Effects of Warming on Soil N₂O Flux in Qingling Temperate Forest

In order to investigate the effect of global warming on soil N₂O flux from temperate forest, we conducted warming experiment using open top chambers(OTC) for 2 years in the Quercus aliena var. acutiserrata forest in Huoditang forest Station, Qinling Mountains. In this study, we explored the emission pattern of N₂O and the effect of edaphic factors after soil warming. The results showed that the annual N₂O flux increased by 13.9% with an average of (1.88±0.57) kg/(hm²·a) after soil warming, and N₂O flux was significantly increased in spring and summer. Soil warming significantly increased soil NO₃⁻−N content by 8.4% and decreased soil organic carbon and total N contents by 30.1% and 34.9%, respectively, and consequently increased C/N ration by 7.5%. The N₂O flux had a significantly positive correlation with soil temperature, water filled pore space and NO₃⁻−N content(P<0.05). There was a significantly negative correlation between soil SOC content and N₂O flux(P<0.05). The soil temperature, NO₃⁻−N content and WFPS accounted for 70% and 39.5% of the variation in N₂O flux, respectively. Therefore, soil temperature and NO₃⁻−N content were the key factors affecting N₂O emission. The projected climate warming would increase the N₂O flux in in the Q. aliena var. acutiserrata forest of Qinling Mountains.