N 2 O contributes to increasing the greenhouse effect and is also involved in stratospheric ozone depletion. In soil and water, N 2 O reductase catalyses the reduction of N 2 O into the inert form N 2. N 2 O reductase activity is known to be affected by acidic conditions and the application of liming materials to acidic soils is now proposed as a solution for mitigating soil N 2 O emissions. During a one-year laboratory experiment, we studied the functioning of N 2 O reductase after the application of calcium carbonates to an acidic soil with a very low capacity to reduce N 2 O. The functioning of N 2 O reductase was characterised through anaerobic incubations using the acetylene inhibition technique combined with a logistic model to determine the main enzyme functioning characteristics (latency, maximal rate). Both changes in soil pH and soil capacity to reduce N 2 O were rapidly observed after the application of lime materials. The activity of N 2 O reductase was observed to be efficient throughout the experiment even when the soil had returned to initial acidic conditions, revealing a hysteretic response of N 2 O reductase to pH variations. Nevertheless, some signs of lower N 2 O reductase activity over time were observed mainly after 200 days of applying lime materials. Altogether, these results suggest that, in this soil condition, the beneficial impact of the application of liming materials on N 2 O emissions could last longer than this on soil pH.