Abstract
Soil respiration (R(S)) comprises terrestrial ecosystems' second-largest carbon flux. Yet, methodological errors in R(S) partitioning and uncertainties in seasonal responses of R(S) make it difficult to predict future R(S). Here, we tested the assumption of R(S) partitioning (similar microbial respiration between planted and root-free soils), and explored two components of R(S), autotrophic and heterotrophic respiration (R(A), R(H), respectively), in a temperate grassland under monsoon continental climate. Microbial respiration in soils from planted plots was 3.88 times higher than that from root-free plots during lab incubation. In field, R(H):R(S) ratio was relatively low during non-monsoon, but increased during monsoon. The R(H) was more sensitive to temperature than R(S), indicating a greater Q(10) of R(H) than that of estimated R(A). The annual R(H):R(S) excluding the monsoon period was comparable to those reported in the global Soil Respiration Database (SRDB) and other Korean literature. This study highlights that the assumption of R(S) partitioning can be violated, that R(H) exhibits a greater sensitivity to changes in temperature and soil water content than R(A), and that annual R(H):R(S) may be similar across the globe when extreme precipitation (e.g., monsoon) is excluded.