Abstract: As the major component of global carbon cycle, soil respiration is a key to understand belowground carbon emissions and soil organic carbon stability. However, soil respiration is composed of different components, and many key terms related to soil respiration are still onesided understood and improperly used, which hinders further research on soil carbon cycling. Thus, this paper summarized the advances in belowground carbon emissions according to the sources of carbon use, production locations and pathways for the components of soil respiration. Correspondingly, we clarified the terms related to soil respiration. Furthermore, we interpreted the contributions of different components of soil respiration to atmospheric CO₂ and their responses to global warming. Finally, combined with hot topics in current soil carbon cycle research, we emphasized the necessity and ecological significance to distinguish the components of soil respiration in terrestrial ecosystems. We prospected that exploring the mechanisms responsible for rhizosphere priming effect will be a key for the future research on ecosystem underground carbon cycling. Knowledge of rhizosphere priming effect will greatly improve our understanding dynamics of soil organic carbon and its stability.

Key words: yield, controlled release urea, N use efficiency, double-cropping rice, N leaching loss