.