[CO, release characteristics from Stipa baicalensis meadow steppe in the Hulunbeir region, Inner Mogolia, China]

Based on the measurement of soil CO2 evolution with the Li-8150 from June 2009 to June 2010, the characteristics of soil CO2 flux from the Stipa baicalensis meadow steppe in the Hulunbeir, Inner Mongolia were analyzed. The daily dynamics of soil respiration rate in this study area presented a peak curve in growing season, the daily maximum value appeared in 13:00-15:00 p. m., while the minimum value appeared in 5:00-6:00 a. m. The soil respiration had obviously seasonal dynamics, similar with the dynamics of soil temperature and soil water content. The relationships of soil respiration with soil temperature and soil water content could be better expressed with linear or exponential-power equation. Using the Van' t Hoff exponential equation to fit soil respiration and soil temperature, the results showed that they all had good exponential regression relationships in growing season and in non-growing season. Q10 was slightly different at different depths, varying from 1.68 to 2.14 in growing season and from 3.03 to 3.60 in non-growing season. The effect of soil temperature on soil respiration was more sensitive in non-growing season than in growing season. There was significant a correlation between soil respiration and soil water content at the depth of 10 cm. The annual soil CO2 fluxes were 488.47 g C x a(-1) and 507.20 g C x a(-1) in 2009 and 2010, respectively. The contribution of soil respiration in growing season to the annual soil CO2 flux was about 90%.