Assessment of soil carbon dioxide efflux and its controlling factors in moist temperate forest of West Himalayas

In this study, the soil CO2 efflux was measured by closed dynamic system method along with soil and meteorological parameters at 1600, 1700 and 1800 m elevations along different directional-aspects over a period of one year. The annual CO2 efflux rate (F-e) varied from 1.02 to 22.57 mu mol m(-2) sec(-1), which was highest in the rainy season. The annual average F-e was maximum (8.67 mu mol m(-2) sec(-2)) at east facing slope followed by 7.58 and 7.32 mu mol m(-2) sec(-1) at south facing slope and north facing slope respectively. Temperature (T-s), moisture (S-m) and evaporation of soil were found to be significant variables and selected to develop the regression model with R-2 value of 0.85. The effect of soil moisture on F-e above 15 degrees C T-s exhibited a better relationship with R(2 )value of 0.48 and temperature sensitivity (Q10) was found 3.25. This study reveals that the key controlling factors of CO2 efflux rate are soil moisture and soil temperature, which explains 66% variation in soil CO2 efflux.