Abstract:

The emission of carbon from soils to the atmosphere occurs primarily in the form of CO 2 as the result of soil respiration. Increased storage of carbon in soil could help offset further anthropogenic emissions of CO 2, whereas a release from soil could significantly exacerbate the increase of atmospheric CO 2 and reinforce the greenhouse-warming effect. Because of the enormous carbon storage in soils, even a small change in soil respiration will be equal to or even exceed the annual CO 2 input into the atmosphere from land use changes or burning of mineral fuels. Thus, changes in soil respiration can have a significant positive or negative impact on atmospheric CO 2 concentrations and therefore affect climate change. Controlling soil respiration potentially can abate increases in atmospheric CO 2 concentrations. To understand the soil respiration dynamics of the broad-leaved and Korean pine forests at Changbai Mountain, and to provide a scientific basis for quantitatively assessing carbon source/sink relationships, soil respiration in broad-leaved and Korean pine forests at Changbai Mountain was measured using a static closed chamber method. The results indicated that the diurnal dynamics of soil respiration presented a single-peaked curve with the maximum occurring around 18∶00. The seasonal dynamics of soil respiration also showed a single-peaked curve with the maximum occurring in July during the growing season. The mean soil respiration rates during the growing season were 0.22 gC·m -2 ·h -1 in June, 0.32 gC·m -2 ·h -1 in July, 0.23 gC·m -2 ·h -1 in August, and 0.13 gC·m -2 ·h -1 in September. Increasing temperatures would accelerate the soil respiration rate. Compared to air temperatures, soil temperatures more precisely reflect the dynamics of soil respiration. More soil water in a certain range would improve soil respiration rates, but excessive water in soil would restrain soil respiration rates and decrease CO 2 emission rates from the broad-leaved and Korean pine forests.

Key words: Changbai Mountain Broad-leaved and Korean pine forest, Soil respiration, Global climate change