Improper management practices in agroecosystems have widely contributed to increase in the concentration of atmospheric carbon dioxide. It is thought that, at least part of the increase has been attributed to the human-induced facilitated degradation of native soil organic matter as well as the incorporated plant residue. Therefore, the soil organic C pool has been diminished while the atmospheric carbon dioxide has been enhanced. Many attentions have been focused on the carbon and nitrogen-containing greenhouse gasses as the elevated atmospheric temperature has led some unknown influences on the soil microbial phenomena. A new hypothesis has been recently raised during last years to describe the effects of elevated atmospheric temperature on selected soil biological processes. This is not well understood whether or not the hypothesis can describe the response of N mineralization, ammonification and nitrification as three vital parts on soil N cycle. Hence, the objective of the present study was to identify if the temperature-quality hypothesis can describe the response of the N mineralization processes in plant residue-amended calcareous soils. For this purpose, two calcareous soils with contrasting soil particle size distribution from Shervedan and Chamalishah, Isfahan province, were selected. Alfalfa, wheat and corn shoots were harvested, washed, dried, milled and passed through a 1-mm sieve. The plant residues were incorporated to the soils at a rate of 10 g C kg -1 soil and incubated at 8, 25 and 35 °C and 50% water holding capacity for 90 days. Control (without application of plant residues) treatments were also run for the two soils, separately. A completely randomized experiment was arranged as factorial with two factors of temperature (three levels) and plant residues (four levels including control) with three replications. Net N mineralization or immobilization, net ammonification and net nitrification rates were calculated by subtracting the initial from the final concentrations of inorganic N, ammonium and nitrate following the incubation period, respectively. The main effects of incubation temperature and plant residue application were consistently significant. Increasing incubation temperature from 8 to 35 °C was lead to increase in the net rates of N mineralization as well as nitrification in all treatments. In alfalfa treated soils, temperature caused an increase from 8 to 25 °C followed by decreasing from 25 to 35 °C. ammonification in the alfalfa-treated Shervedan soil was decreased as temperature decreased from 8 to 25 °C and then increased to 35 °C. The trend was similarly observed in Chamalishah soil for alfalfa and wheat residue-applied treatments. Activation energy (E a ) of the N cycling processes were increasing with a consistent trend (corn wheat alfalfa). The increasing trend was similarly observed for the temperature coefficient (Q 10 ) values. As a concluding remark, it should be suggested that the rates of the three processes were dissimilarly influenced by increased temperature so that the soils treated with alfalfa showed minimum Ea and Q 10 and the maximum values were observed in the corn residue-applied treatments. This response was consistently monitored either in Shervedan or Chamalishah soils. Therefore, it can be concluded that the temperature-quality hypothesis was valid for N mineralization, ammonification and nitrification. Keywords: N mineralization, ammonification, nitrification, plant residues, temperature response, temperature-quality hypothesis