The purpose of this work was identification of optimum agroecological conditions of the cespitose and podsolic soil for ammonifying and nitrifying processes. Results on studying of influence of temperature conditions (from –10 to +45 °C), humidity (0 to 30 % are given in work to the dry soil) and density (from 1,1 to 2,0 g/cm3) on ammonifying and nitrifying ability of the soil. It is established that the best conditions for nitrifying and ammonifying ability of the cespitose and podsolic soil are: soil temperature +15С; humidity of the soil 20–25 % and density of the soil is 1,1 g/cm3. At negative temperatures (–10 –5 °C) the content of nitrate nitrogen was low and didn't exceed 43,9 mg/kg, and the content of ammoniacal nitrogen didn't exceed 16,0 mg/kg. With temperature increase of the soil to +15–25 of °C nitrifying activity of the soil and the content of nitrate nitrogen increased. The maximum content of nitrate and mineral nitrogen was observed at a temperature of soil of +15 °C and made respectively 74,4 and 81,3 mg/kg. Low level of humidity of the soil 5; 10 % (15–30 % of PV) created adverse conditions for development of bacterial microflora. With increase in humidity the number of bacteria increased. Optimum conditions for ammonifying bacteria developed at humidity of the soil of 20 % (60 % of PV); for nitrifying bacteria of – 25 of % (75 % of PV). The further increase in humidity of the soil reduced quantity of bacteria that was caused by replacement of air of the soil and suppression of aerobic microbiological processes. With increase in density of the soil with 1,1 the content of nitrate nitrogen in the soil decreased to 2,0 g/cm3. The maximum content of nitrate nitrogen of 63,5 mg/kg was at the density of 1,1 g/cm3, and the smallest – 32,1 mg/kg at the density of 2,0 g/cm3. Nitrifying ability of the soil decreased similarly. Consolidation of the soil led to increase in the content of ammoniacal nitrogen and ammonifying ability.