Long‐term antagonistic effect of increased precipitation and nitrogen addition on soil respiration in a semiarid steppe |
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Authors: | Hongyan Han Yue Du Dafeng Hui Lin Jiang Mingxing Zhong Shiqiang Wan |
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Affiliation: | 1. International Joint Research Laboratory for Global Change Ecology, School of Life Sciences, Henan University, Kaifeng, Henan, China;2. College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China;3. Department of Biological Sciences, Tennessee State University, Nashville, TN, USA;4. School of Biology, Georgia Institute of Technology, Atlanta, GA, USA |
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Abstract: | Changes in water and nitrogen (N) availability due to climate change and atmospheric N deposition could have significant effects on soil respiration, a major pathway of carbon (C) loss from terrestrial ecosystems. A manipulative experiment simulating increased precipitation and atmospheric N deposition has been conducted for 9 years (2005–2013) in a semiarid grassland in Mongolian Plateau, China. Increased precipitation and N addition interactively affect soil respiration through the 9 years. The interactions demonstrated that N addition weakened the precipitation‐induced stimulation of soil respiration, whereas increased precipitation exacerbated the negative impacts of N addition. The main effects of increased precipitation and N addition treatment on soil respiration were 15.8% stimulated and 14.2% suppressed, respectively. Moreover, a declining pattern and 2‐year oscillation were observed for soil respiration response to N addition under increased precipitation. The dependence of soil respiration upon gross primary productivity and soil moisture, but not soil temperature, suggests that resources C substrate supply and water availability are more important than temperature in regulating interannual variations of soil C release in semiarid grassland ecosystems. The findings indicate that atmospheric N deposition may have the potential to mitigate soil C loss induced by increased precipitation, and highlight that long‐term and multi‐factor global change studies are critical for predicting the general patterns of terrestrial C cycling in response to global change in the future. |
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Keywords: | carbon cycling climate change grassland long‐term dynamics resource availability |
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