Linking N2O flux to abiotic and biotic factors under nitrogen addition and altered precipitation
N2O flux was positively correlated with soil NO3-N (R 2 = 0.38, P < 0.05) and belowground biomass (R 2 = 0.13, P < 0.05) but was negatively correlated with soil pH (R 2 = 0.17P < 0.05) and soil temperature (R 2 = 0.16, P < 0.05) (Figure 4). Soil moisture (P = 0.77), NH4+-N (P = 0.18), and aboveground biomass (P= 0.15) were not correlated with N2O flux (Figure 4). In addition, N2O emissions were also affected by multiple biological factors (Table 3). N2O flux was negatively correlated with AOA (r = -0.435, P < 0.05) andnosZ (r = -0.484, P < 0.01) and positively correlated with AOB (r = -0.428, P < 0.05). Although N2O flux did not significantly affect nirS andnirK , it was nonetheless positively correlated with the ratio of (nirS+ nirK )/nosZ (r = 0.484, P < 0.05).