Effects of temperature,glucose and inorganic nitrogen inputs on carbon mineralization in a Tibetan alpine meadow soil |
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| Authors: | Minghua Song Jing Jiang Guangmin Cao Xingliang Xu |
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| Institution: | 1. Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, A11 Datun Road, Chaoyang District, Beijing 100101, China;2. State Key Laboratory of Soil and Sustainable Agriculture (Institute of Soil Science, Chinese Academy of Sciences), China;3. Graduate School of Chinese Academy of Sciences, NO. 19 Yuquan Road, Beijing 100039, China;4. Northwest Institute of Plateau Biology, Chinese Academy of Sciences, 59 Xiguan Dajie, Xining 810008, China |
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| Abstract: | High levels of available nitrogen (N) and carbon (C) have the potential to increase soil N and C mineralization. We hypothesized that with an external labile C or N supply alpine meadow soil will have a significantly higher C mineralization potential, and that temperature sensitivity of C mineralization will increase. To test the hypotheses an incubation experiment was conducted with two doses of N or C supply at temperature of 5, 15 and 25 °C. Results showed external N supply had no significant effect on CO2 emission. However, external C supply increased CO2 emission. Temperature coefficient (Q10) ranged from 1.13 to 1.29. Significantly higher values were measured with C than with N addition and control treatment. Temperature dependence of C mineralization was well-represented by exponential functions. Under the control, CO2 efflux rate was 425 g CO2–C m?2 year?1, comparable to the in situ measurement of 422 g CO2–C m?2 year?1. We demonstrated if N is disregarded, microbial decomposition is primarily limited by lack of labile C. It is predicted that labile C supply would further increase CO2 efflux from the alpine meadow soil. |
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