[The importance of using biological test objects in studying the toxicity of surface-active substances].

The Azotobacter agilis [correction of azobacter agile] culture appeared to be the most sensitive one among the studied test objects. Buckwheat as a test plant can be recommended in studying the toxicity of surface-active substances.

[Anionic surface active substances used for prevention of salt concentration in irrigated lands of hot regions].

Anionic surfactant PO-ID at the level of 10, 25 and 50 kg/ha did not depress biological activity of soil and stimulated nitrogen metabolism. Water-migration and translocation indexes of this surfactant should be studied.

[An ecologic hygiene assessment of the microbiological processes in soil contaminated with sulfonol and lead].

Alteration of the microbial coenosis and biological activity of different types of soils as well as peculiarities of survival of sanitary-significant and pathogenic microorganisms under the effect of sulphonol and a sulphonol-lead complex have been studied in the laboratory model experiment. The most sensitive tests were as follows: the number of nitrifying bacteria; nitrifying, proteolytic, dehydrogenase and cellulase activity; survival of salmonella and lactose-positive colibacilli. Under the effect of the tested sulphonol (0.

[Biological activity of the soils of the rice irrigation systems in the southern Ukraine].

The biological activity of soils was studied in the irrigation systems of the Southern Ukraina. Aerobic microorganisms were found to be widely distributed in all these soils. The cell number of Azotobacter and the activity of nitrogen fixation differed among various irrigation systems.