Properties of Microorganisms Isolated from Soils under Conventional and Organic Farming

Abstract

Оbjective. The article presents the results of research aimed at determining the influence of different methods of tillage on the functional diversity of the soil microbiota. Soil samples containing plant residues from agricultural plots under conventional and organic farming in the Kyiv oblast were used for the study. Methods. Analysis of soil microbiota using differential diagnostic nutrient media by serial dilutions of soil suspension was performed. To quantify the phosphate-mobilizing properties of the isolated microorganisms, the concentration of phosphorus in the solution was measured (grown in NBRIP liquid medium) and detected by the Arenius spectrophotometric method on a Ulab 102UV Spectrophotometer. Results. Th e soil of the plots under organic agrotechnology of cultivation was marked by a greater number of microorganisms of all ecological and trophic groups, except oligonitrophilic and phosphate-solubilizing bacteria. The vast majority of phosphate-transforming bacteria were isolated from the soil of agricultural plots under convection farming. The largest number of cellulose-degrading isolates was isolated from the soil under organic farming plots. Five isolates have the widest range of agronomically useful properties, in particular, the ability to mobilize organic and inorganic phosphates and cellulosolytic activity: 6b, 13b, 18b, 19b, and 8m. After incubation of the isolates on an NBRIP medium at 28°C and 200 rpm for 72 hr, special analyzes for dissolved phosphorus content and pH level in the culture fluid were performed. Isolate 8m selected from chornozem (black soil) under convection agriculture and classified by us as Trichoderma sp. exhibited the highest phosphate-mobilizing activity. The vast majority of bacteria capable of phosphate transformation were isolated from the soil of agricultural areas affected by convection agriculture; and isolates capable of dissolving cellulose — from the soil of organic farming. Conclusions. The initial identification of certain isolates allowed us to classify them as Bacillus and Trichoderma. These isolates are important for further research with the prospect of creating a complex biological preparation with fungicidal properties and the ability to mobilize organic and inorganic phosphorus compounds.