Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8863732 | Atmospheric Environment | 2018 | 37 Pages |
Abstract
Human activities have increased atmospheric nitrogen (N) deposition, in turn changing CO2 emissions. Many studies concentrated on the relationships between the amount of N deposition and CO2 emissions. However, how N forms affect CO2 emissions is still poorly understood. A two-year field experiment was conducted to investigate the effects of N forms on CO2 emissions in the coastal wetlands of the Yellow River Delta. The N forms consisted of nitrate (NaNO3), ammonium (NH4Cl) and organic N (urea-N: glycin-Nâ¯=â¯1: 1), and the level of N addition was 8â¯gâ¯N mâ2 yrâ1. The CO2 emissions were measured in the growing season from April to October. The results showed that three types of N addition stimulated CO2 emissions (Pâ¯<â¯0.05). Compared with the control treatment, nitrate, ammonium and organic N additions increased CO2 emissions by 23.24%, 32.92% and 49.02%, respectively. Nitrate and ammonium additions produced similar and positive effects on CO2 emissions, whereas organic N addition had larger and positive effects on CO2 emissions than those of inorganic N addition (Pâ¯<â¯0.05). This may be attributed to the following reasons. First, three types of N addition tended to increase soil β-glucosidase activity and Q10 value of CO2 emissions, but only organic N addition significantly enhanced soil β-glucosidase activity and Q10 value (Pâ¯<â¯0.05). Second, inorganic N addition had neutral and negative effects on the decomposition of soil organic carbon (SOC), whereas organic N addition increased SOC decomposition compared with control treatment (Pâ¯<â¯0.05). Together, these findings highlight the significance of differentiating the influences of N forms on CO2 emissions.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Atmospheric Science
Authors
Baoxian Tao, Chenyang Liu, Baohua Zhang, Jie Dong,