Effect of the effects of different doses of mineral fertilizers on the number of ecological-trophic groups of microorganisms

Abstract

 The results of studies on the effect of mineral fertilizers on the number of ecological and trophic groups of microorganisms and the yield of winter wheat in the zone of unstable moisture in the Stavropol Territory are presented. The soil of the experimental site is ordinary chernozem, a powerful low-humus heavy-loam, the precursor is pure steam. Mineral fertilizers have been applied in various doses for 30 years, and the aftereffect of fertilizers has been studied since 2006. The total number of  microorganisms in the aftereffect of nitrogen or phosphorus fertilizers alone was low (5.53–8.0 mln columnforming units). The number of microorganisms  that transform organic forms of nitrogen in the aftereffect of nitrogen or phosphorus nutrition alone ranged from 2.62 to 4.16 mln column-forming units, and using mineral forms of nitrogen from 2.91 to 4.32 mln column-forming units. The full dose of fertilizers significantly increased the number of microorganisms that transform nitrogen compounds in the soil by an average of 15.5 mln column-forming units. The maximum total number of microorganisms was obtained in the aftereffect of high doses of nitrogen against the background of P120K120 and phosphorus together with N120K120 — 28.58 mln column-forming units and 30.21 mln column-forming units, respectively. The coefficient of mineralization in the studied soils is greater than one. With the unilateral introduction of nutrients in the soil, the intensity of microbiological processes decreases, сoefficient of microbiological transformation of organic matter — 3,94–8,64.