Short-term grazing rather than mowing stimulates N2O production potential through enhancing the bacterial pathway in semiarid grasslands

The study aimed to explore how grazing and mowing influence the archaeal, bacterial, and fungal nitrous oxide (N2O) production potential and identify the key soil factors driving N2O emissions from soil. Three treatments: fence (no grazing or mowing), grazing, and mowing were set in a field-scale experiment. Total (TNEA and TDEA), fungal (FNEA and FDEA), bacterial (BNEA and BDEA), and archaeal (ANEA and ADEA) nitrification and denitrification enzyme activities were measured to compare the effect of grazing and mowing on the potential of N2O emission. The TC varied from 16.7 to 19.0 g kg−1 and the TN content varied from 1.19 to 1.37 g kg−1 during the growing season. The TNEA, TDEA, BNEA, and BDEA were significantly higher in summer (July) (p < 0.01), and in grazing than other treatments (p = 0.01). Archaeal nitrification enzyme activity (ANEA) was significantly higher in July (p < 0.01), but showed no difference among control, grazing, and mowing. Fungal nitrification enzyme activity (FNEA) showed no difference among all treatments and seasons. Fungi made a greater contribution to TNEA and TDEA in all seasons except to TNEA in summer. Short-term grazing increased soil N2O production potential through stimulating the bacterial nitrification and denitrification in summer which was the peak growth period of grassland. Mowing did not affect the N2O production potential in all seasons, suggesting that the effect of grazing on the soil nitrogen cycle operated by microorganisms is more disturbance than mowing in this Inner Mongolia grassland.