The conducted research proved that the studied preparations affected the activity of soil microorganisms and symbiotic activity of soybeans differently. The total number of microorganisms depended on the norms of Dyesilyetand its compatible combination with Biolan and Ryzobofit.

Thus, the total number of bacteria in 10 days was within 112 % under using Biolan (20 ml/ha) and under using Ryzobofit (100 g/t) it was 114 %. Applying Dyesilyet helped to increase the total number of bacteria up to 120 %. The complex usage of Dyesilyet and Biolan increased the total number of bacteria significantly that was 130 and 136 % according to the application norms. Using Dyesilyet with Ryzobofit had the highest rates in the experiment. Here we observed the highest number of bacteria that was 138 and 144 % according to the norms of the preparations use. The number of micromycetes on the 10th day after applying of the preparations while processing by Biolan and Ryzobofit increased to 142 and 150 % respectively. Dyesilyet application ensured micromycetes growth in the number to 134-137 %. The complex use of Dyesilyet and Biolan provided micromycetes increase to 159 %, and with Ryzobofit – to 166 % compared with the control. Thus, the combined use of Biolan with Dyesilyet as well as Ryzobofit ensures the increase of bacteria and micromycetes that improves mineralization of organic residues and provides soybean plants with nutrients.

We also investigated the effects of preparations on the activity of some physiological groups of microorganisms. We found that the most sensitive to the herbicide were nitrate bacteria of I and II phase of nitrification. Application of Biolan and Ryzobofit positively impact the development of physiological groups of microorganisms. Thus, in 10 days of herbicide application they reduced in number significantly as compared to the control, especially at herbicide effect representing 91-95 % of nitrate bacteria of I phase and 92-94 % of nitrate bacteria of II phase. When using Dyesilyet with Biolan the number of nitrate bacteria of I phase increased slightly, representing 98-101 % of the control and the number of nitrate bacteria of II phase was 92-94 % of the control. The complex use of Dyesilyet with Ryzobofit boosted the number of nitrate bacteria of I phase up to 101-103 % and reduced nitrate bacteria of II phase to 86-88 %.

Ammonifiers number in the experiment depended on the norm of the herbicide and its combination with Biolan and Ryzobofit. Under applying Dyesilyet the number of ammonifiers was within 108-111 %. At combined using with Biolan the number grew to 119 and 115 % respectively. The complex application of Dyesilyet with Ryzobofit provided ammonifiers growth within 120-122 % .

Cellulose destructive bacteria were insensitive to Dyesilyet playing an important role in soil fertility. The number of cellulose destructive bacteria was slightly higher than in the control and almost did not depend on Dyesilyet norm. However, most of them are observed using Dyesilyet normally 0.6 l/ha together with Ryzobofit 100 g/t, representing 121 % of the control.

The studied preparations Dyesilet, Ryzobofit and Biolan affect positively the symbiotic activity of soybean crops and development of bacteria, micromycetes and other physiological groups of microorganisms of rhizosphere on both the 10^th and the 25^th days. Application of Dyesilyet inhibits slightly the development of individual physiological groups of microorganisms, compared with options where Ryzobofit and Biolan were used. But their number is fully restored after 25^th day.

Key words: soybean, herbicide, Dyesilyet, regulator growth, Biolan plant, Ryzobofit, soil microflora, symbiosis, tubercle bacteria.