The Influence of Microbial Bioagents’ Application on the selected Soil Properties in acidic Soils

The factors limiting a successful agricultural production worldwide are certainly the availability of phosphorus (P), the soil’s organic matter, and a pH reaction in the agricultural soils. The significant amounts of phosphorus are found in the soils, but approximately 95–99% is present as the insoluble phosphates and cannot be utilized by the plants. Therefore, the increasing efforts are invested to activate the large amounts of plant-unavailable phosphorus by improving a crop’s P use efficiency through the use of phosphorus-solubilizing microorganisms (PSM). The two primary research objectives were stated, as follows: first, to assess whether the applied microbial bioagent impacts the observed soil properties (pH, organic matter, and the available P level), and second, to assess whether a microbial bioagent applied enhances the microbial biomass phosphorus (MBP). The three independent field trials were set up as a randomized blok design, with the following treatments in four replicates: a control, “C“; a control with a microbial bioagent, “CMA“; a reduced P fertilizer with a microbial bioagent, ”PMA“; and a recommended fertilization, “RF.“ The soil samples were analyzed concerning a pH reaction, plant-available phosphorus, soil organic matter, and the microbial biomass P. A visible increase from 3.45 to 5.02 mg P and from 0.53 to 3.42 mg P due to an applied mineral fertilizer was noticed at two locations. No negative impact from applied bioagents was recorded regarding the analyzed soil properties. Very strong relationships (r = 0.9213 in 2016 and r = 0.9508 in 2017) between the available P and the microbial biomass P were stated. The results indicate a fact that the P input and the application of microbial bioagent together with the content of the plant-available phosphorus in the soil influenced the MBP pool.