Influence of interactions between litter decomposition and rhizosphere activity on soil respiration and on the temperature sensitivity in a subtropical montane forest in SW China
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The aims were to identify the effects of interactions between litter decomposition and rhizosphere activity on soil respiration and on the temperature sensitivity of soil respiration in a subtropical forest in SW China.
Four treatments were established: control (CK), litter removal (NL), trenching (NR) and trenching together with litter removal (NRNL). Soil CO2 efflux, soil temperature, and soil water content were measured once a month over two years. Soil respiration was divided into four components: the decomposition of basic soil organic matter (SOM), litter respiration, root respiration, and the interaction effect between litter decomposition and rhizosphere activity. A two-factor regression equation was used to correct the value of soil CO2 efflux.
We found a significant effect of the interaction between litter decomposition and rhizosphere activity (R INT) on total soil respiration, and R INT exhibited significant seasonal variation, accounting for 26 and 31 % of total soil respiration in the dry and rainy seasons, respectively. However, we found no significant interaction effect on the temperature sensitivity of soil respiration. The temperature sensitivity was significantly increased by trenching compared with the control, but was unchanged by litter removal.
Though the interaction between litter decomposition and rhizosphere activity had no effects on temperature sensitivity, it had a significant positive effect on soil respiration. Our results not only showed strong influence of rhizosphere activity on temperature sensitivity, but provided a viable way to identify the contribution of SOM to soil respiration, which could help researchers gain insights on the carbon cycle.
KeywordsQ10 Root respiration Litter respiration Soil organic matter decomposition Soil respiration
We thank Mr. Wenzheng Yang and Mr. Xin Luo for their careful observations and measurements. This study was supported by the Natural Science Foundation of Yunnan Province, China (2011FA025), the Development Program in Basic Science of China (2010CB833501-01-07), the Strategic Priority Research Program of the Chinese Academy of Sciences, (XDA05050601-01-05; XDA05050206), and the National Science Foundation of China (31290221). We also thank two anonymous reviewers for their constructive comments in improving this paper.
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