||The article is devoted to a two-year research of the influence of the systems of the soil treatment on the formation and functioning of microbial cenoses , the enzyme activities in the soil rhizosphere of soybean. Different systems of soil tillage were such: soil to a depth of 22-24 cm, a surface treatment to a depth of 6-8 cm, disk usage on 12-14 cm and without processing - No-tіll technology.
It is shown that the formation of microbial coenosis in the rhizosphere soil was influenced by the stage of plant growth, and soil tillage system. Revealed, that on average for two years, the number of ammonificating microorganisms in the rhizosphere of soybean was increased by 23% to the end of the growing season. The number of nitrogen-fixing microorganisms was highest in the phase of bobs breeding in the variant with surface soil tillage. The number of cellulose-destructing microorganisms has increased substantially in phase of soybean bobs breeding in the variant with No-tіll technology (211,8–792,6 x 102 CFU/g), which indicates about the active dissolution of cellulose.
It is revealed that catalase activity was increased to a phase of soybean bobs breeding (13,–7,4 ml O2/min) and was maximal in variant with plowing. Analysis of the symbiotic factors showed that maximum number of nitrogen-fixing nodules
(37,3-40,7 unit/plant) was in surface tillage and No-tіll technology. It was more on 21-15% in comparison with other variants. Nitrogenase activity was high (1,01-1,91 μmol С2Н4/plant per hour) in surface tillage and No-tіll technology and higher by 1,7-2,3 times in comparison with other variants. High biomass of nodules observed in the variants with disking and surface treatment (564-490 mg/plant).
Found, that plowing to a depth of 22–24 cm, surface cultivation to a depth of 6-8 cm and disking on 12–14 cm increased the seed yield of soybean cultivar Phaeton by 0,16; 0,31 and 0,39 t/ha (11,9; 9,7 and 5,2 %) in comparison with the technology No–tіll.