Seasonal and interannual variability in soil respiration in wheat field of the Loess Plateau, China

The interannual variability (IAV) in soil respiration (R[subsoil])is crucial for learning the carbon budget in the global climate change, the factors and the processes controlling the soil respiration. Variability in climate factors may directly control changes in the R[subsoil], but also may indirectly control the R[subsoil] by "function change" by changing the biological and ecological processes. We measured the soil respiration and climate factors on the winter wheat farmland in the Loess Plateau, China, for four growing seasons. The homogeneity-of-slope model (HOS model) was used to distinguish direct effect of IAV in soil respiration and the function change. Function change account for more than twice the variance in soil respiration of interannual climatic variability, it suggests that the soil respiration in the future con not be predicted from the climatic variability alone, the function change must be considered into mechanistic models.