N2O production in the organic and mineral horizons of soil had different responses to increasing temperature

• Published in: Journal of soils and sediments Vol. 19; no. 10; pp. 3499 - 3511
• Main Authors: Sun, Lifei, Sang, Changpeng, Wang, Chao, Fan, Zhenzhen, Peng, Bo, Jiang, Ping, Xia, Zongwei
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.10.2019; Springer Nature B.V
• Subjects: A horizons; Ammonia; Ammonia-oxidizing bacteria; AmoA gene; Archaea; Bacteria; Denitrification; Earth and Environmental Science; Emission analysis; Emissions; Environ Risk Assess; Environment; Environmental Physics; Forest soils; genes; greenhouse gas emissions; Incubation period; NirK protein; Nitrification; nitrifying bacteria; nitrogen; Nitrogen isotopes; Nitrous oxide; nitrous oxide production; Organic carbon; organic horizons; Oxidation; sand fraction; Sec 2 • Global Change; Soil; Soil bacteria; Soil horizons; Soil investigations; Soil Science & Conservation; Soil temperature; Soils; stable isotopes; Sustainable Land Use • Research Article; Temperate forests; temperate soils; Temperature; Temperature effects; total nitrogen; Total organic carbon; Tracers; water holding capacity; O) emission; Temperature sensitivity (Q; Nitrification; Denitrification; ); Nitrous oxide (N; qPCR; N
• ISSN: 1439-0108; 1614-7480
• DOI: 10.1007/s11368-019-02316-4

Purpose The responses of N 2 O emission to increasing temperature in different soil horizons are not clearly understood yet. Here, we investigated the effects of increasing temperature on sources of soil N 2 O emissions from organic (O) and mineral (A) horizons of a temperate forest soil. Materials and methods An incubation experiment using 15 N as a tracer was conducted to investigate the sources of soil N 2 O emission and their responses to increasing temperature in the O and A horizon soils at controlled temperatures (5 °C, 15 °C, 25 °C, and 35 °C at 60% water holding capacity). The O horizon had higher total organic carbon, total nitrogen, and sand contents than the A horizon. Results and discussion The ratio of nitrification- to denitrification-derived N 2 O production decreased with increasing temperature in both soil horizons, perhaps due to the development of anaerobic volumes and the greater increase in nirS gene abundance. The nirS gene was much more abundant than the nirK gene and was more correlated to denitrification-derived N 2 O flux. No relationship was found between nitrification-derived N 2 O flux and amoA gene abundances of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) for either soil horizon. In general, nitrification dominated N 2 O production in the O horizon soil, while denitrification dominated N 2 O production in the A horizon soil. N 2 O emission was higher in the A horizon soil than in the O horizon soil, but the temperature sensitivity of N 2 O emission in the A horizon soil was lower. These differences might be explained by the higher initial anaerobic volume and higher carbon availability in the A horizon than in the O horizon. Conclusion Our results suggest that the denitrification process is more stimulated by increasing temperature compared to the nitrification process in both O and A horizons in our studied soil.