The Influence of Consortia of Beneficial Microorganisms on the Growth and Yield of Aquaponically Grown Romaine Lettuce

Abstract

This study evaluated the effects of fish farm wastewater from the production of hybrid sturgeon (Acipenser gueldenstaedtii Brandt × Acipenser baeri Brandt) on the growth and quality parameters of romaine lettuce (Lactuca sativa var. longifolium cv. “Elizium”). The tested combinations were fish farm wastewater, fish farm wastewater enriched with one of the three microbiological consortia, and fish farm wastewater supplemented with minerals. The best growth parameters of romaine lettuce plants were obtained in the combination of wastewater from fish farming supplemented with mineral nutrients. The application of fish farm wastewater and beneficial microbiological consortia positively influenced the fresh weight of lettuce leaves and the number of leaves per plant. However, plants fed with wastewater supplemented with minerals were characterized by the strongest symptoms of leaf tip-burn and the lowest commercial value. By comparison, plants fed only with fish farm wastewater or wastewater with microorganisms were characterized by a high, similar commercial value. After the application of increased doses of minerals, there was evidence of greater activity of microorganisms involved in nutrient cycling in aquaponic lettuce cultivation. The application of the microbiological consortia and minerals significantly increased the numbers and activity of the bacteria in the culture liquids 7, 14, and 21 days after inoculation.