Improving the sanitary condition of fish pond bed by forage grass cultivation
Abstract
S.M. Nazarenko, A.P. Paliy*, A.V. Berezovskiy, A.I. Fotin, O.V. Fotin, R.V. Petrov, O.I. Kasianenko, L.N. Lazorenko, J.V. Negreba, A.P. Palii and H.I. Rebenko
The main purpose of the complex of reclamation works for the preparation of ponds for further exploitation is to create conditions for accelerating the processes of mineralization of organic substances that have accumulated during the growing season, to increase the intensity of development of the natural forage base in the next season, to reduce the risk of fish diseases. The purpose of the work was to develop an environmentally friendly method of improving the sanitary condition of the soil of the pond bed during its casting by sowing agricultural plants having bactericidal properties. The studies were performed using conventional techniques. Bacteria of the group of E. coli, Salmonella, and Enterococci were isolated from the soil of the pond bed. The sanitary and bacteriological conditions of the soil of the bed of the pond during the cultivation of different crops after 140-150 days after the water was lowered showed that by the end of the growing season (after 150 days after the casting) there is a gradual decrease in microbial contamination of the soil, reduced the amount of coli-titer and titer of Enterococci. The intensity of microbial decontamination is directly dependent on the type of fodder grown. The results of cultivation of crops 90 days after the descent of water showed that the processes of self-purification of the soil of the botanical ground are influenced by their rhizosphere - a plot of soil directly adjacent to the roots of plants and to which the root secretions and soil microorganisms act. 90 days after the descent of water, the canary grass and white turmeric were the most active in the process of remediation of contaminated soil. Compared to baseline, microbial soil contamination during this period decreased by 79.6% (p≤0.001) and 78.3% (p≤0.001, respectively). The coli-titer and Enterococci titer was 0.01. The annual activity of amaranth and rapeseed was the least active in self-purification processes. After 90 days of soil experiment, number of mesophilic aerobic and facultative-anaerobic microorganisms decreased by 61.3% (p≤0.001) and 55.7% (p≤0.001), respectively, and the coli-titer and Enterococci titer decreased to 0.01. At the end of the growing season, from the beginning of the season, a further decrease in soil microbial contamination was observed, and the intensity of decontamination was directly dependent on the type of forage grasses.