GROWING OF LEAF LETTUCE IN AQUAPONICS SYSTEM WITH CLARIUM CATFISH

Abstract

Aquaponics is a combined system of symbiotic cultivation of aquatic organisms and plants in which aquaculture wastewater undergoes microbial transformations that are used as a source of nutrients for plant growth, while nutrient uptake by plants regenerates the water for aquaculture [1]. Using the natural life processes of freshwater animals, such as fish and shrimp, serves as a nutrient medium for growing plants. In the process of growth, plants consume the necessary products of the secretions of these organisms – chemical substances (nitrogenous, potassium, phosphorous compounds, carbon dioxide, etc.) dissolved in water, and at the same time naturally purify water and enrich it with oxygen [2]. However, we hypothesized that the feed itself can provide plant growth, and symbiosis with fish in aquaponics creates an additional beneficial effect on plant development. This relationship between fish and plants helps to increase the efficiency of the system, because the waste of the fish's life activity serves as a natural fertilizer for the plants, which ensures their growth. In this study, we grew lettuce, namely the cultivar Batavia Aficion (lactuca sativa batavia aficion) in an aquaponic system with Clarias gariepinus and added equal amounts of feed containing N and P to test the hypothesis. Lettuce plants grown aquaponically grew vigorously for up to 3 weeks and contained constant levels of nitrogen, these results suggest that catfish promote faster decomposition of feed. The yield of lettuce was 2.8 kg/m². Water monitoring in the aquaponic system showed low concentrations of nitrates, phosphorus (P), potassium (K) and magnesium (Mg), but the proportion of mineral nutrients and pH levels remained stable throughout the lettuce growing period. The electrical conductivity (EC) values recorded in this study ranged from 1.5 to 1.7 S/m due to the low rate of water exchange, which promoted greater plant growth and ion accumulation in the solution. Thanks to the continuous recirculation of water, the conditions in the aquaponic system become satisfactory for growing plants. This approach ensures constant access to nutrients and maintains the stability of the water environment, which promotes optimal plant growth.