DISTRIBUTION OF SOME PHYSIOLOGICAL GROUPS OF MICROORGANISMS IN SALINE SOILS ADJACENT TO KUMISI LAKE (GEORGIA)

Abstract

Aim. The study of distribution features of microbial associations of saline soils adjacent to Lake Kumisi. Methods. Quantitative determination of ammonificators was performed on meat-peptone agar (MPA), of aerobic cellulose-decomposers – on Imshenetski-Solntseva medium area, total microbial count of microorganisms (other saprophytic microflora) – inoculation on MPA after 2 days of incubation at temperature 28°С, an amylolytic bacteria and actinomycetes – on Czapek medium, nitrifying bacteria (phase I and II) – on Vinogradski mediums, fungi – on modified Czapek-Dox medium. The moisture content of soil samples was measured in a drying chamber by the gravimetric method, the pH value was determined potentiometrically using a portable pH meter (manufacturer pHep2, China), and salinity was determined by the solid residue of the aqueous extract. Quantitative estimation of microorganisms in liquid media was conducted using the Mc Credie table, and in solid areas visually by the registration of the colonies, counting colonies on Petri dishes, recalculating per 1 g of absolutely dry soil. Results. The qualitative and quantitative ratio of microorganisms within each physiological group and between them has been established. In the test samples ammonifying and amylolytic bacteria dominate. Total microbial count are found in smaller amounts, in small amount are found cellulose decomposers, fungi, actinomycetes, phase I and II nitrifies.Correlation analysis showed that there is a negative weak relationship between the number of microorganisms and the level of pH (rs = -0.03), salinity (rs = -0.14) and humidity (rs = -0.22), which indicates the absence of a reliable relationship between the studied parameters and it is possible to judge only about the presence of the corresponding trend. It was also found that the average humidity are factors affecting the total number of microorganisms. Conclusions. With increasing distance from the lake, the average value of the chemical and physical parameters of the saline soil decreases, and the total number of microorganisms increases. The analysis did not reveal a relationship between the number of microorganisms and the parameters of saline soil (pH, salinity and humidity) at certain depth points, but in comparing with the average parameters, it was found that the total number of microorganisms decreases with increasing humidity.