EVALUATION OF THE EFFECTS OF MICROBIOLOGICAL AGENTS ON THE REGENERATION OF A NUTRIENT SOLUTION WHEN GROWING VIGNA RADIATA MICROGREENS IN FLOOD & DRAIN SYSTEMS

Purpose. To evaluate the effectiveness of different microbiological agents in improving the nutrient solution quality and stimulating the growth and development of the mung bean (Vigna radiata) microgreens. Methods. Statistical processing, field assessments, analytical calculations. The study was conducted in the laboratory using three main types of microbiological agents: bacteria of the genera Bacillus and Pseudomonas as well as Rhodopseudomonas palustris. The tests were conducted on samples of the mung bean (Vigna radiata) microgreens grown in Flood & Drain systems, with regular monitoring of the nutrient solution parameters (pH, concentrations of major macro- and microelements, toxic compounds). To analyze the effects of microbiological agents, I used standard methods of hydroponics and chemical analyses of the nutrient solution. The plant growth was assessed by measuring plant height, number of leaves and total biomass. Results. It was found that the microbiological agents significantly improved the nutrient solution quality. Bacillus subtilis- and Rhodopseudomonas palustris-based products reduced the concentrations of toxic compounds such as ammonium and nitrates and increased the levels of available nutrients. In the experiment, an improvement in the growth rates of the mung bean (Vigna radiata) microgreens and an increase in the number of leaves and total biomass were noted. An increase in the chlorophyll level in the leaves was observed, indicating an improvement in photosynthetic activity. Discussion. The results confirmed the positive effects of the microbiological agents on the nutrient solution quality and the growth of the mung bean (Vigna radiata) microgreens. The Rhodopseudomonas palustris- and Bacillus subtilis-containing products proved to be more effective compared to the other microbiological agents, supporting published data on their abilities to bioactivate nutrients and reduce toxic decay products. It was demonstrated that the use of the microbiological products based on Rhodopseudomonas palustris and Bacillus subtilis will allow for a reduction in costs for solution regeneration. Conclusions. The use of microbiological agents seems to be a promising approach to improve the quality and extend the period of use of nutrient solutions in Flood & Drain systems and to stimulate the growth of the mung bean (Vigna radiata) microgreens. The microbiological products based on Rhodopseudomonas palustris and Bacillus subtilis were highly efficient in maintaining optimal conditions for the growth and development of the mung bean (Vigna radiata) plants. Further research is recommended to optimize the dosage and application conditions of agents and to elucidate their interactions with other components of hydroponic systems.