ABSTRACTLHOTSKÝ Jaroslav: Effect of Increased Nitrogen Input on Microbial Community of Forest Soils. [Bachelor Thesis] / Jaroslav Lhotský - Technical University in Zvolen. Faculty of Forestry. Department of Natural Environment. Supervisor: doc. Ing. Erika Gömöryová CSc. - Zvolen: Department of Natural Environment, 2019.Effect of increased nitrogen input on the microbial community of forest soils.In this bachelor thesis we will focus on the overview of nitrogen input into the forest ecosystems. We will evaluate the current state of nitrogen deposition in Slovakia and other European countries. The fixation and release of nitrogen in its cycle is controlled by various mechanisms caused by the activity of microorganisms. Basic mechanisms include fixation of atmospheric nitrogen, mineralization, nitrification, immobilization and denitrification. Soil microorganisms are the most active components of organic soil. We consider microbial respiration to be the simplest interpretable parameter to identify the activity of microorganisms, to measure soil quality and determine the rate of mineralization of organic matter. Excessive nitrogen inputs can affect microbial processes, cause acceleration of soil processes, acidification, and can madify the species composition of soil microbial community.