Effect of New Strains of Phosphate-Mobilizing Microorganisms on the Bioactivity and Phosphate Regime of Common Chernozem

New strains of phosphate-mobilizing microorganisms isolated from common chernozem of the Kabardino-Balkarian Republic steppe zone were studied and a comprehensive assessment of their effect on the phosphate diet of agricultural plants was carried out in a 36-day model experiment. Pre-sowing bioactivation of the soil with 7 new strains of phosphate-mobilizing microorganisms was carried out. The commercial biopreparation Phosphatovit, created on the basis of the strain Paenibacillus mucilaginosus Pm 2906, was used as a reference, tap water was the control. As a test, barley seeds were used, which were sown on the 10th day after the introduction of microorganisms into the soil. Along with the indicators of the phosphate regime of chernozem (mobile phosphorus content and phosphatase activity), the agrobiological parameters of the soil were evaluated: basal respiration and the content of carbon extracted by hot water (S). The determinations were carried out at 3 time points: before the introduction of microorganisms, on the 10th day of incubation and 21 days after the appearance of seedlings. For a deeper understanding of the processes occurring in the soil, all analyzed samples were divided into 2 fractions: fine-earth ( 1 mm) and skeletal ( 1mm). It was found that 3 of the 7 strains (FM-18, FM-19, FM-20) showed signs of versatility, which allows them to be considered as the basis for creating commercially effective phosphorous microbiological fertilizers. Their application increased the intensity of soil respiration by 168–573%, phosphorus accumulation in barley plants by 21.4–50.0%. Under their influence, on the 10th day after application the phosphatase activity of the fine-earth part of the soil increased by 4.9–72.3% relative to the reference variant.