Pedosphere 26(3): 399--407, 2016
ISSN 1002-0160/CN 32-1315/P
©2016 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Effects of temperature and moisture on soil organic matter decomposition along elevation gradients on the Changbai Mountains, Northeast China |
WANG Dan1, HE Nian-Peng1 , WANG Qing2, LÜ Yu-Liang3, WANG Qiu-Feng1, XU Zhi-Wei1 and ZHU Jian-Xing1 |
1Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China)
2Agricultural University of Anhui, Hefei 230036 (China)
3College of Geographical Science, Southwest University, Chongqing 400715 (China) |
| ABSTRACT |
| Decomposition of soil organic matter (SOM) is of importance for CO2 exchange between soil and atmosphere and soil temperature and moisture are considered as two important factors controlling SOM decomposition. In this study, soil samples were collected at 5 elevations ranging from 753 to 2 357 m on the Changbai Mountains in Northeast China, and incubated under different temperatures (5, 10, 15, 20, 25, and 30 °C) and soil moisture levels (30%, 60%, and 90% of saturated soil moisture) to investigate the effects of both on SOM decomposition and its temperature sensitivity at different elevations. The results showed that incubation temperature (F = 1 425.10, P < 0.001), soil moisture (F = 1 327.65, P < 0.001), and elevation (F = 1 937.54, P < 0.001) all had significant influences on the decomposition rate of SOM. The significant effect of the interaction of incubation temperature and soil moisture on the SOM decomposition rate was observed at all the 5 sampling elevations (P < 0.001). A two-factor model that used temperature and moisture as variables fitted the SOM decomposition rate well (P < 0.001) and could explain 80%–93% of the variation of SOM decomposition rate at the 5 elevations. Temperature sensitivity of SOM decomposition, expressed as the change of SOM decomposition rate in response to a 10 °C increase in temperature (Q10), was significantly different among the different elevations (P < 0.01), but no apparent trend with elevation was discernible. In addition, soil moisture and incubation temperature both had great impacts on the Q10 value (P < 0.01), which increased significantly with increasing soil moisture or incubation temperature. Furthermore, the SOM decomposition rate was significantly related to soil total Gram-positive bacteria (R2 = 0.33, P < 0.01) and total Gram-negative bacteria (R2 = 0.58, P < 0.001). These findings highlight the importance of soil moisture to SOM decomposition and its Q10 value, which needs to be emphasized under warming climate scenarios. |
| Key Words: Gram-negative bacteria, Gram-positive bacteria, saturated soil moisture, soil respiration, temperature sensitivity, warming climate scenarios |
| Citation: Wang, D., He, N. P., Wang, Q., LÜ Yu-Liang, Wang, Q. F., Xu, Z. W. and Zhu, J. X. 2016. Effects of temperature and moisture on soil organic matter decomposition along elevation gradients on the Changbai Mountains, Northeast China. Pedosphere. 26(3): 399-407. |
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