Effects of long-term increased N deposition on tropical montane forest soil N2 and N2O emissions

Publication date: Available online 5 September 2018Source: Soil Biology and BiochemistryAuthor(s): Wenguang Tang, Dexiang Chen, Oliver L. Phillips, Xian Liu, Zhang Zhou, Yide Li, Dan Xi, Feifei Zhu, Jingyun Fang, Limei Zhang, Mingxian Lin, Jianhui Wu, Yunting FangAbstractNitrogen (N) deposition is projected to substantially increase in the tropics over the coming decades, which is expected to lead to enhanced N saturation and gaseous N emissions from tropical forests (via NO, N2O, and N2). However, it is unclear how N deposition in tropical forests influences both the magnitude of gaseous loss of nitrogen and its partitioning into the N2 and N2O loss mechanisms. Here, for the first time, we employed the acetylene inhibition technique and the 15N-nitrate labeling method to quantify N2 and N2O emission rates for long-term experimentally N-enriched treatments in primary and secondary tropical montane forest. We found that during laboratory incubation under aerobic conditions long-term increased N addition of up to 100 kg N ha−1 yr−1 at Jianfengling forest, China, did not cause a significant increase in either N2O or N2 emissions, or N2O/N2. However, under anaerobic conditions, N2O emissions decreased and N2 emissions increased with increasing N addition in the secondary forest. These changes may be attributed to substantially greater N2O reduction to N2 during denitrification, further supported by the decreased N2O/N2 ratio with increasing N addition. No such effects...
Source: Soil Biology and Biochemistry - Category: Biology Source Type: research