The aim of this monograph is to present the ability of Polish soils concerning N₂O production, consumption and release (emission) to the atmosphere, soil respiration, dehydrogenase activity and CH₄ oxidation. Investigated soils comprised several taxonomic units, such as Eutric Cambisols, Haplic Luvisols, Haplic Phaeozems, Eutric Histosols, Mollic Gleysols, Haplic Podzols and Rendzic Leptosols, formed from various textural classes: sands, silts and loams. Results obtained were also related to such soil properties as soil texture, C_org, pH, Eh, ODR, reduced iron (Fe II), H₂O₂ and C₂H₂ content. The data derive from analyses of soil samples stored in the Database of Polish Arable Mineral Soils of the Institute of Agrophysics, Polish Academy of Sciences in Lublin. The samples from the upper horizons, representing tested soils, were examined in model experiments with standardized conditions (soil aeration status and temperature), which allowed to express rather the potential of soils to perform the given processes than their current conditions, but data obtained in this manner can be comparable among different soils.