Contribution of Root Respiration to Soil Respiration during Rainy Season in Dry Dipterocarp Forest, Northern Thailand

Abstract

Soil respiration (R_s) plays a key role in regulating the terrestrial carbon cycle. The nature of this role is determined by the different responses of root respiration (R_r) and microbial respiration (Rm) to environmental factors such as precipitation, soil moisture and temperature. Understanding these responses is fundamental to improving our predictions of climate change impacts on carbon cycling processes. In this study, the ratio of root respiration to soil respiration (R_r/R_s) was studied to improve our understanding of soil CO₂ emissions. The study aimed to improve our knowledge of Rr in relation to rainy season soil environmental factors in a dry dipterocarp forest in northern Thailand. With values of R_r ranging from 41.04-61.97 mgCO₂ m^-2 h^-1, with a R_r/R_s ratio from 23-48 %, the results suggest that soil moisture was a main driver for emitted CO₂ from Rr while soil temperature was only weakly related with Rr during the rainy season. However, longer-term studies are needed, including measurements of root biomass to improve accuracy and understanding of the dynamics of root respiration and their linkages with CO₂ emissions.