Wyniki wyszukiwania - BazTech

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Growing Conditions and System Productivity in a Closed-Loop Aquaponic System Under Varying Stocking Density

Fabula Jeannie-Rose G., Gavino Helen F., Sace Chito F., Cinense Marvin M., Sicat Emmanuel V., Abucay Jose S.

Journal of Ecological Engineering

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2023

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Vol. 24, nr 6

25--39

EN

Aquaponics is an integrated form of a multi-commodity production system that combines a recirculating aquaculture system with the hydroponic cultivation of crops using the same water via recirculation using pumps. However, the ideal density of cultured aquatic species and the suitable fish/plants/fish feed combinations applicable under aquaponics must be established to determine its impact on the system’s performance, including the local growing conditions that could affect its productivity. Eighteen aquaponic systems following a closed-loop water recirculation method were established for the production of red tilapia, giant river prawns, lettuce, and duckweed. The study aimed to establish the ambient growing condition, water quality, and productivity of the system subjected to different stocking densities of fish (RT24 – 24 fish/m3, and RT48 – 48 fish/m3) and prawn (P0 – zero prawn, P12 – 12 prawns/m2, and P25 – 25 prawns/m2. Results show that with an ambient air temperature and humidity ranging from 30–35 °C and 52–71% during the production, the obtained water quality conditions in the system were: water temperature 27–30 °C; dissolved oxygen (DO) 2.8–3.3 mg/L; pH – 8.3; total ammonia nitrogen (TAN) close to 0, Nitrite – 0; Nitrate – 40 to 160 mg/L; total dissolved solids (TDS) – 580 mg/L; and a daily water loss of 1.47% which were within the tolerable growth conditions of the different species. The stocking density of 24 fish/m3 and 12 prawns/m2 resulted in better growth and yield performance of the cultured aquatic species. However, the stocking densities had no significant effect on the growth and yield of lettuce and duckweed.

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Effects of Fish Stocking Density on Water Quality, Growth Performance of Tilapia and Yield of Butterhead Lettuce Grown in Decoupled Recirculation Aquaponic Systems

Al Tawaha Abdel Razzaq, Wahab Puteri Edaroyati Megat, Jaafar Hawa Binti, Zuan Ali Tan Kee, Hassan Mohd Zafri

Journal of Ecological Engineering

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2021

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Vol. 22, nr 1

8--19

EN

This study was conducted over a period of 52 days to determine the effects of fish stocking density on the water quality, growth performance of tilapia and yield of butterhead lettuce cultivated in decoupled recirculation aquaponic systems (DRAPS). In this study, three respective tilapia stocking densities (treatments) of 8 kg•m-3, 10 kg•m-3, and 12 kg•m-3 were used to evaluate the butterhead lettuce in the DRAPS, which consist of two independent loops. All treatments were done in triplicates. The results showed with increased stocking density, the electrical conductivity, total dissolved substances and salinity increased and dissolved oxygen decline. The results showed that the highest stocking density produced the highest nutrients accumulation of ammonia-nitrogen (NH3-N), ammonium (NH4), nitrite-nitrogen (NO2-N) and nitrate-nitrogen (NO3-N) and potassium (K) except for phosphorus (P). Nevertheless, based on the conversion of fish feed to NO3-N and P per kilogram of feeds, the lowest stocking density provided the highest concentration of NO3-N and P. It was documented that DRAPS relied solely on the fish waste produced an insufficient concentration of N, P, K and iron. The average survival rate of tilapia in all treatments was above 94% and was not a significant difference among the treatments.

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Yield and Nutrients Leaf Content of Butterhead Lettuce (Lactuca Sativa) in Response to Fish Nutrient Solution in a Small Scale of Aquaponic Systems

Al Tawaha Abdel Razzaq, Megat Wahab Puteri Edaroyati, Binti Jaafar Hawa, Kee Zuan Ali Tan, Hassan Mohd Zafri, Al-Tawaha Abdel Rahman M.

Ecological Engineering & Environmental Technology

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2021

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Vol. 22, iss. 6

85--94

EN

This study was conducted over 52 days to evaluate the potential of using the nutrient solution produced from different fish stocking densities on the yield and nutrients leaf content of lettuce cultivated in decoupled recirculation aquaponic systems (DRAPS). In this study, three stocking densities of tilapia were used 8, 10 and 12 kg m-3, respectively. The result showed the highest total yield 448 g m-2 was obtained at a low stocking density. Also, it has been showing that with an increased fish stocking density, the leaf nutrient content of butterhead lettuce for potassium, calcium, magnesium, sodium, iron and copper was increased. While for the nitrogen, phosphorus and manganese, the higher leaf content was obtained at lower stocking density. Considering the lettuce yield, leaf nutrient contents and nitrogen dynamics, the stocking density of 8 kg m-3 could be suggested as the ideal stocking density for DRAPS.

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Analysis of economic and agricultural indicators under sustainable agriculture conditions with the use of Bayesian modelling

Grotkiewicz K.

Technical Sciences / University of Warmia and Mazury in Olsztyn

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2017

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nr 20(3)

209--225

EN

Searching for relations between the level of production intensity, land efficiency and work performance, comparative analyses were carried out on international scale taking into consideration 45 countries from around the world with the use of the Statistical Yearbook (2013) and International Statistics Yearbook (2015). The research covered basic qualification criteria of sustainable agriculture, i.e. the level of mineral fertilization and stocking density as well as productivity rates, i.e. land efficiency and work performance and factors which shape them. The main aim of the research is the use of Bayesian modelling in order to predict the development of various economical and agricultural indicators and also show relationships between events basing on the theory of probability.